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The escalation in the intensity, frequency, and duration of high-temperature (HT) stress is currently unparalleled, which aggravates the challenges for crop production. Yet, the stage-dependent responses of reproductive organs to HT stress at the morphological, physiological, and molecular levels remain inadequately explored in pivotal staple crops. This review synthesized current knowledge regarding the mechanisms by which HT stress induces abnormalities and aberrations in reproductive growth and development, as well as by which it alters the morphology and function of florets, flowering patterns, and the processes of pollination and fertilization in maize (Zea mays L.). We identified the stage-specific sensitivities to HT stress and accurately defined the sensitive period from a time scale of days to hours. The microspore tetrad phase of pollen development and anthesis (especially shortly after pollination) are most sensitive to HT stress, and even brief temperature spikes during these stages can lead to significant kernel loss. The impetuses behind the heat-induced impairments in seed set are closely related to carbon, reactive oxygen species, phytohormone signals, ion (e.g. Ca2+) homeostasis, plasma membrane structure and function, and others. Recent advances in understanding the genetic mechanisms underlying HT stress responses during maize sexual reproduction have been systematically summarized. [ABSTRACT FROM AUTHOR]

The impact of water deficit severity and the specific growth stages at which water stress is applied have been found to have significant implications for both tomato yield and fruit quality. Recent findings have highlighted the influence of water deficits during the reproductive phase on tomato fruit quality. This study aimed to assess the effects of deficit irrigation on tomato fruit quality and overall plant productivity. Cherry tomatoes (Solanum lycopersicum var. cerasiforme) were grown in a greenhouse from August to November 2022. Three distinct watering regimes were implemented: Daily watering (T1), watering every 3 days (T2) and watering every 7 days (T3), starting from the flowering stage and continuing through subsequent plant development stages. The mean soil metric potentials (SMP) were -4.9, -29.7 and -52.8 kPa for T1, T2 and T3, respectively. Various traits of fruit size, fruit biomass, total soluble solids (TSS), water content, glucose content and lycopene content were measured. Additionally, the overall plant biomass and root-to-shoot ratio were evaluated. The results revealed that traits of the fruit size, such as diameter, length, volume and fresh weight, were most favorable when plants were subjected to the T2 watering regime, while higher and lower watering frequencies led to smaller fruit sizes. Interestingly, the TSS concentration had the most pronounced response to drought stress, indicating increased fruit sweetness. However, the fruit water content, glucose content and lycopene content remained unaffected by the different watering regimes. Furthermore, plants subjected to the T3 with the minimum SMP at -196.4 kPa exhibited enhanced development of the root system, prioritizing resource acquisition such as water and mineral nutrients over shoot components. In conclusion, this study provided valuable insights for agricultural practitioners, offering a range of alternatives that can inform optimal irrigation strategies that effectively enhance the quality of cherry tomato yields. [ABSTRACT FROM AUTHOR]

Flowering regulation is a reflection of plant self-adaptation to the environment and is the main determinant of plant yield. The quantitative trait loci (QTL) mapping of agronomic traits associated with the flowering stage of Agropyron Gaertn. was conducted using a cross-pollinated (CP) hybrid population with a total of 113 plant lines between A. mongolicum Keng Z2098 and A. cristatum (L.) Gaertn. Z1842 under four different environmental conditions and the genetic map constructed of 1,023 single-nucleotide polymorphism (SNP) markers. The results showed that 28 QTLs were detected on seven linkage groups. Each QTL explained 0.39–18.46% of the phenotypic variation, with a logarithm of odds (LOD) value ranging from 2.52 to 30.51. Specifically, QTLs were identified for various characteristics: one QTL identified for tiller number (TN), two for plant height (PH), three for days-to-flowering (DTF), five for flag leaf length (FLL), three for flag leaf width (FLW), three for spike length (SL), eight for spike width (SW), one for spikelet number per spike (SNS), and two for flower number per spike (FNS). One stable QTL controlling the SW was detected in two environments at the same loci and was located at 26 cM (Marker29867–Marker26864) on chromosome 5, showing a positive genetic effect. The two QTL enrichment regions suggested that the QTLs might contribute to trait correlation or pleiotropic genes. The identified QTLs potentially offer utility for marker-assisted breeding selection. [ABSTRACT FROM AUTHOR]

High temperature around flowering has a serious impact on the growth and development of maize. However, few maize genes related to flowering under heat stress have been confirmed, and the regulatory mechanism is unclear. To reveal the molecular mechanism of heat tolerance in maize, two maize hybrids, ZD309 and XY335, with different heat resistance, were selected to perform transcriptome and metabolomics analysis at the flowering stage under heat stress. In ZD309, 314 up-regulated and 463 down-regulated differentially expressed genes (DEGs) were detected, while 168 up-regulated and 119 down-regulated DEGs were identified in XY335. By comparing the differential gene expression patterns of ZD309 and XY335, we found the "frontloaded" genes which were less up-regulated in heat-tolerant maize during high temperature stress. They included heat tolerance genes, which may react faster at the protein level to provide resilience to instantaneous heat stress. A total of 1062 metabolites were identified via metabolomics analysis. Lipids, saccharides, and flavonoids were found to be differentially expressed under heat stress, indicating these metabolites' response to high temperature. Our study will contribute to the identification of heat tolerance genes in maize, therefore contributing to the breeding of heat-tolerant maize varieties. [ABSTRACT FROM AUTHOR]

