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Response of growth and morphology of Dracaena cambodiana seedlings, a rare and endangered plant, was studied by observing its response to five artificially controlled water supply levels. The results indicated that different levels of water supply significantly affected morphological indices and biomass. Except for specific leaf area, the ratio of leaf length to width and plant height, other indicators reached significant levels (P<0. 05). The allocation of biomass is mainly related to root traits, and there is no significant difference in chlorophyll and carotenoid content among different treatments in seedlings. According to the analysis, the seedlings could make full use of water to achieve rapid growth in the short and concentrated rainy season, and allocating more biomass to the root was good for the severe drought season after the rainy season. In summary, the seedlings of Dracaena cambodiana had strong ecological adaptability to the survival strategy of water response. [ABSTRACT FROM AUTHOR]

Using Cinnamomum saxatile as the material, a four-factor and four-level orthogonal design was adopted to explore the effects of proportional fertilization of N, P, K, Ca on the growth of one-year-old C. saxatile seedlings. The purpose of the study was to provide scientific basis for fertilization of C. saxatile. The results showed that the diameter and height of C. saxatile increased in general when the application time of N, P, K and Ca fertilizers was 30-150 d. The average value was 1. 11-1. 61 times and 1. 23-2. 17 times than the first fertilization. The effects of different fertilization treatments on the diameter and height of C. saxatile seedlings were significantly different. The best performance of growth was the combination of T8(N1P3K2Ca1 ). The effect of N fertilizer on the diameter and height of C. saxatile seedlings was significant, but the effect of P and K fertilizer was not. The effect of Ca fertilizer on height was significant, but not on diameter. The diameter growth reached the maximum at N1(100 mg / plant N) level. In conclusion, N1P3K2Ca1(100 mg / plant N+80 mg / plant P+40 mg / plant K)was the most suitable fertilizer combination to promote the growth of C. saxatile seedlings under the study conditions. [ABSTRACT FROM AUTHOR]

In order to investigate the presence of allelopathic substances that inhibit the growth of Pinus sylvestris var. mongolica seedlings, and to study the obstacles to natural renewal in P. sylvestris var. mongolica plantations, the effects of three types of extract on seed germination and the growth of 2-year-old seedlings were investigated by using pot plant experiments with mass concentrations of 1 ∶ 50, 1 ∶ 250, 1 ∶ 500 and 1 ∶ 1 000 extracts, and univariate analysis of variance, two-way ANOVA and least significant range method were used to explore the effects of three types of extracts on seed germination and growth of 2-year-old seedlings. The results showed that: 1) In the pot experiment of 2-year old P. sylvestris var. mongolica seedlings, it was found that the extract of Caragana korshinskii Kom significantly inhibited the net photosynthetic rate, chlorophyll content, malondialdehyde content and catalase activity of seedlings when the concentration was 1 ∶ 50. They were 34. 52%, 35. 58%, 30. 50% and 40. 28% lower than the control. 2) When the concentration was 1 ∶ 50, the extract of dead leaves of Carex spp. showed a trend of promoting the net photosynthetic rate, transpiration rate, chlorophyll content and malondialdehyde content of seedlings at the low concentration of 1 ∶ 1 000 and inhibiting the high concentration of 1 ∶ 50, and had a significant promoting effect at the concentration of 1 ∶ 1 000. They were 37. 71%, 49. 22%, 18. 51% and 6. 13% higher than the control. 3) The net photosynthetic rate, malondialdehyde content, catalase activity and superoxide dismutase activity were significantly inhibited when the concentration was 1 ∶ 50, which were 36. 88%, 18. 24%, 45. 10% and 20. 48% lower than the control, respectively. Among them, all the extracts of C. korshinskii Kom and Poplus spp. could promote the soluble protein of seedlings. 4) The sum of squared dispersions of 2-year-old P. sylvestris var. mongolica seedlings for net photosynthetic rate, transpiration rate, chlorophyll content, determination of malondialdehyde content, catalase activity and peroxidase activity were greater than that of the donor, and vice versa. 5) The effect of extracts on the growth stage of P. sylvestris var. mongolica seedlings was ranked as C. spp. > P. spp. > C. korshinskii Kom. Therefore, we can break up the C. spp. as fertilizer to promote the growth of P. sylvestris var. mongolica. [ABSTRACT FROM AUTHOR]

Cranberry (Oxycoccos) has strong cold resistance, and its fruit has high health value and economic value. In this study, the tissue cultured seedlings of cranberry were used as cuttings to explore the soaking and quick dipping tests of cranberry cuttings under different indole-3-acetic acid ( IAA), 1-naphthlcetic acid (NAA) and 3-indolebutyric acid ( IBA) concentrations, and the effects of different hormone types and concentrations on rooting rate, seedling height growth, biomass and root growth characteristics (including the longest root length, root surface area, average root diameter and average root number). The results showed that, when NAA soaking treatment was 100 and 200 mg / L, the root system grew well, but the longest root length was only (30. 77±0. 18) cm (NAA 100 mg / L), and the average root diameter was (0. 3±0. 02) mm. However, the longest root length of cuttings treated with IBA 1000 mg / L per hour was (30. 13±3. 22) cm, the average root diameter was (0. 39±0. 04) mm, the root surface area was (1. 27± 0. 01) cm 2, and the average number of roots was (128. 22±2. 38). From this point of view, there was little difference in root growth between the soaking treatment and the rapid soaking treatment, but in general, when the IBA concentration was 1000 mg / L, the rooting rate, was 85% at the highest. Therefore, the quick dipping method was more suitable for the rooting of cranberry tissue culture seedlings. In this study, the cutting propagation technology of tissue culture seedlings of cranberry was established for the first time, which laid the foundation for large-scale propagation of cranberry. [ABSTRACT FROM AUTHOR]

In this study, potted experiments were conducted using the early-maturing soybean variety "Heihe 43" and the late-maturing soybean variety "Dongnong 53" under low temperature treatment (LT). The shoot and root dry weights, nodule biomass, total nitrogen content, and nodule nitrogen fixation were measured in the 28-49 days after soybean emergence. The results showed that: (1) low-temperature stress encountered by soybeans in the first week after emergence would delay soybean growth and development. From the 28d to 42d after emergence, soybean biomass was significantly lower than that of the CK treatment under low-temperature stress, but no significant difference was observed in the biomass of the two soybean varieties until the 49d after emergence. (2)In comparison to CK, significant inhibition of nodule formation in "Dongnong 53" and "Heihe 43" by low temperature occurred in the 42d and 35d after emergence, and the number of nodules decreased by 58.8% and 72.0%, respectively. During the 49d after emergence, low temperature decreased the dry weight of nodules of "Dongnong 53" and "Heihe 43" by 48.9% and 48.5%, respectively. (3) Low temperature stimulated the nitrogen fixation ability of two soybean varieties. At 49d after seedling emergence, the biological nitrogen fixation, nitrogen fixation per unit nodule biomass and nitrogen fixation per individual nodule of "Dongnong 53" and "Heihe 43" at low temperature increased by 89.9%, 118.9%; 249.3%, 172.6% and 150.6%, 114.2%, respectively. The percentages of biological nitrogen fixation increased by 26.4 and 24.5 percentage points, respectively. Collectively, low temperature stress after soybean emergence can slow down growth and development, and inhibit the formation and growth of nodules. However, soybean growth will gradually recover after the release of low temperature stress. Short-term low temperature stress has a stimulating effect on the nitrogen fixation of soybean nodules and their nitrogen fixation ability, and the stimulating effect is more pronounced for the early-maturing variety "Heihe 43". Therefore, it is recommended choosing early-maturing soybean varieties to better adapt the early spring low temperature environment in the soybean production area of Northeast China. [ABSTRACT FROM AUTHOR]

As a high-quality fish with high protein and unsaturated fatty acids, Siniperca chuatsi is an important aquaculture species in Guangdong, with a stable aquaculture production that ranks first in the whole country, and the production in 2022 was 148 700 t, accounting for 37.05% of the total output of S. chuatsi in the country. With the increasing demand for high-quality aquatic products in domestic market, S. chuatsi is increasingly favored by domestic consumers. China’s S. chuatsi production has grew steadily from 2018 to 2022, with Guangdong, Hubei and Anhui ranking the top three in terms of S. chuatsi production, and the degree of industry aggregation will further increase. With the overall production of S. chuatsi in Guangdong rising on a steady trend, the domestic market share of S. chuatsi has been gradually occupied by Guangdong. Compared with China’s major freshwater aquaculture fish, the market wholesale price of S. chuatsi has a greater advantage. As a key breeding area of S. chuatsi industry in China, and the largest production area of S. chuatsi seedlings in the country, the major breeding species of S. chuatsi in Guangdong is S. chuatsi (Basilewsky), and the main production areas of the breeding are located in Foshan, Zhaoqing, Guangzhou, Qingyuan, and Jiangmen, etc. The major breeding modes are pond breeding, cage breeding, water tank breeding and factory feed breeding, with the mainly breeding way of feeding on live bait fish. There is gradual expansion of S. chuatsi aquaculture and market scale in Guangdong Province with future development trend of large-scale breeding. Taking the market price of S. chuatsi in 2022 as a reference, a cost-benefit analysis was conducted for the S. chuatsi cultured with live bait and feed. The results showed that the average total cost of feed S. chuatsi was much lower than that of live bait S. chuatsi, with a large profit margin. In regard to the deficiencies of seedling, breeding environment and feed-based mode of S. chuatsi breeding industry in Guangdong, countermeasures such as strengthening the S. chuatsi seed system, promoting the development of feed S. chuatsi stably, further building a quality and safety system for S. chuatsi, and actively pushing the transformation of S. chuatsi breeding mode were proposed to provide references for the development of S. chuatsi industry in Guangdong. [ABSTRACT FROM AUTHOR]

[Objective] The study aimed to understand the response of rhizosphere bacterial community structure and function to drought stress in cucumber seedlings. [Method] Potted water control method was used to set up drought treatment D and normal treatment N, and the rhizosphere bacteria community structure and diversity in cucumber seedlings were determined by Illumina NovaSeq sequencing. [Result] The contents of chlorophyll and soluble sugar in treatment (N) were 2.440 and 10. 380 mg/g, respectively, which were significantly higher than that of drought treatment (D), which was 1.547 and 8. 356 mg/g (P<0.05). The contents of proline and malondialdehyde in treatment D was 51.807 µg/g and 54.848 mol/g, respectively, which were significantly higher than those of treatment N (32.628 µg/g and 29.005 mol/g). The root activity of treatment N was 32.670 µg/(g·h), which was significantly higher than that of treatment D with 20.714 µg/(g·h). Superoxide dismutase (SOD) content of treatment N was 324. 826 U/g, which was significantly lower than that of treatment D with 578. 363 U/g. In the rhizosphere bacterial community of cucumber seedlings, the top five in abundance at the taxonomic level were Proteobacteria, Gemmatimonadota, Bacteroidota, Acidobacteriota and Actinobacteriota. There was no significant difference among treatments in a diversity index (Chaol, Shannon, Simpson). But PCoA analysis showed that there was significant difference in bacterial community structure between the two treatments. Comparing to treatment D, Gemmatimonadota of treatment N was obviously up-regulated, while Bacteroidota and Firmicutes were obviously down-regulated (P<0.05). LEfSe results showed that beneficial bacteria such as Muribaculaceae, Clostridia, Bacilli, etc. which mainly belonging to Bacteroidota and Firmicutes, were significantly enriched in treatment D. The functional analysis of rhizosphere bacterial community showed that the abundance of RNA processing and modification, chromatin structure and dynamics, transcription, amino acid transport and metabolism, carbohydrate transport and metabolism and other related functions of treatment D significantly increased. Furthermore the synthetic pathway related to secondary metabolites such as thiamine and the degradation metabolic pathway dominated by sugars and amino acids were up-regulated. [Conclusion] Drought stress had significant impact on the rhizosphere bacterial community structure of cucumber seedlings, which promoted the significant enrichment of beneficial microorganisms in rhizosphere soil, mainly Bacteroides and Sclerotinia, inducing and promoting the life activities of bacterial community, and significantly increased the abundance of secondary metabolites related to thiamine and degradation metabolic pathways mainly composed of sugars and amino acids. It was expected to provide new ideas for exploring the interaction mechanism of beneficial bacteria in soil that might have a positive impact on cucumber seedlings growth under drought stress. [ABSTRACT FROM AUTHOR]

