Search

Assessing the condition of plants in an urban landscaping is a necessary component of monitoring urban ecosystems. Studying how the sensitivity of plants to stressful conditions and the influence of many factors on their growth and development is important for determining the suitability of using plants for urban improvement. The purpose of this study was to identify the impact of stress factors on the growth and development of Ligustrum vulgare L. (commonly called privet). The research was conducted in the city of Kyiv, where the plants are affected by significant vehicle traffic, intense insolation or excessive shade, and mechanical traumatization of plants due to plant trimming. Shoots of Ligustrum vulgare L. of different ages and under different growing conditions were used for the analysis. The research used methods of morphometry, chromatographic profiling of secondary metabolites, and statistical data processing. To analyze the morphogenesis of annual shoots, the Gaussian model was used, which accurately (R2 > 0.90) describes their growth processes. The model coefficients were used for a comparative assessment of the growth dynamics of Ligustrum vulgare L. shoots depending on the growing conditions and plant care. Correlation analysis also allowed for the identification of potential connections between the growth model coefficients and certain phenolic synthesis products. It was found that the plant trimming leads to an increase in the length of the shoots and accelerated growth of the side shoots. The obtained results may indicate that phenolic compounds, in particular chlorogenic acid, directly or indirectly affect the regulation of growth and development of shoots of Ligustrum vulgare L. in response to stress factors, such as mechanical injury. The content of chlorogenic acid positively correlates with the increase in the length of internodes, which indicates its possible role in morphogenesis. It has been established that the profiles of phenolic substances allow identification of Ligustrum plants at the species level. Principal component analysis (PCA) and cluster analyses showed that the phenolic profiles of plants depend on their growing conditions and the urban environment. The study confirms the importance of plant trimming for stimulating plant growth. The significant adaptation potential of Ligustrum vulgare L. plants confirmed the suitability of their use in urban environments. [ABSTRACT FROM AUTHOR]

The New Zealand Institute for Plant and Food Research has developed three semi-dwarfing apple rootstocks: PFR2, 4 and 5 with pest and disease resistance/tolerance. Nursery performance and flowering of ‘Scilate' and ‘Fuji Supreme' grafted onto PFR rootstocks and grown as monoaxis or biaxis trees were evaluated in comparison with ‘Malling 9' (dwarf) and ‘G.202' (semi-dwarf) at Hawkes' Bay research centre. For monoaxis ‘Scilate' trees, PFR rootstocks promoted primary, axillary and total shoot length/scion by (11–15%), (54–76%) and (22–37%), respectively compared with ‘M.9', but the same were lower by (4–11%), (25–62%) and (17–42%) compared with ‘G.202'. On PFR2 and PFR5, ‘Scilate' produced 6 axillary shoots/tree, compared with ‘M.9' (4) and ‘G.202' (7). ‘Scilate' on PFR2, 4 and 5 produced 74%, 62% and 93% of axillary shoots with moderate (30°–45°) crotch angle compared with ‘M.9' (30%) and ‘G.202' (79%). On biaxis trees, the total shoot length was higher on PFR2, 4 and 5 compared with ‘M.9', but not different from ‘G.202'. Flowering precocity was not affected by rootstocks. Overall, PFR2, 4, 5 and ‘G.202’ produced high-grade young trees expressing greater potential for early canopy development. [ABSTRACT FROM AUTHOR]

Sucrose has a significant role in promoting microtuberization in potato. It acts as a crucial modifier, influencing the growth and development of microtuber in potato. Understanding the role of sucrose in microtuberization is vital for improving potato cultivation practices and enhancing crop productivity. In this experiment, different concentrations of sucrose (3, 6, 9, 12, and 15%) were investigated to determine their effects on the microtuberization of a potato cultivar 'Sante'. The findings revealed that high concentrations of sucrose (12 and 15%) inhibited microtuberization percentage, microtuber count, and shoot growth. Tuberization percentage reached its maximum value (100%) when exposed to a sucrose concentration of 9%. The microtuber count was 2 per explant and 4.6 per vessel. However, using a 12% sucrose concentration resulted in the highest microtuber diameter (5 mm), microtuber fresh weight (120 mg) and dry weight (26 mg), and microtuber yield (FW: 752 mg; DW: 170 mg). The highest explant fresh weight (44 mg) and dry weight (9.5 mg) occurred in response to 15% sucrose concentration. Biomass allocation was influenced by sucrose concentration, with higher concentrations leading to a greater biomass allocation to the microtuber and explant, rather than the shoot. Accordingly, it can be concluded that a sucrose concentration of 12% was an optimal treatment for 'Sante' potato microtuber production. [ABSTRACT FROM AUTHOR]

White Guinea yam is a tuber crop characterized by a long growth period over the entire rainy season, which is affected by changes in rainfall patterns owing to climate change. In this study, we investigated the effects of shifting the planting date of yam seed tubers on shoot growth and tuber development, which could be a plausible measure for adapting to changes in rainfall patterns. Our results revealed that tuber enlargement in plants with different planting dates started depending on the days after planting rather than the day of the year. This indicates that day length had little effect on tuberization. The final tuber yield was rarely affected by low rainfall during the early growth stage, whereas severe yield reduction occurred when the rainfall stopped during the tuberization period. We conclude that shifting the planting date backward to adjust for delayed rainy seasons increases the risk of severe yield reduction.

Scots pine (Pinus sylvestris L.) has higher early growth rates than Norway spruce (Picea abies (L.) H. Karst.). To help efforts to understand possible reasons for this difference and identify appropriate regeneration methods, we labeled seedlings with 15N in the nursery to probe nitrogen (N) uptake and retranslocation in Scots pine and Norway spruce seedlings at both harsh and fertile sites in southern and northern Sweden. For this, 15N dilution was measured during the first two years after planting. We also examined the potential N2-fixation capacity in fine roots after 5–7 growing seasons. Use of 15N-labeled seedlings enabled clear discernment of contributions of uptake of new N and retranslocation of old N to new foliage. Scots pine seedlings had higher proportions of N derived from uptake (Ndfu) than Norway spruce seedlings, and higher growth. Scots pine seedlings were less responsive to site preparation treatments compared to Norway spruce that has a greater need for appropriate silvicultural measures to grow well. After the second growing season, the contribution of N derived from retranslocation (Ndfr) to N in new foliage had diminished to 10–20% at all except the harshest site, where both species were more dependent on Ndfr. The potential N2-fixation capacity in fine roots of the two species differed, but in both cases the contribution of N2-fixation to N-acquisition was negligible. [ABSTRACT FROM AUTHOR]

White Guinea yam is a tuber crop characterized by a long growth period over the entire rainy season, which is affected by changes in rainfall patterns owing to climate change. In this study, we investigated the effects of shifting the planting date of yam seed tubers on shoot growth and tuber development, which could be a plausible measure for adapting to changes in rainfall patterns. Our results revealed that tuber enlargement in plants with different planting dates started depending on the days after planting rather than the day of the year. This indicates that day length had little effect on tuberization. The final tuber yield was rarely affected by low rainfall during the early growth stage, whereas severe yield reduction occurred when the rainfall stopped during the tuberization period. We conclude that shifting the planting date backward to adjust for delayed rainy seasons increases the risk of severe yield reduction. [ABSTRACT FROM AUTHOR]

Enset, a perennial diploid plant from the Musaceae family, is a key crop in Ethiopia, supporting food, feed, and employment for over 25 million people. Despite the economic, social, and environmental importance of the crop, diseases like enset bacterial wilt pose a bottleneck for crop production and productivity. On the other hand, enset cultivation is started expanding to low-moisture area without basic information. Currently, experiments on enset diseases screening and stress conditions are being widely conducted using different pot size and enset varieties to overcome these issues. However, the absence of recommended pot sizes leads to use inappropriate pot sizes, affecting final results. Therefore, this experiment was conducted to determine the ideal pot size and stress-tolerant varieties by using three improved enset varieties and varying pot sizes. Results revealed significant effects of pot size on all traits and variety on most root, shoot, and corm traits tested. The interaction effect was significant only for some of the traits. Enset allocates more resources to root establishment in the first six months and then to vegetative growth. The crop can undergo normal growth for up to 10 months in small (7 L) and medium (23 L) pots and up to 14 months in large (34 L) pots without experiencing any stress. The variety Endale’s higher yield of dry corm in small pots and overall performance in pseudostem circumference may suggest resilience to stress conditions, as these are key yield determinant components. Further research is needed to validate these findings under field conditions.

The success of a new high-density apple planting depends on how fast the grower can recoup the high investment that these systems require. The right balance between vegetative growth and cropping during the early life of the planting is where tree growth is sufficient to rapidly fill the allotted space while at the same time producing high early yields. In this study we evaluated irrigation or fertigation as strategies compared with the traditional nonirrigated control to improve growth and yield of five apple scion cultivars (Mutsu, Gala, Honeycrisp, Jonagold, and Macoun) on M.9 or B.9 rootstocks over the first 5 years at Geneva, NY. Calcium nitrate at the rate of 113 kg·ha−1 N was applied to all three irrigation treatments (dissolved in water for the fertigation treatment, broadcast dry with the irrigation treatment, or broadcast dry with the nonirrigated control). Our results showed that fertigation with dissolved N and irrigation with dry broadcast N increased yield and tree growth similarly and significantly over the first 5 years of orchard establishment compared with the nonirrigated treatment with dry broadcast N. There was a significant economic benefit of irrigation or fertigation in the humid climate of New York State.

Although pruning contributes to the growth and development of new shoots, it is important to note that the growth potential and yield of tea varieties may differ after pruning due to genetic and environmental factors. In this experiment, 20 different varieties of tea plants were used to observe their potential for growth, shoot development, and other phenotypic indexes after pruning. The study aimed to determine the suitability of each variety for heavy pruning. It was concluded that there were obvious differences in tree strength and new growth after pruning of the different varieties, with 'Zhongcha 302' exhibiting the strongest growth and 'Emei Wenchun' showing the weakest growth. In order to understand the molecular mechanisms involved, a transcriptomic analysis was carried out on the two tea varieties. The results of the data indicate that the expression of CYP450 family was high in 'Zhongcha 302'. In 'Emei Wenchun', the expression of NCED was higher than that in 'Zhongcha 302'. The KEGG results indicate that pruning stimulates the expression of genes involved in phytohormone signalling and plant–pathogen interaction pathways in tea plants. The study offered scientific guidance for tea plant pruning suitability and preliminarily revealed the regulatory mechanism of new shoot growth in different tea plant varieties at the transcriptome level. [ABSTRACT FROM AUTHOR]

Shoot growth directly impacts plant productivity. Plants adjust their shoot growth in response to varying environments to maximize resource capture and stress resilience. While several factors controlling shoot growth are known, the complexity of the regulation and the input of the environment are not fully understood. We have investigated shoot growth repression induced by low ambient temperatures in hybrids of Arabidopsis thaliana Kro-0 and BG-5 accessions. To continue our previous studies, we confirmed that the Kro-0 allele of DYNAMIN-RELATED PROTEIN 3B causes stunted shoot growth in the BG-5 background. We also found that shoot growth repression was most pronounced near the apex at a lower temperature and that the cells in the hybrid stem failed to elongate correctly. Furthermore, we observed that shoot growth repression in hybrids depended on light availability. Global gene expression analysis indicated the involvement of hormones, especially strigolactone, associated with the dwarf phenotype. Altogether, this study enhances our knowledge on the genetic, physiological and environmental factors associated with shoot growth regulation. [ABSTRACT FROM AUTHOR]

During the period 2020-2022, an experiment was conducted in the experimental vineyard of the Agricultural University - Plovdiv, and four clones of the wine variety Syrah, numbered 100, 174, 470 and 524, grafted on the SO4 rootstock were selected as the study object. During the "pea size" phase, the green pruning operation – bunch thinning was applied. The shoots growth starts from the vegetation phase "first leaf appearance" and ends at the "veraison". The average duration is about 100 days, covering the period of May, June and July. It was found that the vine shoots from a clone 470 reached the greatest average length, V3 - 285, 265, 290 cm and V7 - 359, 336, and 380 cm, and those from a clone 100 were distinguished by the weakest growth, V1 - 197, 203 and 205 cm and V5 - 240, 228 and 245 cm. Differences were proven between the variants, both in the non-reduced (V1, V2, V3, and V4) and in those with reduced yields (V5, V6, V7, and V8), as after reducing the number of bunches, the length of the shoots was longer - high in all vines from the used Syrah clones. This study provides information on the relationship between the applied green pruning operation (bunch thinning) during the growing season and its effects on the vegetative growth. Balancing the vines bud load by controlling yield during the growing season is a preferred viticultural practice for increasing the grape quality. [ABSTRACT FROM AUTHOR]

Copyright of Mustafa Kemal University Journal of Agricultural Sciences / Mustafa Kemal Üniversitesi Tarım Bilimleri Dergisi is the property of Mustafa Kemal University, Faculty of Agriculture and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Surface and groundwater are both susceptible to nitrate nitrogen contamination that has emerged as an issue around the globe in past few years. The main goal of this research was to treat nitrate‐contaminated water through phytoremediation in a hydroponic system with reduced cost and also assess the root and shoot growth of plants cultivated in NFT hydroponic systems. Four different nitrate‐nitrogen concentrations (30, 60, 90, and 120 mg/L) were given to hydroponic treatment unit. The results revealed that shoot growth, root growth, leaf number, and shoot numbers were increased with increasing nutrient solution concentration. The study's findings demonstrated that the average elimination efficiencies of nitrate‐nitrogen varied from 44.5% to 88% for money plants, 30.77% to 80.66% for crotons, 42.56% to 86% for arrowhead plants, 32.03% to 72.25% for vetiver grass, 28.08% to 70% for spinach, and 38.11% to 75.5% for brinjal plants, respectively. Thus, hydroponic phytoremediation has emerged as the environmental and cost‐effective technique for diminishing and removing nitrate nitrogen from wastewater. [ABSTRACT FROM AUTHOR]

Although pruning contributes to the growth and development of new shoots, it is important to note that the growth potential and yield of tea varieties may differ after pruning due to genetic and environmental factors. In this experiment, 20 different varieties of tea plants were used to observe their potential for growth, shoot development, and other phenotypic indexes after pruning. The study aimed to determine the suitability of each variety for heavy pruning. It was concluded that there were obvious differences in tree strength and new growth after pruning of the different varieties, with ‘Zhongcha 302’ exhibiting the strongest growth and ‘Emei Wenchun’ showing the weakest growth. In order to understand the molecular mechanisms involved, a transcriptomic analysis was carried out on the two tea varieties. The results of the data indicate that the expression of CYP450 family was high in ‘Zhongcha 302’. In ‘Emei Wenchun’, the expression of NCED was higher than that in ‘Zhongcha 302’. The KEGG results indicate that pruning stimulates the expression of genes involved in phytohormone signalling and plant–pathogen interaction pathways in tea plants. The study offered scientific guidance for tea plant pruning suitability and preliminarily revealed the regulatory mechanism of new shoot growth in different tea plant varieties at the transcriptome level.