The study was to investigate the effect of peanut seedling silage on the growth performance, apparent nutrient digestibility, and economic benefit of mutton sheep. Sixty mutton sheep with similar body weight and good condition were randomly divided into four groups with 15 replicates per group and one sheep per replicate. The mutton sheep in the control group were fed a whole-plant maize silage diet, 20% peanut silage was used instead of whole-plant maize silage in the experiment group 1, 40% peanut silage was used instead of whole-plant maize silage in the experiment group 2, and 80% peanut silage was used instead of whole-plant maize silage in the experiment group 3. The experiment lasted for 60 days. The results showed that the feed to gain ratio of mutton sheep in each peanut seedling silage group was significantly lower than that in the control group (P<0.05), and the average daily gain was significantly higher than that in the control group (P<0.05). The apparent digestibility of crude protein and neutral detergent fiber in the experiment group 2 and experiment group 3 was significantly higher than that in the control group (P<0.05). The serum total protein level in the experiment group 2 and experiment group 3 was significantly higher than that in the control group (P<0.05), and the urea nitrogen and triglyceride levels, and the ALT activity were significantly lower than that in the control group (P<0.05). The profit of each peanut seedling silage group was higher than that of the control group, and showed an upward trend with the increase of peanut seedling silage dosage. The study indicates that peanut seedling silage can improve the growth performance and nutrient apparent digestibility of mutton sheep, improve serum biochemical indexes, and increase breeding profits. Considering comprehensively, it is more suitable to use 40%~80% peanut seedling silage in mutton sheep breeding. [ABSTRACT FROM AUTHOR]

The decline in seedling growth of Malania oleifera as the age increases is often observed in the absence of host plants. A better knowledge of nutrient dynamics in terms of concentration and distribution patterns in different parts of the declining seedlings, the concentrations of N, P, and K were comparatively analyzed in various organs of unattached M. oleifera seedlings grown for half a year, two years, and three years. Additionally, the starch content and distribution patterns in the roots and stems of seedlings with different vigor levels were qualitatively assessed by staining cross-sections. The results were as follows:(1)As the growth vigor of M. oleifera seedlings declined, the concentrations of N, P, and K in most organs decreased, except for a significant increase in K concentration in lateral roots. The leaf N/P ratios of the declining seedlings became increasingly imbalanced, indicating different nutrient deficiency types among the seedlings with varying decline degrees. Unattached M. oleifera seedlings grown for half a year were primarily limited by insufficient N supply(with an average N/P ratio of 11.33)and subsequently by P limitation after two years(average N/P ratio 17.81). The leaf N/P ratio of unattached M. oleifera seedlings grown for three years was remarkably imbalanced(with an average value of 52.46). As the growth vigor of unattached three-year seedlings was considerably low, they are deemed unsuitable for afforestation.(2)A decrease in starch content was observed in declining seedlings, as evidenced by the reduced staining intensity of cross-sections. After three years, the starch content of unattached M. oleifera seedlings was found to have decreased to an extremely low level. Significant differences in starch content were observed at various locations, including the connecting point of the stems and roots, the basal swelling top of the root, the main root, and lateral roots, among seedlings with different degrees of decline. These findings suggested that starch content levels could serve as crucial criteria for evaluating the growth vigor of seedlings. Specifically, lateral roots were identified as optimal sampling materials for assessing seedling growth vigor through a minimally invasive method. Given the gradual decline in vitality and decreased nutrient content observed in M. oleifera seedlings grown in the absence of a host plant, it is recommended, during the propagation phase, to ensure adequate mineral nutrient supplementation, select appropriate host plants for cultivation, and facilitate early-stage transplantation. This proactive approach serves to mitigate a potential decline in survival rates during afforestation, attributed to the reduced vitality of the seedlings. The results of this study provide valuable information for evaluating seedling growth vigor and offer scientific guidance for rational fertilization in M. oleifera nurseries. [ABSTRACT FROM AUTHOR]

Acetochlor-tolerant growth-promoting bacteria were isolated and identified to develop a microbial agent and provide a feasible scheme along with a theoretical basis for this development. Highly acetochlor-tolerant bacteria were isolated from modified media with different acetochlor concentrations. The growth-promoting effect on maize was tested, and the feasibility was verified through germinationpromoting and potting experiments. Strains JL7 and JL16 showed a strong ability to induce high acetochlor tolerance and promote growth; moreover, the maximum acetochlor resistance for both strains was achieved at a concentration of 700 mg·L-1 . The phosphorus solubilization capacity of JL7 was 223.21 mg ·L-1, and the cumulative production of IAA was 82.40 mg ·L-1 . Strains JL7 and JL16 were identified as Enterbacter sp. and Acetobacter sp., respectively. The results of the germination promotion test showed that the germination rate increased by 9.42 and 3.84 percent points with the addition of strains JL7 and JL16 after 72 hours, respectively, compared with that of the CK. Furthermore, strain JL16 significantly promoted growth in terms of shoot and root lengths by 52.53% and 23.22%, respectively, compared with those of the CK. In the pot experiment, the addition of both JL7 and JL16 affected morphological indicators such as plant height, stem thickness, root diameter, and root length, all of which were promoted. Strains JL7 and JL16 were still tolerant to ethephon in the soil. Two acetochlor-tolerant strains showed a remarkable effect on promoting plant growth. The study provides a theoretical basis for microbial soil improvements by describing suitable strains and the development of innovative microbial fertilizers for future applications. [ABSTRACT FROM AUTHOR]

Horizontal planting has been used for fresh sweet potatoes in recent years. A large number of sweet potatoes can be produced, even potato block sizes. It is necessary to place potato seedlings after trenching transversely on the potato ridges when using the horizontal transplanting manually. The labor-intensive and inefficient have severely constrained the development of the sweet potato industry. However, there is no horizontal transplanting machine for sweet potatoes. In this study, a horizontal transplanting machine was designed for sweet potatoes, according to the agronomic requirements. Two rows of sweet potatoes were realized in the rotary tillage, horizontal planting, soil covering and ridge repair, and laying drip irrigation belts in one operation. High transplanting quality and transplanting efficiency were achieved in the current process of sweet potato seedling transplantation. The transplanting motion of sweet potato seedlings was theoretically studied using the EDEM-RecurDyn coupling simulation. The main influencing factors on the transplanting quality of sweet potato seedlings were determined as the forward speed of the transplanting machine, chain speed, soil depth, and seedling claw height. A coupling model was constructed to simulate the seedling operation process for the planting device-flexible sweet potato seedling-sweet potato ridge. The simulation determined that the seedling trajectory was a short cycloid, and the seedling claw height was 50 mm. An analysis was made on the movement of sweet potato seedling posture and soil particles during transplantation. The final position and ridge shape of sweet potato seedlings were confirmed, according to the agronomic requirements for horizontal planting. The Box Behnken experimental design was used with the machine forward speed, chain forward speed, and soil depth as experimental factors, while the qualified rate of planting depth, planting spacing, and transplanting efficiency as evaluation indicators. The level was also evaluated for the influence of experimental influencing factors on various experimental indicators. A quadratic regression orthogonal experiment was conducted to determine the optimization model. The validation test results showed that the optimal combination of working parameters was the moving forward speed of 0.4 m/s in the machine, the moving forward speed of 0.2 m/s in the chain, and the soil depth at 46 mm. At this time, both qualified rates of planting depth and spacing were 92% at the transplanting efficiency of 263 plants/min. The relative error between the average value of the field experiment and the optimized value was less than 5%, indicating an accurate regression model. The number of sweet potatoes planted using a horizontal transplanting machine was 3-6, and the size of the sweet potato blocks was uniform, especially suitable for the commodity properties of fresh sweet potato blocks. The transplanting machine performed better planting, fully meeting the agronomic requirements for horizontal planting of sweet potatoes. The findings can provide a strong reference for the design and optimization of sweet potato transplanting machines. [ABSTRACT FROM AUTHOR]

Grading is one of the most important steps in the tomato hole-pan seedlings. In this study, an improved YOLOv5s target model was proposed to optimize the recognition accuracy of tomato hole-pan diseased seedlings using transfer learning. The backbone part of the lightweight network (EfficientNetv2) was used as the feature extraction. The spatial pyramid pooling fusion (SPPF) module in YOLOv5s was retained to compress the number of model parameters, in order to reduce the amount of computation; The lightweight up-sampling module of CARAFE was used to introduce a small number of parameters in the Neck part of the model; And the PANet was replaced with BiFPN to optimize the accuracy of tomato hole-pan seedling identification using transfer learning. The feature weight information was introduced to enhance the fusion of features at different scales; The efficient multi-scale attention mechanism (EMA) was introduced to increase the attention for the tomato hole-pan seedlings, and reduce the background interference; The CIoU loss function was replaced by the SIoU loss function to improve the model accuracy. Direction matching between the real and predicted frame was considered to improve the convergence of the model. The mean average accuracy of the improved YOLOv5s target model reached 95.6% after training by transfer learning, which was 0.7 percentage points higher than before; The improved YOLOv5s model was 53.1% of the number of parameters in the original model, and the computation was 20.0% of the original with only 3.20G, while the weights were 53.6% of the original and the weight size was only 7.35MB, and the mean average accuracy was improved by 2.6 percentage points, compared with the original; The visualization show that the stronger feature extraction was achieved in the improved model. The feature weights were centrally distributed in the center of the burrow and the edge of the burrow holes. Meanwhile, the heat map drawn with the GradCam showed that the improved YOLOv5s model was focused mainly on the burrow seedling itself and the edge of the burrow hole, which reduced the interference of the substrate; The ablation test verified that the improved YOLOv5s model was performed the best in the detection accuracy and the frame rate, compared with the Faster-RCNN, CenterNet, and YOLO series. The findings can provide a strong reference for the grading detection and subsequent deployment of hole tray seedlings. [ABSTRACT FROM AUTHOR]

In order to investigate physiological characteristics of salt-tolerance rice HD96-1 at seedling stage, indica rice HD96-1(strong salt-tolerant)and 93-11(weak salt-tolerant)were used as experimental materials in this study. Three NaCl concentrations(0, 60, 120 mmol·L-1)was set to treat 3-leaf rice seedlings for 7 d. The growth, physiological and biochemical indexes of two rice cultivars were measured and analyzed. The results were as follows:(1)The plant height and the pseudostem width of two cultivars decreased, and the root-shoot ratio increased under salt stress; compared with 93-11, the decrease of plant height and pseudostem width of HD96-1 was lower, and the increase of root-shoot ratio was higher under salt stress; in addition, the dry weight of aboveground and root of HD96-1 increased under salt stress, while that of 93-11 decreased.(2)The malonaldehyde(MDA), superoxide anion(O2-)and hydrogen peroxide(H2O2)contents in rice seedlings increased after salt stress, of which the increase of HD96-1 was lower than that of 93-11.(3)The activities of superoxide dismutase(SOD), peroxidase(POD), catalase(CAT)and ascorbate peroxidase(APX), the contents of ascorbic acid(AsA), glutathione(GSH), proline, soluble sugar and soluble protein in rice seedlings were increased under salt stress, of which the increase of HD96-1 was higher than that of 93-11. In conclusion, the physiological mechanisms of two rice seedlings responding to salt stress are similar, but the difference is that HD96-1 with strong salt-tolerance is stronger antioxidant and osmotic regulation ability than 93-11 in response to salt stress, so that growth and development of HD96-1 are less inhibited than 93-11. [ABSTRACT FROM AUTHOR]

Pitaya(Hylocereus undatus)is a typical tropical cash crop that is not chilling-tolerant. Low temperature stress seriously affects the quality and yield of pitaya. It is an efficient and safe method to apply exogenous natural substances to improve the chilling tolerance of plants. Salicylic acid(SA)not only regulates many physiological and biochemical processes such as seed germination, growth, fruiting and senescence, but also helps plants to cope with biotic and abiotic stresses. However, the role of exogenous SA in chilling tolerance of pitaya has not been reported. To explore the effect of exogenous SA on the morphology structure and physiology of pitaya seedlings under low temperature, the leaves of ‘Zihonglong' seedlings were sprayed with SA at four concentrations(0.1, 0.3, 0.5, 0.7 mmol·L-1). after spraying for 48 h, seedlings were incubated at 4 ℃. The change in the morphology and leaf tissue structure of pitaya seedlings were observed on 0, 3, 6, 9 d. Physiological indexes such as relative electrical conductivity, contents of malondialdehyde, contents of osmotic regulators(soluble sugar, soluble protein, proline)and antioxidant enzyme(superoxide dismutase, peroxidase, catalase, glutathione S-transferase)activities in leaves were measured. The results were as follows:(1)Under low temperature stress, pitaya seedlings showed chilling injury of Grade 0, Grade Ⅰ and Grade Ⅱ. The leaf shape, color and cell structure of pitaya with different chilling injury symptoms were quite different. The percentages of Grade Ⅰ and Grade Ⅱ chilling injury of pitaya seedlings treated with SA were significantly reduced.(2)Compared with the low temperature control, SA treatment could reduce the relative conductivity and malondialdehyde contents of pitaya leaves, and increase the contents of osmotic regulators and antioxidant enzyme activities.(3)After comparing with different SA treatments, SA at 0.3 mmol·L-1 had the best effects on relieving chilling injury symptoms, reducing the relative conductivity and malondialdehyde content, increasing the soluble sugar and proline content, and increasing the activities of superoxide dismutase and glutathione S-transferase. The optimal SA concentrations for increasing soluble protein content, peroxidase activity and catalase activity were 0.7, 0.1 and 0.5 mmol·L-1, respectively. In summary, exogenous SA could alleviate chilling injury of pitaya seedlings under 4 ℃, and has a positive physiological effect on improving chilling tolerance of seedlings, and exogenous SA at 0.3 mmol·L-1 is more suitable. [ABSTRACT FROM AUTHOR]

Cerium oxide nanoparticles(CeO2NPS)have been shown to improve the salt tolerance of plant due to the potential to eliminate free radicals and the antioxidation properties. However, the effects and mechanisms of seed priming with CeO2NPS on pepper plant are unclear. To reveal impacts of CeO2NPS seed priming on the germination and seedling growth of peeper plants under salt stress, using the Maoshu 360 variety of pepper(Capsicum annuum)as material, a total of seven concentrations of treatments(0, 0.05, 0.1, 0.2, 0.3, 0.4, 0.5 mmol·L-1)and a control of un-treatment were carried out to investigate effects of CeO2NPS seed priming on seed germination rate, seedling biomass, and physiological and biochemical indexes under salt stress. The results were as follows:(1)In the seed priming with 0.5 mmol·L-1 CeO2NPS, soluble protein, content of proline, activity of catalase(CAT), content of ascorbic acid(AsA)and ratio of AsA/DHA significantly increased and levels of the superoxide anion(O2-)significantly decreased. There was no loss of viability for the seeds primed with cerium oxide nanoparticles. Indeed their germination rate and germination potential were enhanced under salt stress, and their germination index, and vigor index were improved under salt stress.(2)Under salt stress, seedlings from seeds primed with 0.4 mmol·L-1 CeO2NPS showed the highest fresh weight, dry weight, and root length; additionally, soluble protein content, AsA content and AsA/DHA ratio were also improved. In conclusion, seed priming with CeO2NPS can not only enhance seed germination under salt stress by decreasing seed water potential, accelerating storage substances metabolism and improving antioxidant capacity but also promote seedling growth through boosting protein synthesis and ascorbic acid-glutathione cycle(AsA-GSH). [ABSTRACT FROM AUTHOR]

The Guangdong-Hong Kong-Macao Greater Bay Area is located at coastal area of the opening frontier in China, with the Pan-Pearl River Delta region as the vast development hinterland, which is an important support point for the country to implement the innovation-driven development strategy and promote the construction of “The Belt and Road Initiative”. By analyzing the current situation and existing problems of aquatic product industry in nine mainland cities of the Guangdong-Hong Kong-Macao Greater Bay Area, the future development trend are judged and important development paths are put forward to promote the high-quality development of aquatic product industry in Greater Bay Area. Nine mainland cities in the Greater Bay Area are the dominant industrial agglomeration areas of aquaculture, especially the freshwater aquaculture in Guangdong Province, accounting for 49.58% and 42.28% of the province’s output value and output, respectively, and accounting for more than 50% of the province’s freshwater aquaculture area, with outstanding freshwater aquaculture capacity, which is the main area of pond aquaculture in Guangdong Province. Nine mainland cities in the Greater Bay Area have a complete chain of aquatic product industry, a high overall technical level, an advantage in aquatic seedling industry, and a relatively concentrated aquatic product processing and circulation industry. Relying on huge market consumption demand in the Guangdong-Hong Kong-Macao Greater Bay Area, the processing volume of freshwater products, the circulation of aquatic products and the total output value of service industry in nine mainland cities all exceed 50% of the whole province. From the perspective of industrial spatial layout, the aquatic product industry of nine mainland cities in the Greater Bay Area generally radiates from southwest to northeast. Jiangmen and Foshan have made outstanding contributions to the development of seawater and freshwater aquaculture in the Greater Bay Area respectively, while Guangzhou and Foshan are the polarization centers of aquatic fingerlings. At present, there are still some problems in the aquatic product industry of nine mainland cities in the Greater Bay Area, such as insufficient breeding technology, low level of production modernization, great constraints on resources and environment, less intensive processing, industrial supervision to be strengthened, and low degree of industrial integration. In order to promote the high-quality development of aquaculture in nine mainland cities in the Greater Bay Area, this study summarizes the basic path, necessary conditions and core motivation, that is, with optimizing the allocation of essential resources as a basis, improving industrial policy design and strengthening talent allocation and technological innovation to drive aquaculture modernization and green industrial development with science and technology. And concrete measures and suggestions on six aspects are put forward as follows: consolidating industrial foundation, improving supervision ability, promoting industrial integration and development, enhancing brand value, strengthening industrial digital construction and giving full play to the advantages of seedling industry. [ABSTRACT FROM AUTHOR]

Rice seedlings are highly sensitive to low temperature. Therefore it is imperative to apply new biopesticides, e.g. chitosan oligosaccharides in rice production to help rice resist low temperature stress. However, the mechanism of chitosan oligosaccharides inducing rice resistance against low temperature stress has remained unclear. In this study, Minghui 63 rice was selected to simulate the whole process of rice seedling from normal growth to low temperature stress and then to regeneration. The physiological and biochemical indexes of rice seedlings in the corresponding periods were determined, and the metabolic pathways of differential proteins of rice seedlings were identified and analyzed by label-free quantitative proteomics technology, so as to explore the induction mechanism of chitosan oligosaccharides on rice seedlings resistance to low temperature stress. The photosynthetic pathway and starch sucrose metabolism were also discussed in detail. The results showed that chitosan oligosaccharides could regulate the abundance of common proteins in rice and resist the influence of low temperature stress on photosynthesis. Chitosan oligosaccharides also had a certain impact on the abundance of expressed proteins. It could also promote sucrose decomposition and starch accumulation to convert into glucose donors for rice growth and metabolism. This study provides important practical guidance for the breeding of cold-resistant rice, and scientific basis for the research and utilization of cold-resistant rice and new biological pesticides. [ABSTRACT FROM AUTHOR]

[Objective] The study aimed to analyze the effect of fertilizer with different ammonia-nitrate ratio on rice seedling quality aud soil nutrient insufficient fertilizer supply in the late period of traditional seedling fertilizer. [Method] In the study, a 2-year rice seedling experiment was conducted to investigate the effects of different ammonia-nitrate ratio on rice seedling quality and soil nutrient chauge, through replacing ammonium sulfate of rice seedling fertilizer by nitrate sulfur fertilizer. Four treatments were carried out in the study, including CK ( 100% conventional rice seedling fertilizer), NSl ( 70% rice seedling fertilizer + 30% nitrate sulfur fertilizer), NS2 ( 50% rice seedling fertilizer + 50% nitrate sulfur fertilizer) aud NS3 ( 100% nitrate sulfur fertilizer). [Result] Compared with CK treatment, there was no significant difference for rice seedling growth ratio from treatments of nitrate sulfur fertilizer replaced ammonium sulfate, which illustrated that it was a suitable fertilizer for rice seedling. Compared with CK, NSl and NS2 treatments significantly improved seedling quality ( leaf age, stem base width, plaut height, leaf length aud biomass) through chauge of ammonia-nitrate ratio from rice seedling fertilizer. Compared with CK treatment, NS3 treatment had no significant difference in rice seedling quality( leaf age, stem base width, plant height, leaf length and biomass) . At the late stage of rice seedling ( 28 - 35 days), NS3 treatment significantly reduced the chlorophyll ( SP AD) content of rice seedlings. Compared with CK treatments, the nitrate sulfur fertilizer replaced ammonium sulfate ( NSl, NS2 and NS3) could significantly decrease the content of NH4+ -N and increase the content of NO3- -N. With the increase of nitrate sulfur fertilizer replaced ammonium sulfate ratio, soil total nitrogen content also decreased gradually. [ Conclusion] Nitrate sulfur fertilizer partly replaced anuuonium sulfate can promote seedling growth by optimizing ratio of anuuonia and nitrate, but total replacement of nitrate sulfur fertilizer will increase the risk of nitrogen loss. [ABSTRACT FROM AUTHOR]

【Objective】An efficient factory breeding technology system for tissue cultured seedlings of Mussaenda hybird was established to provide technical support for the large-scale production of the variety.【Method】The stem tips and stem segments of the mother plant of M. hybird were used as explants to study the effects of different disinfection types and treatments, basic medium types and hormone ratios and light quality on the reproductive efficiency of their seedlings. And the effects of different seasons on the survival rate and growth of transplanted seedlings were explored.【Result】 Explants of M. hybird were easy to die when exposed to alcohol, and sterile water washing could reduce the toxicity of alcohol to explants; 10% H2 O2 treatment for 10 min and 0.1% HgCl2 treatment for 8 min could obtain a large number of sterilematerials. Explants had high bud induction rate and strong buds when cultured on 3/2MS + 6-BA 3.0 mg/L + NAA 0.2 mg/L. According to the results of the effects of proliferation methods under different formulations on factory production efficiency of tissue cultured seedlings, propagation of M. hybird was more efficient on 3/2MS + 6-BA 0.5 mg/L + NAA 0.1 mg/L + peptone 0.1 g/L by stems; the rooting rate of tissue cultured seedlings was 100% on 3/2 MS + NAA 0.04-0.05 mg/L + IBA 0.01 mg/L, the roots were strong, and the plants grew well. There were significant differences in the effects of different seasons on the domestication and transplanting of tissue cultured seedlings of M. hybird. It was found that significant differences in the growth and development and chlorophyll content of tissue culture seedlings with different light qualities. Fluorescent lamp treatment was suitable for proliferation and propagation, and LED with 80% red light +20% blue light was suitable for strong seedlings cultivation at rooting stage.【Conclusion】Effective disinfection method of explants, and suitable medium formula and light quality conditions for the induction and proliferation of buds were obtained, which provided a theoretical basis for the factory breeding of Mussaenda hybird. [ABSTRACT FROM AUTHOR]

【Objective】The effects of exogenous gibberellin on seed germination and seedling growth of passion fruit under salt stress were studied. 【Method】Different concentrations (50, 100, 150 mg/L) of NaCl solution were used to simulate salt stress, and different concentrations of gibberellin were used for seed soaking treatment (50, 100 mmol/L) and foliar spraying treatment (25, 50 mmol/L) of passion fruit. The physiological regulation effects of exogenous gibberellin on passion fruit under salt stress was analyzed by measuring the germination and physiological indexes of the seeds, as well as the growth and physiological indexes of the seedlings. 【Result】Under 150 mg/L NaCl stress, 50 mmol/L gibberellin soaking treatment could increase the germination rate and germination index of passion fruit seeds by 20.4% and 16.3%, respectively. It promoted the increase of embryo length and radicle length of passion fruit by 7.9% and 20.5%, respectively. At the same time, the MDA content decreased by 10.8%, the soluble protein content, SOD activity and POD activity increased by 5.5%, 21.3% and 28.5%, respectively. After spraying 25 mmol/L gibberellin on the leaves under 150 mg/L NaCl stress, the number of leaves, plant height, root length and stem diameter of passion fruit seedlings increased by 16.3%, 20.3%, 20.9% and 19.4%, respectively; furthermore, the chlorophyll content of leaves, soluble protein content, SOD activity and POD activity of the seedlings increased by 13.0%, 26.2%, 12.0% and 9.3%, respectively.【Conclusion】The seed soaking treatment with gibberellin solution could significantly promote the germination of passion fruit seeds under salt stress, and had a significant alleviating effect on the inhibition of embryo and radicle growth. Foliar spraying gibberellin could significantly alleviate the effects of 100 and 150 mg/L salt stress on the growth of passion fruit seedlings, especially for 150 mg/L salt stress seedlings. [ABSTRACT FROM AUTHOR]