While not classified as an essential plant nutrient, silicon (Si) assimilation following exogenous Si application has enhanced the wear resistance of cool-season turfgrass. Given this beneficial supplementation of lignin by Si reported in epidermal tissue of monocotyledonous plants, our research objective was to quantify root morphology, vegetative nutrition and vigor, soil chemistry, and putting green performance in response to split applications of pelletized liming agents rich in Si and/or Ca and Mg. Field evaluation of granular liming agent treatment, 2441 kg (ha year)−1, was conducted on creeping bentgrass (Agrostis stolonifera L. cv. Penn G-2) putting green maintained in the Mid-Atlantic US. Pelletized Ca/Mg-SiO3 slag or dolomitic limestone treatments were conducted in frequent split applications and incorporated into the upper 5 cm of the rootzone. Measurements of canopy color and density, shoot growth as clipping yield, soil pH, Si and nutrient content of clippings, and soil extractable Si were performed each season. Cumulative Ca/Mg-SiO3 application (kg ha−1) increased mean acetic acid (HOAc) extractable Si by 35 to 60 mg kg−1 and leaf Si content by 1.0 to 1.5 mg g−1. However, neither putting green canopy quality, shoot nutrient concentration, 5 to 15 cm depth root length density nor ball roll distance was improved by liming agent treatment. Liming agent-treated or untreated plots showed statistical, yet inconsistent, differences in clipping yield 4, 14, 15, 16, and 17 months from initiation (MFI). This thorough shuffling of treatment rank, resulting in identical experiment-wide means precludes the expectation of dependably superior vigor by any. [ABSTRACT FROM AUTHOR]

Cytokinin is widely involved in the regulation of plant growth, but its pathway-related genes have not been reported in Moso bamboo. In this study, a total of 129 candidate sequences were identified by bioinformatic methods. These included 15 IPT family genes, 19 LOG family genes, 22 HK family genes, 11 HP family genes and 62 RR family genes. Phylogenetic analysis revealed that the cytokinin pathway was closely related to rice, and evolutionary pattern analysis found that most of the genes have syntenic relationship with rice-related genes. The Moso bamboo cytokinin pathway was evolutionarily conservative and mainly underwent purifying selection, and that gene family expansion was mainly due to whole-gene duplication events. Analysis of transcriptome data revealed a tissue-specific expression pattern of Moso bamboo cytokinin family genes, with auxin and gibberellin response patterns. Analysis of co-expression patterns at the developmental stages of Moso bamboo shoots revealed the existence of a phytohormone co-expression pattern centered on cytokinin signaling genes. The auxin signaling factor PheARF52 was identified by yeast one-hybrid assay as regulating the PheRR3 gene through a P-box element in the PheRR3 promoter region. Auxin and cytokinin signaling crosstalk to regulate Moso bamboo growth. Overall, we systematically identified and analyzed key gene families of the cytokinin pathway in Moso bamboo and obtained key factors for auxin and cytokinin crosstalk, laying the foundation for the study of hormone regulation in Moso bamboo. [ABSTRACT FROM AUTHOR]

Ginger (Zingiber officinale, Roscoe) is a tropical rhizome crop typically grown from rhizome pieces, but can also be produced from seedlings. No information is available on how the seedling method compares with the rhizome piece method in organic ginger culture. In addition, information on the growing of organic ginger in the mid-Atlantic region is lacking. Some of the challenges include limited knowledge of rhizome storage, types of propagation materials for planting in the field or high tunnel, and acceptable organic fertilizers that will not increase the excess P currently polluting the Chesapeake Bay watershed. The objective of this study was to assess plant development, soil nutrients, and economic feasibility of organic ginger derived from different storage conditions and planting materials when grown in different nutrient sources in a high tunnel. Three types of plant material (single-shoot transplant seedlings derived from 36.5–40.0 g/rhizome, multishoot transplant seedlings derived from 60–120 g/rhizome, and rhizome seeds of 60–120 g) and three fertilizers types [cotton seed meal, 6N–0.9P–0.8K (0.18 kg⋅m–2), plus AZOMITE (1 kg⋅m–2); Nature Safe, 13N–0P–0K (0.07 kg⋅m–2); and Phytamin All Purpose Liquid fertilizer, 4N–1.3P–3.3K (0.26 L⋅m–2)] were used in 2018. In 2019 and 2020, three types of plant material and two fertilizer types at modified rates from the 2018 study, plus two storage containers (pans and flats), were tested. In general, the rhizome storage container did not affect plant height, leaf soil plant analysis development (SPAD) index, and rhizome yield, and its effect on tillers was none or mixed. Fertilizer type had mixed effects on plant height and tiller number, and no effect on the leaf SPAD index. Rhizome yields in 2019 and 2020 were unaffected by fertilizer, but Nature Safe produced a greater benefit-to-cost ratio (BCR) and profitability index (PI) than Phytamin. Soil P was generally less in Nature Safe–fertilized soil than in Phytamin-fertilized soil. Multishoot seedlings produced the greatest rhizome yield, BCR, PI, and tallest plants, and had some of the highest tiller numbers. These findings show that it would be more profitable to use multishoot seedlings as planting material in high tunnels compared with single-shoot seedlings and rhizome seeds. Furthermore, the lower P levels in the Nature Safe–fertilized soils compared with the Phytamin soils, and greater PI suggest that using Nature Safe will be a better choice than Phytamin for growing organic ginger.

Reduction of water availability imposes the agronomic issues of increasing the storage capacity of the soil and improving the use of rainwater or irrigation water. A field experiment in 2021 was conducted in a 5-year-old peach orchard in a Mediterranean environment to study the effect of mixed composed amendments (ACM), applied in different amounts, on the dynamics of soil water status. Water balance was monitored during the peach vegetative reproductive cycle on a daily scale. Three treatments of mixed composed amendments (ACM) were compared: A0, control; A1, with amendment (10 t ha−1); and A2, with half dose of amendment (5 t ha−1). On a seasonal scale, soil water content increased by 27% and 33% in A1 and A2 compared to A0, while relative extractable water varied between 0.41 (A0) and 0.65 (A1 and A2). Both soil water balance indicators show that storage capacity increases with the addition of amendment. Improved soil storage capacity was associated with higher values of stem water potential (throughout the growing season) and stomatal conductance (at the end of the season). Shoot and fruit growth observations were consistent with soil water content dynamics. [ABSTRACT FROM AUTHOR]