【Objective】The study was carried out to explore the effects of cutting seedlings on the growth and yield of maize under substrate covered no-tillage sowing, which would provided reference for improving maize yield under this sowing mode. 【Method】The ‘Huiyutian 3’ was used as the experimental material, and the split plot design was adopted for studying the effects of cutting seedlings on growth, development traits and yield of maize under substrate covered no-tillage sowing. The main plot was four different planting densities (6.0×104 , 7.0×104, 8.0×104, 9.0×104 plants/hm², respectively marked as A1-A4), the subplot was four different cutting treatments (3-4 leaf age, 5-6 leaf age, 7-8 leaf age, respectively marked as T1-T3), and the control without cutting seedlings was CK. 【Result】Cutting seedlings had no significant effect on growth cycle and the SPAD value of leaves in the filling stage of maize under substrate covered no-tillage sowing. With the increase of planting density, stem traits and ear traits showed a downward trend. Under the planting density of A1-A3, with the increase of planting density, the yield of maize increased, and the yield of maize decreased relatively under the planting density of A4. The plant height and ear height were significantly reduced, and the stem thick were significantly increased by cutting seedling under A1-A4 planting density, the effect was T2 > T1 > T3. Similarly, the spike length, spike diameter, kernel rows, row grains, panicle weight and yield were improved by cutting seedling under A1-A4 planting density, and the effect of T2 was the best. Compared with CK, the average yield of A1-A4 planting density under T2 treatment increased by 3.80%, 11.71%, 15.49% and 13.24%, respectively. Under A3 planting density, the effect of cutting seedling treatment on promoting yield was significantly better than that of other planting densities, and the yield of T1-T3 treatment increased by 13.53%, 15.49% and 8.98%, respectively.【Conclusion】Cutting seedlings could reduce the center of gravity and improve stem diameter of maize under substrate covered no-tillage sowing. Furthermore, it promoted the positive growth and development of ear traits such as ear length, ear diameter, row number per ear, grain number per row and grain mass per ear, and effectively improved the yield under substrate covered no-tillage sowing. Under the planting density of 8.0×104 plants/hm2 , the effect of cutting seedlings at 5-6 leaf ages was the best. [ABSTRACT FROM AUTHOR]

In-field hybrid rice nursing seedling, because of the low sowing rates, the existence of insufficient seed strip forming and seed uniformity in trays cause the problem of poor seedling quality and low planting uniformity. To solve the problem, this study presents a furrow opener with press roller for precision drill nursing seedling of hybrid rice. Based on the principle of rolling trenching and analysis of the interaction law between the rollers and subsoil of the seedling tray, ideal seed trenches suitable for hybrid rice precision seedling seeding was constructed. Coupled transplanting experiment was conducted to test the ditching effect. The specific structure and working principle of the furrow opener with press roller are described. The kinetics analysis among the press roller, load adjusting mechanism, seedling tray and subsoil, as well as the soil subsidence calibration test were conducted. The structure and parameters of the key components of furrow opener with press roller are designed and optimized. Discrete element simulation test and the Box-Behnken test method are conducted, the key parameters of the press roller was optimized using multi-objective optimization. Then, verification test is conducted to obtain the key parameters of the press roller with100mm of the diameter of the press roller, 45° of the V-shaped tooth angle, and 9mm of the ditch depth. Meanwhile, the verification tests show that the uniform qualified rate was 85.68% and strip forming qualified rate was 87.18%, which is consistent with the optimization results. The field experiments showed that compared with no-ditching drill sowing， the uniform qualified rate and the strip forming qualified rate of the ditching drill sowing increased by 5.78% and 17.17 %， respectively. The highest uniform qualified rate and strip forming qualified rate achieved 86.80% and 87.60%, respectively. According to the coefficient of variation of seedling quality, the consistency of seedlings was significantly improved. In-field rice mechanized transplanting, the missing plant rate of the ditching drill sowing decreased by 1.95%, the rate of 1-3 plants per pot increased by an average of 7.14%, and the root damage rate decreased by an average of 2.27%, compared with the noditching drill sowing. When the seeding density is 50, 60, and 70 g/tray, the theoretical yields of the ditching drill sowing were 234.90, 245.55 and 57.15kg/hm2 higher than that of no-ditching drill sowing, which increased by 3.12%, 3.53% and 0.80%, respectively. When the seeding density is 50, 60, and 70 g/tray, the actual yields of the ditching drill sowing were 381.60, 365.85 and 180.15kg/hm2 higher than that of the same sowing density with no-ditching drill sowing, with increased by 5.00%, 5.33% and 2.52%, respectively. The results of the study show that the furrow opener with press roller performs well and can effectively improve the technical level of precision strip seeding and precision coupling transplanting. The results of the study can provide a reference for the research and development of hybrid rice precision strip seeding equipment. [ABSTRACT FROM AUTHOR]

To explore the effects of different concentrations of naphthalene acetic acid (NAA) on root morphology and endogenous hormone content of Phoebe sheareri seedlings and the regulatory effects of NAA on the root development of Phoebe sheareri seedlings, the germination seedlings of mature seeds collected from the same branch of the mother tree were selected as the research objects. Concentrations of 0, 25, 50, and 75 mg L-1NAA were used to analyze the regulatory effects of NAA on root morphology and endogenous hormone content of Phoebe sheareri seedlings. The results showed that NAA treatment, inhibited taproot elongation, increased taproot diameter and total root surface area, and increased total root biomass significantly (P<0.05). The total root surface area and total root length reached their maximum when the concentration of NAA was 75 mg L-1. The number and total length of primary lateral roots increased and reached the maximum, respectively. Exogenous hormone NAA could significantly increase the content of trans-zeatin (TZ) in root system of the seedlings (P<0.05). The root topological index significantly increased with the increase of NAA concentration (P<0.05), and the root system evolved towards the fishtail branching type. Treatment with 75 mg.L-1NAA significantly increased the root biomass and TZ content (P<0.05) but significantly reduced the root endogenous hormone abscisic acid content (P<0.05). These results indicate that NAA treatment could promote the synthetic accumulation of root TZ and promote the development of root system. [ABSTRACT FROM AUTHOR]

[Objective]In order to understand the seed characteristics and the sowing seedlings technology of Zelkova sinica. [Method] The seed morphological characteristics, setting characteristics, treatment methods, sowing period and seedling growth rhythm were studied. [Re)sult]The results showed that Zelkova sinica fruiting has obvious phenomenon of big and small year, between those years, there were significant differences in thousand grain weight and kernel percentage of unhydrated seeds. In the big year, unhydrated seeds’ thousand grain weight and kernel percentage could reach 54. 20 g and 38. 66%, while in the poor year, the data of these two indicators were only 15. 96 g and 5. 20%. In large-scale production, winter sowing has obvious advantages, and the seedling emergence rate and seedling formation rate were higher, which could reach 59. 72% and 36. 53%. In contrast, the seedling formation rate of autumn sowing was very low, and the spring sowing needs about 45 d of low temperature stratified sand storage treatment. The annual growth rythm of the seedlings was “ slow-fast-slow”. The active growth period was from May to September. [Conclusion]According to seed setting characteristics and the growth characteristics, it would have great significance to improve the seedling quality and production efficiency by adopting appropriate sowing method and periodical seedling measures. [ABSTRACT FROM AUTHOR]

[Objective]To study the physiological response of different bitter gourd materials at seedling stages to high temperature stress, preliminarily evaluate the heat resistance of this materials, and provide theoretical basis for the subsequent breeding of heat-resistant varieties of bitter gourd.[Method]This study used 10 high-generation inbred lines (KG1-KG10) and 6 hybrid varieties (KG11-KG16) of bitter gourd as test materials. Different bitter gourd materials were subjected to high temperature cycling at 40 ℃ /12h during the day and 25 ℃ /12h at night for 3 days. The relative electrical conductivity (REC), malondialdehyde (MDA) content, proline (Pro) content, and antioxidant enzyme activity of seedling bitter gourd leaves were measured. And the heat resistance of these 16 bitter gourd materials was preliminarily evaluated using the membership function method.[Result]The relative electrical conductivity (REC) of the leaves of 16 bitter gourd materials increased during the seedling stage under high temperature compared with normal temperature conditions. Among them, the bitter gourd materials with significant differences in increase were KG1, KG2, KG9, KG10, KG11, KG13, KG14, KG15, and KG16. Except for KG1 and KG2, the content of malondialdehyde (MDA) in the other 14 bitter gourd materials decreased. Among them, the bitter gourd materials with significant differences in decrease amplitude were KG3, KG4, KG5, KG6, KG8, KG10, KG11, KG12, KG13, KG14, KG15, and KG16. The content of proline (Pro) also increased and decreased, with 6 bitter gourd materials showing an increase in Pro content in their leaves. The bitter gourd materials with significant differences in increase were KG1, KG2, KG3, KG4, and KG10; However, 10 bitter gourd materials showed a decrease in Pro content in their leaves, KG6, KG7, KG8, KG9, KG11, KG14, KG15, and KG16 showed significant decrease . Among the antioxidant enzyme activities, the peroxidase (POD) activity of leaves of 16 bitter gourd materials increased significantly, while the activities of superoxide dismutase (SOD) and catalase (CAT) increased and decreased. The SOD activity of bitter gourd materials KG5 and KG14 decreased, while the SOD activity of the other 14 bitter gourd materials increased to varying degrees. The bitter gourd materials with significant differences in increase were KG1, KG2, KG3, KG4, KG6, KG7, KG8, KG9, KG10, KG11, KG12, KG15, and KG16; The CAT activity of bitter gourd materials KG8, KG10, KG12, and KG16 significantly increased, while the CAT activity of the other 12 bitter gourd materials decreased to varying degrees. The bitter gourd materials with significant differences in decline were KG1, KG2, KG3, KG4, KG5, KG7, KG9, KG11, KG13, and KG14. Through comprehensive evaluation using the membership function method, it was preliminarily determined that the heat resistance of these 16 bitter gourd materials is in the following order: KG1>KG2>KG16>KG11>KG10>KG3>KG9>KG12>KG15>KG4>KG13>KG8>KG6>KG5>KG7>KG14.[Conclusion]Different bitter gourd materials have undergone different changes in six physiological indicators under high temperature stress, further indicating that these six physiological indexes have varying degrees of correlation with the heat resistance of bitter gourd. Preliminary evaluation showed that the KG1, KG2, KG16, KG11, and KG10 bitter gourd materials with better heat resistance have potential application value and can be utilized in subsequent bitter gourd heat resistance breeding. [ABSTRACT FROM AUTHOR]

Inferior bowl seedlings have posed a great threat to the survival rate of later seedling transplantation in greenhouse hole tray seedling cultivation. It is urgent to remove the matrix blocks of these holes before leaving the factory. However, the existing mechanical removal often causes the particle scattering and omission. Air suction removal can be expected to effectively compensate for this defect. In this study, a series of experiments were conducted to optimize and then verify the structural parameters in the matrix air suction removal scheme. A systematic analysis was implemented to determine the relationship between pipeline design and adsorption efficiency under negative pressure. A single factor experiment was also carried out to preliminarily select the optimal values of pipe diameter (10, 18, 26, and 32 mm), pipe spacing (0, 4, 8, and 12 mm), and pipe length (1 000, 2 000, 3 000, and 4000 mm). A optimal combination was obtained with the pipe diameter 26 mm, pipe spacing 6 mm, and pipe length 2 000 mm. Further expansion was carried out with 200-hole potted seedlings as the research object (The seedling emergence rate of the entire tray was 92%, and the health rate was 86%). Four factors were performed on the substrate removal rate, including pipe type (round tube, flat tube, and square tube), pipe diameter (inner diameter of 23, 26, and 29 mm), pipe spacing (2, 6, and 10 mm), and pipe length (1 000, 2 000, and 3 000 mm). Response surface analysis was conducted as well. The experimental results show that all four factors posed an impact on the matrix removel rate. Firstly, the pipe spacing and the pip type shared the greatest impact on the matrix removel rate, and then the pipe diameter. Nevertheless, there was the little effect of pipe length on the cleaning. Reasonable scaling was carried out in the later experimental design. Secondly, the larger the pipe diameter was, the better performance was. It was also necessary to consider the limitation of hole space and the damage to adjacent hole healthy seedlings. The smaller the pipe spacing was, the greater the negative pressure capacity was, and the better the matrix removel rate was, but the suction cup phenomenon was more serious. There was the little impact of the pipe length on the overall suction, but it cannot be ignored. Finally, the optimal combination of various factors was achieved: a square tube, an inner diameter of 26 mm at the end of the straw, a distance of 3 mm from the end of the straw to the port on the hole, and a length of approximately 1000 mm. Consequently, 95% matrix removal was achieved at the maximum negative pressure of 22 kPa,which is an average increase of 2.94% compared to before optimization. More efficient substrate removal was achieved under the same negative pressure. The better performance was gained than the mechanical removal equipment of low-quality bowl seedling substrate. This finding and also provide the data reference for the design and development of removal equipment with substrate negative pressure. [ABSTRACT FROM AUTHOR]

【Objective】 This study aims to explore the effects of Bacillus siamensis EM-1 and Pseudomonas rhodesiae MTD4-1 on the growth and development of tobacco seedlings at the seedling stage and root extending stage. 【Method】 Two microbial agents were added to the seedling substrate respectively to study their effects on the microbial diversity of rhizosphere seedling substrate and tobacco seedings root, as well as the morphological and physiological indexes of tobacco seedlings. 【Result】 Compared with control, the addition of EM-1 bacterial agent could significantly promote the microbial diversity of rhizosphere seedling substrate and tobacco root system at seedling stage, with the increase rates of 9.40% and 34.70%. During this stage, EM-1 bacterial agent can also significantly improve the phenotype and physiological indexes of tobacco seedlings. Compared with the control, its root dry weight, total root length, total root surface area, average root diameter, total root volume, shoot dry weight, seedling height, stem diameter, maximum leaf length, maximum leaf width, root activity, chlorophyll a and total chlorophyll content at the seedling stage increased by 68.81%, 42.55%, 58.08%, 10.10%, 75.83%, 36.27%, 46.63%, 33.56%, 31.10%, 37.97%, 27.04%, 40.00% and 32.14%, respectively. Similarly, the addition of MTD4-1 bacterial agent could also significantly promote the microbial diversity of tobacco root system at seedling stage, with the increase rates of 9.59%. MTD4-1 bacterial agent can also significantly improve the phenotype and physiological indicators of tobacco seedlings at root spreading stage. Compared with the control, the root dry weight, total root length, total root surface area, shoot dry weight, seedling height, stem diameter, maximum leaf length, and maximum leaf width at root extending stage increased by 45.35%, 118.94%, 65.89%, 27.12%, 34.56%, 23.90%, 26.58% and 32.94%, respectively. Correlation analysis showed that a significant correlation between the root microbial diversity of tobacco seedlings and the microbial diversity of rhizosphere seedling substrate, total root length, average root diameter, chlorophyll a and total chlorophyll content of tobacco seedlings (P < 0.05). There was a highly significant correlation between root microbial diversity and total root surface area and total root volume (P < 0.01). The total root length of tobacco seedlings was significantly positively correlated with the total root surface area and chlorophyll content (P < 0.01).【Conclusion】EM-1 bacterial agent mainly promotes tobacco seedling growth by increasing the diversity of tobacco rhizosphere microorganisms at the seedling stage, while MTD4-1 bacterial agent mainly promotes tobacco seedling growth by increasing the diversity of tobacco rhizosphere microorganisms at the root extending stage. The quality of tobacco seedlings during the seedling cultivation period and after transplantation will be improved by adding EM-1 and MTD4-1 into substrate respectively. [ABSTRACT FROM AUTHOR]

In order to clarify the growth-promoting activity of volatile organic compounds(VOCs) from Trichoderma viride T5, and to explore the broad-spectrum and stability of its growth-promoting effect, in this study, the seeds and seedlings of 8 crops were selected as experimental materials, the crops were millet, quinoa, wheat, cabbage, tomato, pepper, cocozelle, and pumpkin. The effects of VOCs from T. viride T5 on seed germination and seedling growth of these 8 crops were studied by plant- microbial volatile sealed co-culture. The results showed that VOCs from T. viride T5 could promote the seed germination and the seedling growth of 8 crops. The rates of seed germination of millet, quinoa, cabbage, tomato, pepper, and cocozelle were significantly increased by treatment of VOCs, and the rate of germination of cocozelle seed was increased most obviously with the growth-promoting rate of 17.9%. VOCs showed the root growth-promoting rate of 71.6% on cabbage seed and showed the bud growth-promoting rate of 53.7% on pepper seed. After 12 d of treatment by VOCs, the growth-promoting rate of the above-ground part of quinoa seedlings was 54.2%. The growth-promoting effect on the underground part of pumpkin seedlings was the best and reached 120.2 mm, with the growth-promoting rate was 69.4%. The growth-promoting rate of fresh weight of cabbage seedlings reached 42.2%, and the growth-promoting rate of dry weight of cocozelle reached 81.8%. In conclusion, T. viride T5 had a strong growth-promoting effect on seed germination and seedling growth of cereal and vegetable crops, it was an active potential strain with broad-spectrum growth-promoting effect, and it could be used as a microbial resources for biocontrol strain screening and active metabolite research. [ABSTRACT FROM AUTHOR]

To determine the effect of nutrient addition time and amount on the quality of the rhizome and its promotion on the quality and morphological plasticity of young bamboo, a breeding seedling experiment with two nutrient addition times (15 and 30 days before breeding seedlings) and four nutrient addition amounts (high amount (45 gpot, HA), medium amount (30 g pot, MA), low amount (15 g pot, LA), and control (0 g pot', CK)) for first-year rhizomes of Indocalamus decorus was conducted. The growth, leaf morphological plasticity, biomass accumulation, and allocation of young bamboo were determined. As the nutrient addition time increased, the height, mass, and germination rates of young bamboo treated with low and medium nutrient addition amounts decreased overall. In contrast, the young bamboo under the high nutrient addition amount increased. The leaf and root biomass proportions of young bamboo and leaf morphological plasticity decreased gradually while the culm biomass proportion increased. Furthermore, the culm, leaf, root, total biomass, and leaf chlorophyll a and a+b contents of young bamboo receiving the medium amount of nutrients 15 d before breeding seedlings were significantly higher than those when nutrients were applied 30 d before breeding. As the nutrient addition amount increased, the seedling quality and leaf morphological plasticity of young bamboo first increased and then decreased. Moreover, biomass accumulation in young bamboo treated with a medium amount of nutrients was much higher than that in young bamboo under the other treatments, and the leaf biomass proportion increased significantly. These results indicate that nutrient addition before seedling breeding greatly influenced germination, growth, leaf functional plasticity, and biomass. In addition, the medium amount of nutrient addition (30 g pot) 15 d before seedling breeding promoted the quality of rhizome segments and increased the germination, growth, leaf morphological plasticity, and biomass accumulation of young bamboo; thus, it was the most suitable form of nutrient addition for breeding seedlings of I. decorus from rhizome segments. [ABSTRACT FROM AUTHOR]

【Objective】 Barthea barthei (Hance ex Benth.) Krass. is a unique shrub of the genus Barthea in Melastomataceae in China, which has important ornamental value. However, it is mainly distributed in the wild, and its artificial cultivation technology system has not been fully established, which greatly limits its application potential as a landscape plant. In this study, by comparing the effects of different types in nutrients and different application concentrations on the growth and root indexes of the seedlings, the main nutrient dosage affecting the growth of the seedlings was determined, providing a scientific basis for the cultivation of the seedlings.【Method】 The tissue culture seedlings of B. barthei were used as materials, and they were transplanted into the seedling cups with yellow soil as the cultivation substrate. After 3 months’ culture, 6 kinds of N nutrients (Glutamic acid, Alanine, Aspartic acid, Compound fertilizer, Urea, Controlledreleased fertilizer) and 3 kinds of application amount (0.7, 1.4 and 2.8 mg/plant) were applied respectively. The seedling height and chlorophyll content of B. barthei were measured monthly, and the root indexes of B. barthei was measured after the experiment. 【Result】Nutrient type and application amount had significant effects on the early growth and development of B. barthei seedlings. The highest increment of seedling height was 5.18±0.13 cm after 1 month of treatment with T9 (Aspartic acid, 2.8 mg/plant ). The increment became smaller after 4~5 months. The seedling height increment of seedlings treated with T5 (Alanine, 1.4 mg/plant) was not significantly different from that of the control in the first 2 months, but it was much higher than that of the control after the 4th and 5th months. The increment of seedling height of T18 (Controlled-released fertilizer, 2.8 mg/plant) was the largest after 4 and 5 months. The root biomass of T14 (Urea, 1.4 mg/plant ), T9 (Aspartic acid, 2.8 mg/plant ) and T15 (Urea, 2.8 mg/plant ) were the largest, which were 0.71 (±0.40) g, 0.65 (±0.21) g and 0.64 (±0.24) g, respectively. The root surface area with diameter less than or equal to 2 mm under T9 treatment was 273.63 cm2, which was significantly higher than that under other treatments.【Conclusion】Considering the seedling height and root index of root surface area with diameter ≤ 2 mm, the best nutrient for the early stage of B. barthei growth was Aspartic acid with the amount of 2.8 mg/plant. [ABSTRACT FROM AUTHOR]

Vegetables have been the second largest cultivated crop after grain in China, among which leaf vegetables account for 25% of the total planting area of vegetables. Among them, seedling transplanting is one of the most important steps during planting. Automatic transplanting can be expected as an effective way to fully meet the requirement of single-plant planting of leafy vegetables. However, it is still lacking in the automatic transplanting equipment of leaf vegetables, particularly on the reliability. Two challenges remain in the application of the automatic transplanter in leafy vegetables: first, the sending and dividing seedlings are suitable for long-stem seedlings of solanocarps with developed roots, rather than broad-leaved and short-stem leafy vegetables. Second, the high accuracy of sending and dividing seedlings can lead to the low reliability of the machine and the planting efficiency. Therefore, it is urgent to explore raising seedlings, conveying and separating suitable for the automatic transplanting of leafy vegetables, in order to improve the mechanical planting level of leafy vegetables. In this study, a combined conveying and separation device was designed with the conveyor belt and stop pin for the cabbage substrate block seedlings, particularly for the high success rate and low injury rate of automatic conveying and separating of leafy vegetables. Combined with the mechanical properties of cabbage substrate block seedlings, the theoretical analysis was carried out to determine the stable conveying and separating conditions of the conveying and separating device and the working parameters of the key mechanism. The test bench was built for the single-factor test to determine the range of key factor parameters. The front conveyor belt motor speed, rear conveyor belt motor speed, and frequency of the stop pin were selected as the main test factors. The Box-Behnken central composite test was carried out with the success rate of seedling separation and the substrate block breakage rate as the evaluation indexes. The second-order regression model was established to clarify the influence of various influencing factors on the indexes. The results showed that the better performance of conveying and separating was achieved, when the motor speed of the front conveyor belt was 104 r / min, the motor speed of the rear conveyor belt was 75 r/min, and the frequency of the stop pin was 1.85 s per time. The success rate of seedling separation was 92.73%, and the damage rate of the substrate block was 4.09% in the bench verification test. The success rate of seedling separation was 91.81% and the damage rate of the substrate block was 4.62% in the field verification test. The error values of the two verification tests and the optimization were less than 2 percental points, indicating the high stability. This finding can provide a strong reference for the design of automatic vegetable transplanting equipment. [ABSTRACT FROM AUTHOR]