Ginger (Zingiber officinale, Roscoe) is a tropical rhizome crop typically grown from rhizome pieces, but can also be produced from seedlings. No information is available on how the seedling method compares with the rhizome piece method in organic ginger culture. In addition, information on the growing of organic ginger in the mid-Atlantic region is lacking. Some of the challenges include limited knowledge of rhizome storage, types of propagation materials for planting in the field or high tunnel, and acceptable organic fertilizers that will not increase the excess P currently polluting the Chesapeake Bay watershed. The objective of this study was to assess plant development, soil nutrients, and economic feasibility of organic ginger derived from different storage conditions and planting materials when grown in different nutrient sources in a high tunnel. Three types of plant material (single-shoot transplant seedlings derived from 36.5-40.0 g/rhizome, multishoot transplant seedlings derived from 60-120 g/rhizome, and rhizome seeds of 60-120 g) and three fertilizers types [cotton seed meal, 6N-0.9P-0.8K (0.18 kg.m-2), plus AZOMITE (1 kg.m-2); Nature Safe, 13N-0P-0K (0.07 kg.m-2); and Phytamin All Purpose Liquid fertilizer, 4N-1.3P-3.3K (0.26 L.m-2)] were used in 2018. In 2019 and 2020, three types of plant material and two fertilizer types at modified rates from the 2018 study, plus two storage containers (pans and flats), were tested. In general, the rhizome storage container did not affect plant height, leaf soil plant analysis development (SPAD) index, and rhizome yield, and its effect on tillers was none or mixed. Fertilizer type had mixed effects on plant height and tiller number, and no effect on the leaf SPAD index. Rhizome yields in 2019 and 2020 were unaffected by fertilizer, but Nature Safe produced a greater benefit-to-cost ratio (BCR) and profitability index (PI) than Phytamin. Soil P was generally less in Nature Safe-fertilized soil than in Phytamin-fertilized soil. Multishoot seedlings produced the greatest rhizome yield, BCR, PI, and tallest plants, and had some of the highest tiller numbers. These findings show that it would be more profitable to use multishoot seedlings as planting material in high tunnels compared with single-shoot seedlings and rhizome seeds. Furthermore, the lower P levels in the Nature Safe-fertilized soils compared with the Phytamin soils, and greater PI suggest that using Nature Safe will be a better choice than Phytamin for growing organic ginger. [ABSTRACT FROM AUTHOR]

The objective of this greenhouse study was to evaluate tall fescue (Festuca arundinacea) seedling growth when seeded after herbicide application. Herbicide treatments included a nontreated control; 1.19 lb/acre 2,4-dichlorophenoxyacetic acid (2,4-D) + 0.32 lb/acre methylchlorophenoxypropionic acid (MCPP) + 0.32 lb/acre dicamba; 0.75 lb/acre quinclorac; and 0.06 lb/acre halosulfuron-methyl. Seeding was done at 0, 3, 7, or 14 days after herbicide application to soil media. Two identical experiments were conducted in the greenhouse: Expt. 1 seedling growth from January to March and Expt. 2 from May to July (temperatures higher). Seeding dates after herbicide application did not influence growth. Average dry shoot weight reductions and dry root weight reductions caused by postemergence herbicides were 2,4-D + MCPP + dicamba (33% shoot and 27% root in Expt. 2), quinclorac (30% shoot and 37% root in Expt. 2), and halosulfuron-methyl (51% shoot in Expt. 2; 81% root in Expts. 1 and 2). Although application of these herbicides before seeding in the field may result in no visual impact, they can impact seedling shoot and root growth, particularly under higher growth temperatures.

Background and aimsIn peach (Prunus persica) trees, three types of shoots can be distinguished depending on the time of their appearance: sylleptic, proleptic and epicormic. On proleptic shoots, an average of ten phytomers are preformed in dormant buds prior to shoot growth after bud-break, whereas all phytomers are considered neoformed in sylleptic and epicormic shoots. However, casual observations indicated that proleptic and sylleptic shoots appear quite similar in number of phytomers and structure in spite of their different origins. The goal of this research was to test the hypothesis that both proleptic and sylleptic shoots exhibit similar growth characteristics by analysing their node numbers and bud fate patterns. If their growth characteristics are similar, it would indicate that the structure of both types of shoots is primarily under genetic rather than environmental control.MethodsThe number of phytomers and bud fate patterns of proleptic and sylleptic shoots of four peach cultivars grown in the same location (Winters, California) were analysed and characterized using hidden semi-Markov models. Field data were collected during winter 2016, just prior to floral bud-break.Key resultsSylleptic shoots tended to have slightly fewer phytomers than proleptic shoots of the same cultivars. The bud fate patterns along proleptic and sylleptic shoots were remarkably similar for all the cultivars, although proleptic shoots started growing earlier (at least 1 month) in the spring than sylleptic shoots.ConclusionsThis study provides strong evidence for the semi-deterministic nature of both proleptic and sylleptic shoots across four peach cultivars in terms of number of phytomers and bud fate patterns along shoots. It is apparent that the overall structure of shoots with similar numbers of phytomers was under similar genetic control for the two shoot types. Understanding shoot structural characteristics can aid in phenotypic characterization of vegetative growth of trees and in providing a foundation for vegetative management of fruit trees in horticultural settings.

【Objective】The large-scale cultivation of white sapote in China is in its initial stage, and the adaptability of white sapote in Guangdong is not clear yet. Clarifying the phenology of white sapote in Guangdong as well as its flowering and fruiting habits and summarizing cultivation techniques can provide guidance for the large-scale cultivation of white sapote.【Method】A white sapote cultivar 'W4' was used as the research material to observe its botanical characteristics, phenology, fruit growth law, fruit setting and fruit quality. The key points of its high-quality cultivation techniques were expounded from aspects of garden construction, fertilizer and water management, shaping and pruning, pest control and fruit harvesting.【Result】The flowering period of white sapote on was from late January to early February, and there were three growth peaks of shoot growth in April, June and September, respectively. The slow growth period was from November to next February. During fruit growth and development, there were three fruit-dropping peaks, which were in mid-March, mid-April and May to June before harvest. The average fruit weight is 148.93 g, and the shape index is 0.83. The fruit melts in the mouth like ice cream, the edible rate is 79.7%, the soluble solid content is 20.36%, and the solid acid ratio is 45.83. White sapote can withstand a low temperature of-2--4℃, which is higher than the average temperature of the coldest month(January) in Guangdong. Therefore, it can be cultivated in most areas of Guangdong.【Conclusion】This variety has good growth potential, strong adaptability, large single fruit quality, good flavor and excellent quality, and has high economic benefit in the market. It is a new fruit variety with planting potential. Attention should be paid to preventing anthracnose and sooty blotch in cultivation.White sapote is suitable for planting on the slope with loose soil and good drainage and irrigation in Guangdong. Dwarfing treatment should be done and tree shape be controlled for young trees.