Tissue culture rapid propagation cannot be reduced the production that is caused by environmental factors, compared with traditional flower cultivation. Since phalaenopsis flowers are very popular for their unique appearance, tissue culture rapid propagation can be expected to cultivate phalaenopsis for the high cultivation speed in industrial production. Current phalaenopsis rapid propagation cannot fully meet the large-scale production in recent years, due to the high repetition and labor consumption. Therefore, it is in high demand for automated phalaenopsis tissue-cultured seedlings' rapid propagation. Among them, image recognition can be used to detect the picking points of seedlings in the process of the robot arms. However, current algorithms of image recognition are only applicable to the specific growth stages, due to the differences in the image characteristics of seedlings at different stages. This study aims to improve the adaptability and efficiency of seedling grasping point detection. A seedling grasping point localization was also proposed using the improved U2-Net salient detection network (MBU2-Net+). A seedling grasping end effector was then designed. The overall steps of seedling grasping included visual detection, grasping point localization, and a robotic arm control module. Firstly, industrial cameras were used to capture the images of seedlings. The salient map of the seedlings was obtained after the MBU2-Net+ salient detection network. Secondly, the salient map was processed by filtering, while the skeleton extraction was to extract the intersection points of the skeleton lines. Then, the intersection points were clustered using K Nearest Neighbours (KNN) to remove the salient outliers. The grasping angle was obtained to locate the seedling grasping point using morphological analysis after fitting the line using Random Sample Consensus (RANSAC). Finally, the grasping point location data was sent to the robotic arm for grasping. The salient detection experiment was carried out to compare MBU2-Net+ with Res2Net-PoolNet, U2-Net, and U2-Net+. The average absolute error of MBU2-Net+ was 0.002, the maximum F1 score was 0.993, the FPS was 33.99, and the model weight size was 2.37MB. All of these metrics were optimal. The success rate of grasping point detection of 112 seedlings in four groups was 85.71% in the grasping point of seedling detection experiment using MBU²-Net+. The failure of grasping point extraction was attributed to the complex structure of certain seedlings, indicating a significant number of mature leaves and roots. Consequently, the intersections in the obtained skeleton image deviated significantly from the actual locations of roots or leaves, leading to grasping points out of the appropriate regions. Six seedlings were selected to verify the adaptability from the mother bottle to the intermediate bottle stage, three seedlings from the intermediate bottle to the daughter bottle stage, and two virtual seedlings in the rapid propagation process of phalaenopsis. The overall success rate was 81.82%. A high success rate was achieved to extract the grasping points for the orchid seedlings in the entire process of orchid tissue culture. Furthermore, a certain level of generalization was suitable for the other types of seedlings with similar structures. In summary, the capability of the improved model can be expected to effectively identify the grasping points for the orchid seedlings in the entire process of orchid tissue culture, even with the limited datasets. The adaptability and efficiency were significantly enhanced to detect the grasping points for new seedlings. The findings can serve as a technical reference in the development of automated and rapid propagation techniques for tissue-cultured seedlings. [ABSTRACT FROM AUTHOR]

Polygonatum kingianum is one of the most valuable Chinese medicinal materials. Because of the increasing planting area, anthracnose has become a limiting factor affecting the production of P. kingianum in recent years. In this study, 12 putative diseased samples of P. kingianum were collected from Xundian County, Kunming City, Yunnan Province and the fungal isolates were isolated fromsymptomatic leaf tissues. All the isolates were identified by the morphology, multigene sequences (ITS, ACT, CAL, CHS-1, GAPDH and TUB2) and pathogenicity tests. The results showed that Colletotrichum fructicola is the main causal agent of the anthracnose of P. kingianum in Xundian County. Furthermore, the inhibitory activity of 10 plant-derived compounds on C. fructicola was evaluated by plate fumigation or medicated medium methods. The results indicated that α-terpineol, 4-terpineol and carvacrol had significant inhibitory effects on C. fructicola, with EC50 values of 54.26, 81.74 and 94.78 μL/L, respectively. The results provided a theoretical basis for the green prevention and control of anthracnose of P. kingianum. [ABSTRACT FROM AUTHOR]

This study aims to investigate the effects of simulated nitrogen (N) deposition on the photosynthesis of Quercus mongolica in Shulan, Jilin Province.The N addition gradient was designed to three levels: blank control(CK, 0 kg·hm-2·a-1), low N addition(LN, 50 kg·hm-2·a-1), and high N addition(HN, 100 kg·hm-2·a-1). The results revealed different response mechanisms of Q. mongolica seedlings to three N addition levels. It was found that the net photosynthetic rate (Pn) of Q. mongolica seedlings increased under LN treatment and decreased under HN treatment. Compared with the CK treatment, the height and ground diameter of Q. mongolica seedlings under LN treatment increased by 8.68% and 23.34% respectively, and the chlorophyll content increased by 13.17%. Under the HN treatment, the stomatal conductance (Gs) decreased by 37.81% compared with the LN treatment, and the maximum rate of carboxylation and maximum rate of electron transport of Q. mongolica seedlings decreased significantly compared with the CK and LN treatment (P＜0.05. In general, the LN treatment promoted seedling growth and improved the photosynthetic productivity (G) of seedlings by increasing chlorophyll content and Pn of leaves. The HN treatment decreased the Gs and the electron transfer ability of the photosystem, weakened the Pn of leaves, and inhibited the G of seedlings, which was not conducive to seedling growth. More [ABSTRACT FROM AUTHOR]

To investigate whether litter of Caragana korshinskii Kom, Carex and Poplus had substances that inhibit the seed germination and seedling growth of Pinus sylvestris var.mongolica, and to study the obstacles of natural regeneration in artificial forests, petri dish bioassay and pot experiment were adopted, the concentrations of the extracts were set at 1:50, 1:250, 1:500 and 1:1 000, and one-way ANOVA and least significant range method were used to explore the effects of the three types of extracts on seed germination and 2-year old seedlings. Results showed that: 1) In the seed germination experiment of Pinus sylvestris var. mongolica, when the concentration was 1:50, the extract of Caragana korshinskii Kom exhibited significant inhibition on germination percentage, germination potential, germination index, radicle and cotyl, which were significantly lower than those of the control by 24.14%, 50%, 36.03%, 23.23% and 27.53%, respectively, while the other three concentrations had no significant effect. The Poplus litter extract had significant inhibitory effect on the other four indexes except germination potential, which were significantly lower than the control by 34.48%, 54.79%, 47.70%, 51.24%, respectively, while the other three concentrations had no significant effect. Carex litter extract could promote the other four indexes except germination index, but the effect was not significant. With the decrease of the concentration of Caragana korshinskii Kom branches and Poplus litter extract, the inhibitory effect was weakened, even disappeared or changed to promoting effect.2) In the pot experiment of 2-year old seedlings of P.sylvestris var. mongolica, when the concentration was 1:50, Caragana korshinskii Kom extract to the seedling height, ground diameter, fresh weight, biomass and average root diameter were significantly lower than those of the control by 82.30%, 86.11%, 27.40%, 52.78% and 10.53%, respectively, while the other three concentrations had no significant effect on them. When the concentration of Poplus litter extract was 1:50, the seedling height, ground diameter, aboveground biomass, biomass, root total length and root surface area were significantly lower than those of the control by 76.11%, 83.33%, 48.91%, 53.70%, 39.40% and 43.55%, respectively, while the other three concentrations had no significant effect on them. Different concentrations of Carex extract had no significant effect on it, but showed a certain promotion effect on the whole. The extracts of Caragana korshinskii Kom branches and Poplus litter exhibited ‘low inhibition and high promotion' on seed germination and seedling growth of P. sylvestris var. mongolica, while Carex litter extract promoted the growth of 2-year-old seedlings of P. sylvestris var. mongolica on the whole [ABSTRACT FROM AUTHOR]

[Objective] The light condition is one of the key factors that affect the tissue culture efficiency of Anthurium andraeanum. The effects of different LED light quality ratio and light intensity on different stages of A. andraeanum tissue culture were studied to explore these light conditions suitable for each stage of tissue culture of A. andraeanum and provide an important technical reference for efficient tissue culture of A. andraeanum. [Method] The new A. andraeanum cultivar Fuxing was used as the experimental material, and the effects of different proportions of red and blue LED light ratio and light intensity on callus induction, proliferation culture and strong seedling culture of A. andraeanum Fuxing were analyzed. [Result] The LED red light quality was more suitable for the callus induction of A. andraeanum Fuxing, the 10% R light quality condition with light intensity of 100 lx had the highest callus induction rate of 79.58%, and the callus mass was yellow-green, compact, large in volume and good in state, which was suitable for the callus induction of A. andraeanum Fuxing leaves. The light quality ratio of R ∶ B = 3 ∶ 1 was suitable for callus proliferation culture of A. andraeanum Fuxing, and the proliferation coefficient was the highest (6.44) when the light intensity was 600 lx. Compared with WL light conditions, R ∶ B = 4 ∶ 1 light quality ratio was more suitable for the callus bud differentiation culture of A. andraeanum Fuxing, when the light intensity was 1 000 lx, the number of callus proliferation and differentiation was 19.44, and the buds were short and strong with good growth potential, without yellow leaf phenomenon. The light quality ratio suitable for the tissue culture seedling culture of A. andraeanum Fuxing at the strong seedling stage was R∶B = 4∶1, the light intensity was 900 lx, the number of roots of the strong seedlings of was more, with an average of 5.67, the plant height was 2.88 cm, the stem diameter was 1.44 mm, the leaf length was 11.69 mm, the leaf width was 8.54 mm, the plant leaf was large, the SPAD value was 39.23, the chlorophyll content of the leaf was higher, and the overall growth of the plant was robust without yellow leaf phenomenon. [Conclusion] LED light conditions have an impact on callus induction, proliferation culture, and strong seedling culture of A. andraeanum Fuxing in tissue culture. According to the lighting requirements at different stages of A. andraeanum tissue culture, selecting appropriate LED light quality ratio and light intensity conditions can effectively improve the callus induction rate, proliferation rate and tissue culture seedling production quality of A. andraeanum in tissue culture, and provide technical support for the efficient and standardized production of new A. andraeanum cultivar Fuxing. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the effects of Pb deposited from the atmosphere on the growth and Pb accumulation characteristics of eggplant (Solanum melongena L.) seedlings. A potted planting simulation test was carried out using eggplant as the test crop. The effects of precipitated Pb on seedling growth and its accumulation and migration characteristics within the eggplant were studied by adding PbS, PbSO4, and PbO2 solution to the surface of the leaf and soil. The results showed that both leaf and soil surface settling Pb stress could increase the Pb content of eggplant seedlings. The migration rate of Pb from the leaf to the seedling was PbS (87.01%) >PbSO4 (50.78%) >PbO (2 50.44%) . The migration rate of Pb from leaf to stem was lower than 2%. Pb primarily accumulated in the eggplant leaves. PbO2 settling on leaves decreased the stomatal conductance and dry mass of the eggplant seedlings, but PbS and PbSO4 did not significantly affect their growth (P<0.05) . The migration rate of Pb deposition from the soil surface to the eggplant seedlings was lower than 1%, which had no significant effect on their growth. Under atmospheric Pb deposition stress, small particle Pb was more likely to enter the plant from the leaf surface, and ionic Pb was more likely to migrate into the plant body. Leaf Pb deposition contributed more to Pb accumulation in the eggplant than soil surface Pb deposition. [ABSTRACT FROM AUTHOR]

To deepen our understanding of the role of the microhabitat in seedling colonization, we analyzed the relationship between microhabitat factors and the natural renewal seedling traits of 1-year-old Tianshan spruce (Picea schrenkiana var. tianschanica) seedlings in the central northern slope of the Tianshan Mountains. In addition, we explored the influence of microhabitat factors on seedling traits via ranking analysis. Our results identified 11 microhabitat factors, namely, litter thickness, soil compaction, herb height, herb cover, moss cover, litter cover, altitude, root disc layer thickness, soil weight, soil phosphorus, and soil volume, that significantly affected the seedling traits of natural-regenerated 1-year-old Tianshan spruce seedlings. These factors explained 56.01% of seedling variation, with litter thickness, moss cover, soil compaction, and soil weight accounting for 55.13%. During the natural renewal colonization of Tianshan spruce, the type of ground cover and degree of soil loosening had a strong impact on the traits of 1-year-old seedlings. [ABSTRACT FROM AUTHOR]

【Objective】The present paper aimed to analyze the effects of endophytic fungus Y118 on the growth promotion and quality of its host, Zanthoxylum nitidum（Rox.） DC,so as to provide a reference for improving comprehensive benefits of Z.nitidum.【Method】Z.nitidum plants were cultured with endophytic fungus Y118 solid fermentation medium.The growth indexes（fresh weight, plant height, stem base width, stem middle width and fresh and dry weight of roots, stems and leaves） of Z.nitidum plants were measured at different growth stages.The contents of nitrine chloride and chelidonine in roots of Z.nitidum were determined by chromatographic method.【Result】After 3 months of culture, the fresh weight, plant height, stem base width and stem middle width of the fungus Y118 treatment group were 34.76 g, 34.47 cm, 6.54 mm and 4.25 mm, respectively, which were extremely significantly higher than those of the control group（P＜0.01,the same as below）.The fresh weight and dry weight of roots, stems and leaves were significantly increased（P＜0.05,the same as below） or extremely significantly increased.After 6 months of culture, the fresh weight and plant height of Z.nitidum were 68.33 g and 47.85 cm, respectively, which were extremely significantly higher than control group. The fresh weight and dry weight of roots, stems and leaves were extremely significantly increased. After 9 months of culture, the fresh weight, plant height and stem base width of Z.nitidum treated with fungus Y118 were 73.80 g, 49.22 cm and 9.79 mm, respectively, which were extremely significantly higher than those of the control group. The fresh weight and dry weight of roots, stems and leaves were extremely significantly increased. After 12 months of culture, the fresh weight of Z.nitidum in Y118 treatment group was 78.71 g, which was extremely significantly higher than control group, and the fresh and dry weight of root, stem and leaf were significantly increased or extremely significant. After 9 and 12 months of co-culture, Z.nitidum alkali content in fungus Y118 treatment group was 0.783 and 0.904 mg/g, respectively, which increased by 42.11% and 44.18% compared with the control group. The content of chelidonine at 9 and 12 months of co-culture were 3.704 and 4.201 mg/g, respectively, which increased by 40.73% and 26.57% compared with the control.【Conclusion】Inoculation of endophytic fungus Y118 could significantly or extremely significantly increase the fresh weight, plant height, stem base width and stem middle width of Z.nitidum seedlings, which was beneficial to promote the growth and development of Z.nitidum seedlings, and could improve the fresh and dry weight and quality of roots, stems and leaves. It can provide the basis for the field production test of Z.nitidum. [ABSTRACT FROM AUTHOR]

Compared with other tea ports in China, Ningbo, as "the starting place of Maritime Tea Road", had a special position and played an important role in the process of tea’s spreading to the world. This process started early, lasted a long time and had great influence. It mainly disseminated to East Asia starting from the Tang and Song dynasties. Till modern times, Ningbo tea had been disseminated to India in South Asia and Georgia in Europe. The spread of Ningbo tea involved tea-leaf trade, tea seed, tea seedling and tea making technology export. The combination of these three parts of Ningbo tea spreading in different periods established its indispensable status in the process of tea spreading to the world. [ABSTRACT FROM AUTHOR]

In order to realize precision sowing of the small and medium-sized tree seeds, which with brittle and hard shell, irregular shape and low sphericity, a precise seeder which based on blowing-vibration and match seedling trays was designed. Taking Pinus sylvestris var. mongolica seed for example, the application of indentation method, inverse analysis algorithms, the Hertz-Mindlin method which from EDEM as model were used to explore the mechanical properties and establish the population spatial configuration model of seed. Based on this, SolidWorks was applied to design the structure of the seeder. The seeder was mainly composed of pneumatic system, electronic control system, seedling trays, seeding mechanism, seeds supply mechanism, punch mechanism, seedling trays conveying mechanism and so on. The seeds supply system was supported by blowing-vibration device, which could make seeds group effective separation and flow, keep the seeds movement state such like “boiling”, ensure that the seeds can be relatively stable in the effective seed suction position during the seed adsorption, so as to improve the adsorption success rate of the equipment. Through sowing experiment, when the vibration frequency of trays was 20 Hz, vibration amplitude was 5 mm, and running speed of trays conveying mechanism was 0. 045 m/ s, the cavity rate was the lowest 1. 74%, repetitive seeding rate was 0. 26% while the qualified rate of sowing was 98%, the sowing efficiency was 300 tray/ h. The precision seeder which have strong versatility can match hard conventional seedling trays and paper alveolate seedling trays. [ABSTRACT FROM AUTHOR]

Strawberry is one of the photophilous plants, light has great influence on the growth and development of strawberry. In order to explore the effects of different light quality on the growth and physiological characteristics of strawberry seedlings, in this study, agricultural transparent film(used as the control), red film, purple film, yellow film, and blue film were used to simulate different light quality to treat strawberry seedlings. The biological traits, physiological characteristics, and photosynthetic characteristic indexes of strawberry seedlings under different light quality treatments were measured. The biological traits were chlorophyll content, plant height, stem diameter, petiole diameter, leaf width, leaf length, and petiole length. The physiological characteristics were root activity, mineral content, soluble sugar content, and soluble protein content. The photosynthetic characteristic indexes were net photosynthetic rate(Pn), stomatal conductance(Gs), transpiration rate(Tr), intercellular CO2 concentration(Ci). The results showed that the plant height, stem diameter of strawberry seedlings under the blue film treatment were 21.2 cm and 1.37 mm which were significantly hiher than those under other light quality treatments. The leaf length and leaf width of strawberry seedlings under yellow film treatment increased, and they were 7.1, 12.0 cm, respectively, and the petiole was 0.32 mm. Moreover, the root activity of strawberry seedlings treated with yellow film was strong(60.04 mg/(g·h)) which was 69.9% higher than that in the control. The content of soluble sugar and soluble protein of strawberry seedlings treated with yellow film increased and was 86.4% and 1.8% higher than that in the control, and the content of majorelement nitrogen increased and was 37.31 mg/g. Under the treatment of red film, the content of phosphorus and potassium was higher than that in the control. The content of Ca, Fe, Mn, Cu, and Zn was significantly 34.7%, 88.9%, 98.9%, 48.8%, and 120.0%, respectively, higher than that in the control. The content of chlorophyll a of strawberry seedlings treated with yellow film was high and 34.98 mg/g, the net photosynthetic rate, stomatal conductance, and transpiration rate of leaves were significantly higher than those in the control, increased 11.2%, 20.0%, and 14.8%, respectively. Therefore, yellow film could be used as the greenhouse film to promote the growth and development of strawberry seedlings. [ABSTRACT FROM AUTHOR]

Ascertaining the safe sowing date of double-cropping early rice and the change rules of spring climate resources is an important basis for improving use efficiency of spring climate resources and agricultural production efficiency. Based on the daily average temperature data of 79 national meteorological stations in Jiangxi from February 1st to April 30th during the past 30 years (1992-2021), the distribution of safe sowing dates with 50% and 80% guarantee rates of double-cropping early rice with different seedling raising methods in Jiangxi under climate warming were systematically analyzed. The results showed that both average temperature and average pentad temperature increased significantly from 1992 to 2021, the climatic trend rates of average temperature was 0.055 °C·y-1, the most significant periods of climatic mean temperature increase were mainly concentrated in the 5th and 6th pentads in February, the 4th, 5th and 6th pentads in March and the 1st pentad in April, all above 1.5°C. The safe sowing dates of film-mulching dry seedlings, film-mulching wet seedlings, and direct seeding all shown a significant trend in advance, and the advance range from large to small is film-mulching dry seedlings> film-mulching wet seedling> direct seeding. Compared with the traditional sowing time, the safe sowing date of film-mulching dry seedlings in northern and central Jiangxi can be advanced to the end of early March, and which can be advanced to early March in the southern Jiangxi; the time of film-mulching wet seedlings in northern Jiangxi can maintain the traditional sowing date or be advanced to the early of late March, and in the central and southern Jiangxi this time can be advanced to the end of middle March; the time of direct seeding in northern and central Jiangxi can be advanced to 2-3 days before Qingming festival, and in the southern Jiangxi this time can be advanced to the end of late March. [ABSTRACT FROM AUTHOR]

To study the effects of titanium dioxide nanoparticles (TiO2 NPs) on plant toxicity, uptake, and distribution of cadmium (Cd), a pot-culture experiment was conducted from May to July 2020. The effects of different concentrations of TiO2 NPs（0, 50 mg·kg-1, and 200 mg·kg-1)and Cd (0, 2, 10 mg·kg-1, and 50 mg·kg-1) on growth, chlorophyll content, antioxidant enzyme activity, and Cd uptake in maize seedlings were investigated. The results showed that the application of 200 mg · kg-1 TiO2 NPs significantly (P<0.05) increased the dry weight of maize seedlings under 50 mg·kg-1 Cd stress. When the Cd concentration was 50 mg·kg-1, the exogenous addition of 200 mg·kg-1 TiO2 NPs significantly (P<0.05) enhanced chlorophyll a and b content by 42.48% and 35.55%, respectively. Under the co-exposure of Cd and TiO2 NPs, with the increase in TiO2 NPs concentration, the activities of SOD, APX, and POD gradually increased. When the concentration of Cd was 10 mg·kg-1, treatment with 50 mg·kg-1 TiO2 NPs significantly increased the translocation factor and the extraction amount of Cd. The results show that TiO2 NPs could be used to enhance the phytoremediation of Cd-contaminated soil. [ABSTRACT FROM AUTHOR]

The effects of the interaction of light intensity and acid rain on the growth and biomass distribution of Schima superba seedlings were studied under three light conditions[100% natural light（L1）, 50% natural light（L2）, and 20% natural light（L3）] and three acid rain gradients [severe acid rain（pH 2.5, A1）, moderate acid rain（pH 4.0, A2）, and mild acid rain（pH 5.6, A3）]. Seedlings grown at pH 7.0（ACK） were used as the control. The results after 150 d of stress were as follows: light intensity had a very significant effect（P＜ 0.01）on the height and ground diameter of S. superba seedlings, whereas acid rain had a significant effect（P＜0.05） only on the ground diameter. There was no significant effect of the interaction between light intensity and acid rain on the seedling height and ground diameter. Light intensity had a significant impact（P＜0.01） on the biomass of each organ of the seedlings. Shading inhibited overall seedling growth. Whereas acid rain had a significant effect（P＜0.01） only on the leaf and stem biomass. Additionally, light intensity and acid rain had a significant（P＜0.05） interaction on leaf biomass, however, there was an extremely significant（P＜0.01） interaction effect on stem biomass. The severe acid rain（A1） gradient significantly decreased the stem biomass of seedlings by 48.8%, 13.8%, and 32.2% and increased the leaf biomass by 24.4%, 37.0%, and 7.6% under L1, L2, and L3, respectively, compared to the control. Light intensity and acid rain, as well as their interactions, had significant impacts（P＜0.01） on the stem-to-weight and stem-to-root ratios. The inhibitory or promotive effect of acid rain depends on the light environment, pH value, and the seedling organs. The promotive effects of acid rain were noticeable under moderate shade conditions. [ABSTRACT FROM AUTHOR]

The tomato variety "Fenguan" was used in a control experiment in a Nanjing University of Information Science and Technology experimental greenhouse from December 2019 to April 2020. Continuous light supplementation for 300min was used as the control treatment (CK). Treatment 1 (L1) was supplemented with light twice a day for 150min each time at an interval of 120min. Treatment 2 (L2) was supplemented with light 3 times a day for 100min each time and 2 times at 60min intervals. Treatment 3 (L3) was supplemented with light 4 times a day for 75min each time and 3 times at 40min intervals. Treatment 4 (L2) was supplemented with light 5 times a day for 60min each time and 4 times at 30min intervals. Photosynthetically active radiation was 600µmol⋅m-2⋅ s -1. The chlorophyll content, photo synthetic parameters, kinetic parameters of rapid fluorescence induction, and spectral characteristics of tomato seedling leaves were measured under supplementary light at different intervals. The results showed that (1) the increase in the frequency of light supplementation interval could promote the synthesis of some pigments in the leaves of tomato seedlings. At 36 days of treatment, chlorophyll-a content was 16.3% higher and carotenoid content was 19.6% more in the L4 treatment than in CK. (2) The three red-edge parameters λred, Sred, and Dred of tomato leaves under intermittent light supplementation showed a typical "redshift" phenomenon with increasing interval frequency, but the chlorophyll changes of leaves differed from the spectral pattern at the early stage of light supplementation. (3) The light saturation point (LSP), apparent quantum efficiency (AQE), and light compensation point (LCP) of tomato seedling leaves under prolonged intermittent light supplementation were higher than those of the continuous light treatment, and the higher interval frequency, the higher the net photosynthetic rate and the greater the photosynthetic capacity. However, tomato leaf stomata exert a delayed effect on light fluctuations, and stomatal delay alters the light capture process of leaf photosynthesis while limiting the transpiration and carbon exchange processes of stomatal movement. (4) The effect of intermittent light supplementation on the energy partitioning of PSII reaction centers showed a short-term reduction in the maximum photochemical efficiency of leaves, with an increase in the quantum yield captured by the reaction center (φPo) and for electron transfer (φEo) and a decrease in the quantum ratio for heat dissipation (φRo) when the number of treatment days increased, with a greater change at L4, where φPo decreased at L4 compared to CK at treatment day decreased by 3.8% at day 9 and increased by 11.6% at day 36, and φRo increased by 4.8% at L4 treatment and decreased by 6.9% at day 36 compared to CK at day 9 of the treatment. [ABSTRACT FROM AUTHOR]