Abstract Background Cotton production is adversely effected by drought stress. It is exposed to drought stress at various critical growth stages grown under a water scarcity environment. Roots are the sensors of plants; they detect osmotic stress under drought stress and play an important role in plant drought tolerance mechanisms. The seedling stage is very sensitive to drought stress, and it needed to explore the methods and plant characteristics that contribute to drought tolerance in cotton. Results Initially, seedlings of 18 genotypes from three Gossypium species: G. hirsutum, G. barbadense, and G. arboreum, were evaluated for various seedling traits under control (NS) and drought stress (DS). Afterward, six genotypes, including two of each species, one tolerant and one susceptible, were identified based on the cumulative drought sensitivity response index (CDSRI). Finally, growth rates (GR) were examined for shoot and root growth parameters under control and DS in experimental hydroponic conditions. A significant variation of drought stress responses was observed across tested genotypes and species. CDSRI allowed here to identify the drought-sensitive and drought-resistant cultivar of each investigated species. Association among root and shoots growth traits disclosed influential effects of enduring the growth under DS. The traits including root length, volume, and root number were the best indicators with significantly higher differential responses in the tolerant genotypes. These root growth traits, coupled with the accumulation of photosynthates and proline, were also the key indicators of the resistance to drought stress. Conclusion Tolerant genotypes have advanced growth rates and the capacity to cop with drought stress by encouraging characteristics, including root differential growth traits coupled with physiological traits such as chlorophyll and proline contents. Tolerant and elite genotypes of G. hirsutum were more tolerant of drought stress than obsolete genotypes of G. barbadense and G. arboreum. Identified genotypes have a strong genetic basis of drought tolerance, which can be used in cotton breeding programs.

The impact of some green pruning treatments on the shoot growth dynamics of Storgozia variety had been studied. The research was carried out in the Experimental Base of the Institute of Viticulture and Enology – Pleven during the period 2014-2020. The following green pruning treatments were applied – shoot topping in June and July, thinning of the clusters and lightening in the area around the clusters. All green pruning treatments had varying degree of influence on the vine growth strength. The shoot growth strength and dynamics and their changes were directly dependent on the weather conditions of the respective year, as an increase in their intensity in wet and warmer climatic conditions was recorded. The shoot length and the number of internodes formed on them were statistically proven to be less in the variants with shoot topping, compared to the control and all other experimental variants. [ABSTRACT FROM AUTHOR]

In plants, abscisic acid (ABA)-mediated responses during abiotic stress, growth, and development have been well studied. Many chemicals which modulate ABA responses have been identified. In this study, we report that dithiothreitol (DTT), an inducer of endoplasmic reticulum (ER) stress, can overcome ABA-mediated responses in plants. In rice seedlings, combined treatment of ABA and DTT increased shoot growth compared to ABA alone. The phenotype correlated with the expression pattern of ABA and ER stress-responsive genes. In finger millet, increase in root growth was observed in combined treatment, compared to ABA treatment. Experiments using dimethyl sulfoxide indicated that the phenotype observed was specific to DTT. Priming of germinated rice seeds with DTT followed by salinity stress indicated that DTT can mask the ABA effect. In ABA bioassay using cotton petioles, an increase in intact petioles in combined treatment of ABA and DTT was observed compared to ABA treatment. The expression of OsWRKY48, an ABA-responsive gene, was down-regulated in combined treatment, indicating that the target of DTT-induced ER stress is upstream of OsWRKY48 in the ABA signaling pathway. The study demonstrated that DTT-induced ER stress can be a potential mechanism to regulate ABA-mediated responses in plants. [ABSTRACT FROM AUTHOR]

We studied the allelopathic potential of above-ground vegetative shoots of 3-cultivars ('Ani', 'Bila', and 'Nandu') of Poa pratensis and their effects on the initial growth and development of 6-Acceptor plants spp (Agrostis capillaris cv. Niwa, Festuca arundinacea cv. Asterix, Festuca ovina cv. Espro, Festuca rubra cv. Areta, Lolium perenne cv. Stadion and P. pratensis cv. Bila) present in grass lawn community. Aqueous extracts from shoots of P. pratensis 3-cultivars were tested in Petri dishes on filter paper. Whereas, the dried chopped leaves of P. pratensis cultivars were incorporated in pots containing sand for assay. The phenolics and flavonoids in the plant materials were analyzed by liquid chromatography. The allelopathic potential of Donor P. pratensis cultivars on the acceptor plants were correlated with the leaf contents of flavonoids and phenolic acids and followed the Order: 'Ani' > 'Nandy' > 'Bila'. The allelopathic potential of Donor cultivars on the Acceptor plants in Petri dish Bioassays was higher than in Pot assays. Aqueous extracts were more inhibitory to root growth than to seed germination and shoot growth. In contrast, in Pot assay allelopathic substances released from the decomposing cut leaves were more inhibitory to sprouting seeds than shoot elongation. The A. capillaris was most sensitive to allelopathic effects of P. pratensis cultivars followed by F. rubra and P. pratensis. The plants of F. arundinacea and L. perenne were least sensitive. With this in mind, it is advised to remove the cut grass from the lawn surface. [ABSTRACT FROM AUTHOR]

While not classified as an essential plant nutrient, silicon (Si) assimilation following exogenous Si application has enhanced the wear resistance of cool-season turfgrass. Given this beneficial supplementation of lignin by Si reported in epidermal tissue of monocotyledonous plants, our research objective was to quantify root morphology, vegetative nutrition and vigor, soil chemistry, and putting green performance in response to split applications of pelletized liming agents rich in Si and/or Ca and Mg. Field evaluation of granular liming agent treatment, 2441 kg (ha year)−1, was conducted on creeping bentgrass (Agrostis stolonifera L. cv. Penn G-2) putting green maintained in the Mid-Atlantic US. Pelletized Ca/Mg-SiO3 slag or dolomitic limestone treatments were conducted in frequent split applications and incorporated into the upper 5 cm of the rootzone. Measurements of canopy color and density, shoot growth as clipping yield, soil pH, Si and nutrient content of clippings, and soil extractable Si were performed each season. Cumulative Ca/Mg-SiO3 application (kg ha−1) increased mean acetic acid (HOAc) extractable Si by 35 to 60 mg kg−1 and leaf Si content by 1.0 to 1.5 mg g−1. However, neither putting green canopy quality, shoot nutrient concentration, 5 to 15 cm depth root length density nor ball roll distance was improved by liming agent treatment. Liming agent-treated or untreated plots showed statistical, yet inconsistent, differences in clipping yield 4, 14, 15, 16, and 17 months from initiation (MFI). This thorough shuffling of treatment rank, resulting in identical experiment-wide means precludes the expectation of dependably superior vigor by any.

Purpose: Seed orientation is widely known to affect shoot growth, but the effects on root growth and crop drought tolerance are unclear. Thus, one germination paper experiment, two soil pot experiments and one field experiment were conducted to study the effects of seed orientation (Brush-up, Brush-down, Crease-up and Crease-down) on crop root and shoot growth under two water treatment levels (full and deficit) using winter wheat (Triticum aestivum L.) as an example. Methods: Seedling root traits, early shoot growth, mature root distribution, soil water consumption, root/shoot ratio, harvest index and grain yield were measured. Results: The results showed that under full irrigation, the control Brush-up orientation allowed for the highest grain production, mainly due to shoot growth. However, Crease-down resulted in the highest yield under limited-water supplies because root biomass was optimally related to grain yield in the pots, and a reasonably deep root system (lower root biomass and longer specific root length) benefitted yield production in the field. The higher shoot biomass, lower root/shoot ratio and higher harvest index also contributed to a higher grain yield under deficit irrigation, suggesting that sowing seeds lying flat with the crease down can optimize root and shoot growth and improve drought tolerance. Conclusions: To our knowledge, this is the first report verifying that seed orientation can significantly regulate root growth under dry conditions, providing a possible new mechanism underlying crop drought tolerance. [ABSTRACT FROM AUTHOR]

Composite trees combine optimal traits from both the rootstock and the scion. Dwarfing rootstocks are commonly used to reduce shoot vigour and improve fruit quality and productivity. Although growth habits of different rootstocks have been clearly described, the underlying physiological traits affecting scion vigour are not well understood. Plant water status and stem water potential are strongly influenced by water supply and demand through the soil–plant–atmosphere continuum. In the scion, stomata regulate water loss and are essential to prevent hydraulic failure. Stomatal conductance influences leaf carbon isotope composition. Combined, the effects of reduced stomatal conductance and, consequently, carbon fixation may affect tree growth. These differences could also correspond to differences in scion vigour controlled by rootstock genotype. Here, vegetative growth, gas exchange, stem water potential and leaf δ13C were compared to determine how rootstocks affect scion water relations and whether these differences correspond to shoot vigour. There was a range in vigour among rootstocks by almost 2-fold. Net leaf carbon assimilation rates were lower in rootstocks with lower vigour. Rootstock vigour was closely associated with leaf gas exchange and stem water potential in the scion and was reflected in leaf δ13C signatures. Dwarfing was strongly affected by changes to plant water status induced by rootstock genotype and these changes are distinguishable when measuring leaf and stem δ13C composition. These observations indicate that scion water relations and leaf carbon isotope discrimination were affected by rootstock genotype. These results have implications for better understanding dwarfing mechanisms in apple rootstocks and the relationship with water-use traits. [ABSTRACT FROM AUTHOR]

Background: Cotton production is adversely effected by drought stress. It is exposed to drought stress at various critical growth stages grown under a water scarcity environment. Roots are the sensors of plants; they detect osmotic stress under drought stress and play an important role in plant drought tolerance mechanisms. The seedling stage is very sensitive to drought stress, and it needed to explore the methods and plant characteristics that contribute to drought tolerance in cotton. Results: Initially, seedlings of 18 genotypes from three Gossypium species: G. hirsutum, G. barbadense, and G. arboreum, were evaluated for various seedling traits under control (NS) and drought stress (DS). Afterward, six genotypes, including two of each species, one tolerant and one susceptible, were identified based on the cumulative drought sensitivity response index (CDSRI). Finally, growth rates (GR) were examined for shoot and root growth parameters under control and DS in experimental hydroponic conditions. A significant variation of drought stress responses was observed across tested genotypes and species. CDSRI allowed here to identify the drought-sensitive and drought-resistant cultivar of each investigated species. Association among root and shoots growth traits disclosed influential effects of enduring the growth under DS. The traits including root length, volume, and root number were the best indicators with significantly higher differential responses in the tolerant genotypes. These root growth traits, coupled with the accumulation of photosynthates and proline, were also the key indicators of the resistance to drought stress. Conclusion: Tolerant genotypes have advanced growth rates and the capacity to cop with drought stress by encouraging characteristics, including root differential growth traits coupled with physiological traits such as chlorophyll and proline contents. Tolerant and elite genotypes of G. hirsutum were more tolerant of drought stress than obsolete genotypes of G. barbadense and G. arboreum. Identified genotypes have a strong genetic basis of drought tolerance, which can be used in cotton breeding programs. [ABSTRACT FROM AUTHOR]

Abstract Transcription factors (TFs) such as ethylene-responsive factors (ERFs) are important for regulating plant growth, development, and responses to abiotic stress. Notably, more than half of the rice ERF-X group members, including ethylene-responsive factor 106 (OsERF106), are abiotic stress-responsive genes. However, their regulatory roles in abiotic stress responses remain poorly understood. OsERF106, a salinity-induced gene of unknown function, is annotated differently in RAP-DB and MSU RGAP. In this study, we isolated a novel (i.e., previously unannotated) OsERF106 gene, designated OsERF106MZ (GenBank accession No. MZ561461), and investigated its role in regulating growth and the response to salinity stress in rice. OsERF106MZ is expressed in germinating seeds, primary roots, and developing flowers. Overexpression of OsERF106MZ led to retardation of growth, relatively high levels of both malondialdehyde (MDA) and reactive oxygen species (ROS), reduced catalase (CAT) activity, and overaccumulation of both sodium (Na+) and potassium (K+) ions in transgenic rice shoots. Additionally, the expression of OsHKT1.3 was downregulated in the shoots of transgenic seedlings grown under both normal and NaCl-treated conditions, while the expression of OsAKT1 was upregulated in the same tissues grown under NaCl-treated conditions. Further microarray and qPCR analyses indicated that the expression of several abiotic stress-responsive genes such as OsABI5 and OsSRO1c was also altered in the shoots of transgenic rice grown under either normal or NaCl-treated conditions. The novel transcription factor OsERF106MZ negatively regulates shoot growth and salinity tolerance in rice through the disruption of ion homeostasis and modulation of stress-responsive gene expression.

Mutual leaf shading can inhibit the growth of yam, reducing tuber yield. To improve light utilization, approximately 25% of leaves in a plant were thinned during the period of maximum shoot growth. Shoot dry weight was estimated every two weeks using a non-destructive method. Leaf thinning caused higher shoot growth rates (SGRs) after thinning, while control plants had SGRs close to zero. The higher SGRs in the thinned plants was attributed to an increase in new leaf development. This indicates that the plateau in shoot growth commonly observed during the late growth period is reversible and could be improved artificially. In thinned plants, there was a positive relationship between shoot dry weight and SGR, although no such relationship was observed in control plants after the middle growth period. This positive correlation indicates a higher shoot growth per unit leaf area in the thinned plants than in the control plants, presumably due to improved light utilization and a higher photosynthetic rate of new leaves. However, leaf thinning reduced tuber yields, presumably because of a lower total carbon assimilation per plant and greater growth competition between shoots and tubers. High correlations between shoot dry weight and tuber yield indicated that a high shoot biomass is more important than improving light utilization for increased tuber yields.

Dodder (Cuscuta spp.) species are obligate parasitic flowering plants that totally depend on host plants for growth and reproduction and severely suppress hosts' growth. As a rootless and leafless plant, excised dodder shoots exhibit rapid growth and elongation for several days to hunt for new host stems, and parasitization could be reestablished. This is one unique ability of the dodder to facilitate its success in nature. Clearly, excised dodder stems have to recycle stored nutrients to elongate as much as possible. However, the mechanism of stored nutrient recycling in the in vitro dodder shoots is still poorly understood. Here, we found that dodder is a carbohydrate-rich holoparasitic plant. During the in vitro dodder shoot development, starch was dramatically and thoroughly degraded in the dodder shoots. Sucrose derived from starch degradation in the basal stems was transported to the shoot tips, in which EMP and TCA pathways were activated to compensate for carbon demand for the following elongation according to the variations of sugar content related to the crucial gene expression, and the metabolomics analysis. Additionally, antioxidants were significantly accumulated in the shoot tips in contrast to those in the basal stems. The variations of phytohormones (jasmonic acid, indole-3-acetic acid, and abscisic acid) indicated that they played essential roles in this process. All these data suggested that starch and sucrose degradation, EMP and TCA activation, antioxidants, and phytohormones were crucial and associated with the in vitro dodder shoot elongation. [ABSTRACT FROM AUTHOR]