【Objective】The effects of five species of ectomycorrhizal fungi on the growth, root structure and nutrient uptake of Pinus massoniana Lamb. seedlings after persistent drought and re-watering are studied, and the best mycorrhizal seedlings are screened to provide a scientific basis for drought-resistant cultivation and reforestation of P.massoniana Lamb.【Method】Masson pine seedlings were used as hosts to inoculate with Suillus luteus, Suillus luteus 1, Cantharellus cibarius, Pisolithus tinctorius and Cenococcum geophilum. Taking the uninoculated seedlings as the control（CK）, by greenhouse potted method, the inoculated and uninoculated seedlings were subjected to continuous drought treatment for 7 d, 14 d, 21 d, 28 d, 35 d and water treatment after continuous drought for 14 d, 21 d and 28 d, then the growth, root structure and nutrient absorption of seedlings were compared and analyzed.【Result】 Under the condition of continuous drought, the seedling height, ground diameter, root length, root thickness, lateral root length, lateral root number, and root volume of the strain were significantly higher than those of the control, and the seedling biomass and nutrient （N, P, K） contents all increased at first, and then decreased, and reached the maximum value of stress on the 21st day; among the five mycorrhizal seedlings, the effect of inoculating S.luteus 1 was the best. Compared with CK, the seedling height and ground diameter increased by 37.8% and 36.5%, the biomass increased by 48.3%, the root length, root thickness, lateral root length, lateral root number and root volume increased by 67%, 45%, 204%, 122%, 450%, respectively, and the contents of N, P, and K increased by 129%, 111%, 212%, respectively. The recovery ability of mycorrhizal seedlings after rewatering was significantly higher than that of CK. Rewatering after mild to moderate drought stress（14-21 d） was beneficial to the growth and development of the root system of mycorrhizal seedlings, and severe drought stress（28-35 d） caused certain damage to the seedlings of P.massoniana Lamb., and it was difficult to recover after rehydration; after rehydration, S.luteus 1 significantly promoted the growth of the root length and the number of lateral roots of the seedlings, and reached the maximum after 14 days of stress, with an increase of 59.6%., 23.5%.There was a significant positive correlation between the biomass and P content of seedlings after continuous drought and rehydration.The biomass of masson pine mycorrhizal seedlings after inoculation with P.tinctorius was significantly positively correlated with root length and lateral root length >5 cm. 【Conclusion】 Ectomycorrhizal fungi increases the biomass of seedlings, promote root growth and nutrient absorption, and increases the stress resistance of seedlings after continuous drought and rehydration. Mycorrhizal seedlings by inoculating S.luteus 1 should be selected in mildly arid regions, which could improve the survival rate of afforestation and increase the adaptability of seedlings to drought. [ABSTRACT FROM AUTHOR]

Weeds have been one of the main factors to affect the growth of crops in the seedling stage. Timely weeding is a necessary measure to ensure crop yield. An intelligent field weeding equipment can also be a promising potential deployment in the unmanned farm system at the current stage of intelligent agriculture. Effective recognition of crops and weeds has been a high demand to promote the development of intelligent weeding equipment. Previous research was focused mainly on object detection and semantic segmentation using deep learning. A great challenge is still remained in the performance of target detection, in the case of overlap images between the crops and weeds under the complex field. The reason was that the different target areas cannot be further divided when the generated anchor box overlaps in a large area. The pixel level annotation can also be required to train the semantic segmentation, where the data samples cannot be easy to obtain. The weak real-time performance cannot be conducive to practical application. In this study, an improved model was proposed using shifted window Transformer (Swin Transformer) network, in order to enhance the accuracy and real-time performance of crop and weed recognition. The specific procedure was as follows. 1) A semantic segmentation model of corn was established for the real and complex field scene. The backbone of the model was the Swin Transformer architecture, which was denoted by Swin-Base. The full self-attention mechanism was also adopted to significantly enhance the modeling ability in the Swin Transformer using the shift window division configuration. Self-attention was then calculated locally in the non-overlapping window of the segmented image block, where the cross-window connection was allowed. The computational complexity of the backbone presented a linear relationship with the image size, thereby elevating the inference speed of the model. The hierarchical feature representation was constructed through the Swin Transformer for the dense prediction of the model at the pixel level. 2) The Unified perceptual parsing Network (UperNet) was used as an efficient semantic segmentation framework. Among them, the feature extractor was the Feature Pyramid Network (FPN) using the Swin Transformer backbone. The multi-level features obtained by Swin Transformer were used by the FPN to represent the corresponding pyramid level. An effective global prior feature expression was added in the Pyramid Pooling Module (PPM). Better performance of semantic segmentation was achieved using the fusion of the hierarchical semantic information. The Swing transformer backbone and UperNet framework were combined into one model through the Decoder-Encoder structure, denoted by Swin-Base-UN. 3) The structure of the Swin-Base backbone was improved to enhance the inference speed. The number of network parameters and calculation cost were reduced to decrease the number of hidden layer channels, headers, and Swin Transformer blocks. Therefore, four improved models were generated, including the Swin-Large-UN, Swin-Small-UN, Swin-Tiny-UN, and Swin-Nano-UN. The model size and computational complexity of improved models were about 2, 1/2, 1/4, and 1/8 times of Swin-Base-UN, respectively. 4) Taking the segmentation of corn morphological region as the case study, an improved image morphological processing combination was established to recognize and segment all the weed regions in real time. The segmentation of corn was also used to segment the weeds. The weed pixel annotation was removed from the training data of the model. As such, a large number of annotation data at the pixel level was obtained in the semantic segmentation of the improved model, compared with the original one. A comparison was made on the performance of all models in training, validation, and testing. Consequently, the Swin-Tiny-UN was determined as the best model to achieve the optimal balance between accuracy and speed. Specifically, the mean Intersection over Union (mIoU) and mean Pixel Accuracy (mPA) on the test set were 94.83% and 97.18%, respectively, which increased by 3.27 and 4.71 percentage points, respectively, compared with the RestNet-101-UN using traditional Convolutional Neural Networks (CNN) backbone. The inference speed of the model was achieved by 18.94 frames/s. The best model of semantic segmentation was superior to the traditional one, in terms of the region segmentation accuracy, pixel recognition accuracy, and inference speed. The image segmentation showed that the improved model can be expected to accurately recognize and segment maize and weeds in complex field scenes. The average correct detection rate of the improved model was 95.04% for the video stream data in the process of field work, whereas, the average detection time per frame was 5.51×10-2 s. Consequently, the improved model can be expected to detect the corn and weeds in the process of field work, indicating higher accuracy and real-time performance under practical application conditions. The findings can provide a strong reference for the development of intelligent weeding equipment. [ABSTRACT FROM AUTHOR]

To investigate the effects of HCO- 3 on the growth and physiological characteristics of plants under the stress of bicarbonate in karst environment. The growth, photosynthetic capacity, antioxidant enzyme activity, osmotic regulation substance content and cell membrane damage of Broussonetia papyrifera and Morus alba seedlings under three different concentrations of NaHCO3(0, 15, 30 mmol·L-1, respectively)were examined in the present study. The results were as follows:(1)Under HCO-3 treatment, the growth and photosynthetic capacity of Broussonetia papyrifera and Morus alba seedlings were significantly inhibited, accompanying the physiological responses of leaf cells to antioxidant and osmotic stress were significant. (2)The inhibitory effects of HCO-3 on the growth of Broussonetia papyrifera and Morus alba were concentration-dependent, and showed significant differences among examined concentrations(P<0.05). (3)The inhibitory effects of the growth, photosynthesis, antioxidant enzyme system and osmotic regulation system and the damage of plant cells under 30 mmol·L-1HCO- 3treatment were significantly stronger than those of 15 mmol·L-1HCO-3 treatment.(4)Under the same concentration of HCO-3, the growth, photosynthetic capacity, antioxidant enzyme activity, osmotic regulating substance content of Broussonetia papyrifera were significantly higher than those of Morus alba, and its leaf cell damage was significantly lower than that of M. alba. The results mentioned above indicate that HCO- 3 inhibits the growth, photosynthesis and resistance physiology of M. alba and Broussonetia papyrifera under bicarbonate stress, and the tolerance of B. papyrifera to bicarbonate stress is better than that of Morus alba, which means that Broussonetia papyrifera is more adaptable to the environment of bicarbonate stress. This study provides scientific support for the adaptation mechanism of Moraceae to karst environment. [ABSTRACT FROM AUTHOR]

A machine-transplanted large-pot carpet seedling has been one of the most innovative mechanical transplantings in precision agriculture. This study aims to explore the effects of seedling age and substrate soil ratio on the population quality and yield of late rice during transplanting. The optimal seedling age and substrate seedling raising technology were determined for the machine-transplanted late rice. The conventional indica-type rice (Sui Xiangnongzhan) was selected as the research object in this study. Three kinds of seedling age (25, 30 and 35 d), three kinds of composite substrate and natural soil ratio (substrate soil ratio 1∶1, 2∶1 and pure substrate) were used to clarify the effects of seedling age and substrate soil ratio on the seedling quality, machine-transplanted quality, population quality, yield, and the components of yield. The results showed that the substrate bulk density was significantly higher in the substrate soil ratio of 1:1 and 2:1 than that of the pure substrate, whereas, the water content, porosity, pH value, organic matter, and available nutrient elements were relatively lower than those of pure substrate treatment. A total porosity of 57.21% not suitable seedling growth was found in the substrate soil ratio 1:1 treatment. The available nitrogen contents were 223.62 and 331.25 mg/kg in the substrate soil ratio 1:1 and pure and substrate treatment, respectively, indicating the beyond seedling growth range. Moreover, the seedling quality performed better with the extension of seedling age, which was more conducive to the formation of strong seedlings. The seedling quality, population quality, yield, and the components of yield were relatively better in the substrate ratio 2:1 treatment, compared with the rest two substrates. The maximum rooting entwining force of 30 d seedling age was 73.19 N in the substrate ratio 2:1 treatment. A better performance was achieved in the pure substrate treatment, in terms of the planting percent, the basic seedlings number, and the pass rate of the relative uniformity of 35 d seedling age. Two treatments fully met the requirements of machine transplanting, according to the seedling missing, floating, injury, and overturning rate. The optimal seedling age of transplanting was obtained as 35 d in the substrate soil ratio of 2:1 treatment. There was a better performance in the tiller number, effective tiller number, earbearing tiller percentage, dry matter accumulation, and the harvest index of the population in each period after transplanting, compared with the short seedling age treatment. It infered that the long seedling age greatly contributed to the high yield population of machine-transplanted late rice. With the extension of seedling age, the seedling quality was better, which was more conducive to the formation of strong seedlings. An optimal grain maturity was achieved in the 35 d seedling age treatment, where the actual yield was significantly higher by 42.5% and 19.4%, respectively, compared with the 25 and 30 d treatment, and the moisture content of wet valley was significantly lower by 2.67 and 1.29 percentage points respectively. The grain maturity of 35 d seedling age treatment was better. The maximum correlation coefficient was 0.971 between the effective panicle number and the actual yield. The high yield of long seedling age treatment was attributed to the increase of effective panicle number. Therefore, the optimal seedling age and substrate seedling treatment were 35 d and substrate soil ratio 2:1 for the large-pot carpet seedlings of machine-transplanted late rice, when taking the twice chemical control. The findings can also provide a strong reference for the large-pot carpet seedling of machine-transplanted late rice in the southern double cropping rice areas, particularly for the higher level of planting mechanization. [ABSTRACT FROM AUTHOR]