Temperature is a critical environmental factor regulating plant growth and yield. Corn is a major agronomic crop produced globally over a vast geographic region, and highly variable climatic conditions occur spatially and temporally throughout these regions. Current literature lacks a comprehensive study comparing the effects of temperature on above versus below-ground growth and development and biomass partitioning of corn measured over time. An experiment was conducted to quantify the impact of temperature on corn's early vegetative growth and development. Cardinal temperatures (Tmin, Topt, and Tmax) were estimated for different aspects of above- and below-ground growth processes. Plants were subjected to five differing day/night temperature treatments of 20/12, 25/17, 30/22, 35/27, and 40/32 °C using sun-lit controlled environment growth chambers for four weeks post-emergence. Corn plant height, leaves, leaf area, root length, surface area, volume, numbers of tips and forks, and plant component part dry weights were measured weekly. Cardinal temperatures were estimated, and the relationships between parameters and temperature within these cardinal limits were estimated using a modified beta function model. Cardinal temperature limits for whole plant dry weight production were 13.5 °C (Tmin), 30.5 °C (Topt), and 38 °C (Tmax). Biomass resources were prioritized to the root system at low temperatures and leaves at high temperatures. Root growth displayed the lowest optimum temperature compared to root development, shoot growth, and shoot development. The estimated cardinal temperatures and functional algorithms produced in this study, which include both above and below-ground aspects of plant growth, could be helpful to update crop models and could be beneficial to estimate corn growth under varying temperature conditions. These results could also be applicable when considering management decisions for maximizing field production and implementing emerging precision agriculture technology. [ABSTRACT FROM AUTHOR]

Dodder (Cuscuta spp.) species are obligate parasitic flowering plants that totally depend on host plants for growth and reproduction and severely suppress hosts’ growth. As a rootless and leafless plant, excised dodder shoots exhibit rapid growth and elongation for several days to hunt for new host stems, and parasitization could be reestablished. This is one unique ability of the dodder to facilitate its success in nature. Clearly, excised dodder stems have to recycle stored nutrients to elongate as much as possible. However, the mechanism of stored nutrient recycling in the in vitro dodder shoots is still poorly understood. Here, we found that dodder is a carbohydrate-rich holoparasitic plant. During the in vitro dodder shoot development, starch was dramatically and thoroughly degraded in the dodder shoots. Sucrose derived from starch degradation in the basal stems was transported to the shoot tips, in which EMP and TCA pathways were activated to compensate for carbon demand for the following elongation according to the variations of sugar content related to the crucial gene expression, and the metabolomics analysis. Additionally, antioxidants were significantly accumulated in the shoot tips in contrast to those in the basal stems. The variations of phytohormones (jasmonic acid, indole-3-acetic acid, and abscisic acid) indicated that they played essential roles in this process. All these data suggested that starch and sucrose degradation, EMP and TCA activation, antioxidants, and phytohormones were crucial and associated with the in vitro dodder shoot elongation.

In many arid and semi-arid regions, increasing water scarcity pushes woody species to their physiological limits, making strong drought resistance essential for adaptive forest management. Here, we examined morpho-physiological and biochemical drought responses of the forestry-relevant Persian oak (Quercus brantii Lindl.) and black poplar (Populus nigra L.). In a 120-day greenhouse pot experiment, seedlings were subjected to three watering regimes (FC100, FC60, and FC30, indicating percentages of field capacity). Under FC100 conditions, all biomass measures and the total and specific leaf area of oak were significantly greater compared to those of poplar. FC60-exposed poplar seedlings exhibited strong declines in relative water content (RWC; −33%) and carotenoids (−46%) and a surge in electrolyte leakage (EL; +51%), while these parameters did not change significantly in oak. Although both species showed 80% EL under FC30 conditions, poplar suffered more severe drought damage than oak as evidenced by a 65% lower survival, stronger reductions in RWC and total chlorophyll, as well as stronger increases in oxidative stress markers. Accordingly, poplar seedlings displayed a drought-related 56% decline in quality index while only statistically insignificant reductions occurred in oak seedlings. The superior drought resistance of oak seedlings implies economically more viable nursery production and better seedling establishment, suggesting a shift towards Persian oak-dominated forestry in its natural range under future climate projections. [ABSTRACT FROM AUTHOR]

The response of plant cultivars to infestation by single aphid species has been widely reported, whereas the response of plants to multiple aphid species, and the mechanisms by which various aphids benefit from the induced changes, has been largely ignored. Here we analyzed the symptoms and physiological responses of sweet orange, Citrus sinensis (L.) Osbeck (Rutaceae), as affected by Aphis spiraecola Patch and Aphis (Toxoptera) citricidus (Kirkaldy) (Hemiptera: Aphididae). We further compared the feeding behavior, population abundance, and proportion of winged morph of the two aphid species when separately feeding on sweet orange. Results showed that feeding by A. spiraecola, but not A. citricidus, caused leaf curling, reduced shoot length, shoot fresh weight, and chlorophyll concentration. In addition, A. spiraecola feeding increased the concentration of essential amino acids in leaves when compared with A. citricidus and uninfested control plants. Electrical penetration graph‐studies showed that A. citricidus gained faster access and acceptance of phloem, and spent more time ingesting phloem sap, than A. spiraecola. Furthermore, after 2 weeks of infestation, A. spiraecola produced more winged morphs, whereas A. citricidus achieved higher population abundance. Thus, our results indicate that the two citrus aphids utilize divergent strategies to manipulate host metabolism, and gain fitness benefits in population abundance or winged form production. The results could improve our understanding of varied adaptive strategies of co‐existing insects and extend our knowledge of aphid‐plant interactions. [ABSTRACT FROM AUTHOR]

Mutual leaf shading can inhibit the growth of yam, reducing tuber yield. To improve light utilization, approximately 25% of leaves in a plant were thinned during the period of maximum shoot growth. Shoot dry weight was estimated every two weeks using a non-destructive method. Leaf thinning caused higher shoot growth rates (SGRs) after thinning, while control plants had SGRs close to zero. The higher SGRs in the thinned plants was attributed to an increase in new leaf development. This indicates that the plateau in shoot growth commonly observed during the late growth period is reversible and could be improved artificially. In thinned plants, there was a positive relationship between shoot dry weight and SGR, although no such relationship was observed in control plants after the middle growth period. This positive correlation indicates a higher shoot growth per unit leaf area in the thinned plants than in the control plants, presumably due to improved light utilization and a higher photosynthetic rate of new leaves. However, leaf thinning reduced tuber yields, presumably because of a lower total carbon assimilation per plant and greater growth competition between shoots and tubers. High correlations between shoot dry weight and tuber yield indicated that a high shoot biomass is more important than improving light utilization for increased tuber yields. [ABSTRACT FROM AUTHOR]

SUMMARY: Drought stress constitutes one of the major constraints to agriculture all over the world, and its devastating effect is only expected to increase in the following years due to climate change. Concurrently, the increasing food demand in a steadily growing population requires a proportional increase in yield and crop production. In the past, research aimed to increase plant resilience to severe drought stress. However, this often resulted in stunted growth and reduced yield under favorable conditions or moderate drought. Nowadays, drought tolerance research aims to maintain plant growth and yield under drought conditions. Overall, recently deployed strategies to engineer drought tolerance in the lab can be classified into a 'growth‐centered' strategy, which focuses on keeping growth unaffected by the drought stress, and a 'drought resilience without growth penalty' strategy, in which the main aim is still to boost drought resilience, while limiting the side effects on plant growth. In this review, we put the scope on these two strategies and some molecular players that were successfully engineered to generate drought‐tolerant plants: abscisic acid, brassinosteroids, cytokinins, ethylene, ROS scavenging genes, strigolactones, and aquaporins. We discuss how these pathways participate in growth and stress response regulation under drought. Finally, we present an overview of the current insights and future perspectives in the development of new strategies to improve drought tolerance in the field. Significance Statement: In this review, several molecular pathways that participate in plant growth regulation under drought stress are discussed. An overview of successful strategies and potential candidates to enhance plant growth under drought is presented. [ABSTRACT FROM AUTHOR]

Salinity stress is among the major abiotic stresses prevailing in arid and semiarid areas such as the southern high plains of the United States. In these areas, both declining quality of groundwater and cultivation practices have resulted in increased accumulation of salts in the root zone. The occurrence of excessive salts in the root zone is detrimental for plant growth and economic yield. Recently, biochar has received a great consideration as a soil amendment to mitigate the detrimental impacts of salinity stress. However, the effectiveness of biochar to mitigate the salinity stress depends on the feedstock type, pyrolysis temperature and time, soil type and properties, and plant species. Therefore, a pot experiment in a greenhouse was conducted to 1) examine the effects of salinity stress on physiology, shoot and root growth, and yield of eggplant (Solanum melongena L.), and 2) evaluate the potential of hardwood biochar and softwood biochar to mitigate the damaging effects of salinity stress on eggplant. The experiment was conducted in a split-plot design with three salinity levels of irrigation water [S0 (control, 0.04 dS·m−1), S1 (2 dS·m−1), and S2 (4 dS·m−1)] as main-plot factor and three biochar treatments [B0 (control, non-biochar), Bh (hardwood biochar), and Bs (softwood biochar)] as subplot factor with four replications. Results showed that stomatal conductance (gS) and photosynthesis rate decreased significantly, while leaf temperature and electrolyte leakage increased significantly with increase in irrigation water salinity levels. Root growth (root length density and root surface area density), shoot growth (plant height, stem diameter, and leaf area), and yield of eggplant declined with increase in levels of salinity stress. Biochar application helped to enhance gS and photosynthesis rate, and to decrease leaf temperature and electrolyte leakage in leaf tissues of plants. This resulted in better root growth, shoot growth, and fruit yield of eggplant in treatments amended with biochar than non-biochar (control) treatment. There was no significant difference in the effect of two types of biochars (hardwood and softwood biochar) on physiology, root growth, shoot growth, and yield of eggplant. Therefore, it can be concluded that softwood and hardwood biochars could be used to minimize the detrimental impacts of salinity stress in eggplant.

Abstract Background The environmental control of flowering in apple (Malus × domestica Borkh.) has remained an enigma for generations. Methods We studied growth and flowering effects of temperature under daylight phytotron conditions in 3-year old ‘Summerred’ and ‘Discovery’ apple trees. Flowering was assessed by dissection of buds on spurs and extension shoots at termination of treatments and flowering performance in the subsequent spring. Results Exposure to constant temperatures ranging from 12 to 27 °C for 12 weeks yielded a hyperbolic response curve with optimum at 18–21 °C and little or no flowering at 12 and 27 °C. A drop from high to low temperature after 6 weeks caused growth cessation and initiation of flowering, whereas the reverse shift had the opposite effect. Shoot growth and leaf accumulation increased with increasing temperature, but under flower-inducing conditions, both levelled off and ceased towards the end of the treatment period. Conclusions The results are discussed in relation to the extensive physiological and genetic literature on the subject. We interpret the results as two separate effects of temperature on flowering in apple. At 12 °C flowering seems to be limited by low temperature depression of growth and leaf production, while at 27 °C, flowering is blocked by inhibition of the floral initiation itself. Intermediate temperatures of 18–21 °C, on the other hand, seem to satisfy the requirements for both processes. These opposite effects of temperature have apparently confounded the understanding of the environmental control of flowering in apple.

Approximately 30% of harvested yams are used in subsequent plantings as seed tubers, which reduces the harvest size; however, planting tuber pieces (setts) potentially represents a viable alternative. To determine how sett size affects yam production, different sett sizes were compared for sprouting, shoot growth, and tuber yield. Larger setts exhibited faster sprouting with greater shoot biomass due to larger shoot growth rates during the early growth period. Tuber yield from 200 g setts was higher than that from 50 g setts; however, this yield advantage was not enough to compensate for the cost of larger sett size. Thus, planting 50 g setts might be the most cost-effective. Even the 50 g setts yielded higher than 1 kg tuber per plant which were available for selling in markets. Thus, planting with smaller setts can be promising method for efficiently improving yam production.

Growth regulation of apple trees is an important measurement to guarantee a constant yield and good fruit quality. In two different trials at Laimburg Research Centre, few methods of growth regulation were evaluated. With the commercial product Paclot New, the active agent paclobutrazol - well known in the past as the commercial product Cultar - was also evaluated. Despite positive results in the past with paclobutrazol, in these two trials no effect of growth inhibition was observed. Only the treatments with prohexadione-Ca could reduce the shoot growth significantly in comparison with the untreated control. Moreover, the root pruning and treatments with paclobutrazol reduced the fruit size significantly in some years. No residues of paclobutrazol were detected during the trials; only in the leaf and shoots and one single year in the soil residues were found.

1. Despite worldwide reports of high tree mortality, growing evidence indicates that many tree species are well adapted to survive repeated dry spells. The drought resilience of trees is related to their phenotypic plasticity and ecotypic differentiation. Whether these two mechanisms act at the same organisational level of a tree and involve similar plant traits is still unknown. 2. We assessed phenotypic plasticity and ecotypic differentiation across four populations of Pinus sylvestris and Pinus nigra seedlings grown for 3 years under a recurrent summer drought treatment or well-watered control conditions in a common garden. We measured the response to the summer drought treatment of a total of 26 traits including shoot and needle morphology, needle anatomy and foliar macronutrients, and related the traits to the growing season water deficit (GSWD) at the location of the seed origin. 3. Foliar phenotypic plasticity in response to recurrent summer drought was surprisingly low, with the needle length and the fraction of mesophyll and phloem tissue adjusting to some extent. In comparison, shoot morphological traits were much more plastic in both species with predominant responses to the summer drought stress including shorter and less numerous apical and lateral shoots. These three traits were also correlated with GSWD at the seed origin, indicating local adaptation. In contrast, between-population variation of foliar morphological and anatomical traits, and macronutrients were mostly unrelated to the GSWD at the seed origin. 4. Consequently, phenotypic plasticity and ecotypic differentiation occurred at the same level of organisation and in the same plant traits, that is, shoot morphology. This combination of plasticity and ecotypic differentiation allowed P. sylvestris and P. nigra seedlings to rapidly acclimate to recurrent and long-lasting dry spells. 5. Synthesis. Pinus sylvestris and P. nigra seedlings showed considerable ecotypic differentiation and phenotypic plasticity of shoot morphological traits, and not foliar traits. Acclimation to recurrent severe summer drought was achieved by reducing shoot growth. [ABSTRACT FROM AUTHOR]