Context. As global temperatures increase, heat waves of >30°C for at least 3 days are projected to become more frequent during reproductive development of wheat, causing reductions in grain yield. Breeding for tolerance is difficult under field conditions owing to the unpredictable timing and intensity of natural heat events and the narrow developmental windows of sensitivity. Aims. We report on a series of experiments designed to explore genetic variability for floret sterility induced by natural heat waves in the field by targeting a sensitive development stage. Methods. Our method involved sowing late, and the use of auricle distance to identify main tillers exposed to heat events at a sensitive developmental stage (booting). Key results. Substantial genetic variation was found for tolerance of grain set to natural heat waves, with a broad-sense heritability estimate of 0.94 for heat-exposed stems compared with 0.72 for non-stressed controls. An auricle distance of 1-3 cm was established as a phenotypic marker for tagging stems at the sensitive stage of development, and the optimal number of spikes to assess was determined as 10-15 per plot. A validation study with durum lines previously classified as tolerant/intolerant under glasshouse conditions showed agreement in ranking of genotypes at the extremes of tolerance. Conclusions. We demonstrate that it is possible to screen wheat genotypes for stage-specific tolerance to natural heat waves in the field. Implications. The protocol described could provide a low-cost method for evaluating heat tolerance in wheat, with relevance to commercial field production conditions. The approach allows tolerance to be assessed at a single stage of reproductive development, which should allow greater heritability in field assessments. [ABSTRACT FROM AUTHOR]

Introduction: Legumes are the second most important food source in the world after cereals. Beans are very effective in stabilizing nitrogen and fertility of agricultural soil due to their coexistence with bacteria, and large amounts of nitrogen are added to the soil every year after harvesting this plant. Environmental factors, especially drought stress conditions, play a major role in the quantitative and qualitative characteristics of crops. Reduction of available water, especially at the beginning of the flowering stage and the occurrence of drought stress in legumes, while reducing the rate of vegetative growth and shortening the stage of reproductive growth has a negative effect on grain quality. Nutritional deficiencies in plants cause them to be sensitive to environmental stresses. Excessive use of chemical fertilizers in agriculture to provide the phosphate needed by plants has always caused adverse environmental effects and has led to a decline in the quality of agricultural products. However, the use of biofertilizers has many benefits over chemical fertilizers. Therefore, considering the importance of the above, the purpose of this study is to investigate the role of biofertilizer and phosphorus fertilizer on bean plant elements in drought stress conditions. Materials and Methods: An experimental split-split plot with three replications was performed to investigate the effect of bio-fertilizer and phosphate fertilizer application on nutrient uptake in roots, stems, and seeds of beans under drought stress in season 2016-2017 in Ilam city. Treatments included three levels of irrigation interruption (non-stress conditions, cut off in flowering stage, and cut off in pod formation stage) in the main plot and three levels of phosphate fertilizer (25, 50, and 100 kg. ha1) and application and non-application of biofertilizer. Drought stress treatment in this experiment was performed by stopping irrigation in two stages of full flowering and podding. All phosphorus fertilizer related to each treatment was applied to the ground at once during cultivation. After germination and establishment of the plants in the 2-4 leaf stage, the plants were thinned and one plant was kept in each pile. Weed control was done manually in two stages before flowering. Results and Discussion: The results showed that the highest nitrogen concentrations in roots, stems, and seeds under non-stress conditions (full irrigation) were 1.12, 1.77, and 3.19%, respectively. Also, the lowest nitrogen concentrations of roots, stems, and seeds in the cut-off flowering stage were 0.92, 1.46, and 2.63%, respectively. The mean comparison results showed that the highest grain nitrogen concentration in non-stress conditions (full irrigation) was 3.19%, which increased by 21.29% compared to the cut-off irrigation treatment at the flowering stage. The results showed that the highest concentration of root potassium in the conditions of irrigation interruption in the flowering stage and biofertilizer application was 2.63% and the lowest was obtained in the treatment without stress and non-application of biofertilizer (2%). The average comparison results showed that the highest concentration of potassium in the stem was obtained in the condition of cut off irrigation in the flowering stage at the rate of 4.35% and the lowest amount was obtained in the full irrigation at the rate of 3.60%. The results showed that in the treatment of biofertilizer application, the highest concentration of phosphorus in the grain was 0.265 percent, while the lowest in the treatment of nonapplication of biofertilizer was 0.226 percent. Conclusion:The application of phosphate fertilizer significantly increased the absorption of elements. The application of biofertilizer also significantly increased the concentration of nitrogen, potassium, and phosphorus in bean plants. In general, the results of this study showed that the use of biofertilizer and phosphate fertilizer could reduce the adverse effects of drought stress on bean plants and increase the absorption of elements in bean organs. [ABSTRACT FROM AUTHOR]

In order to find out the freezing injury index of Camellia oleifera, a Camellia variety named “Tiecheng No. 1”was used as test material, a artificial control experiment was carried out at the Camellia oleifera base in Changde city, Hunan province in 2020 and 2021, respectively. Taking the natural state as a control, several low-temperature freezers were used to set low-temperature treatments with different intensities at −6℃ to 3℃(or −8℃ to 2℃) for 4 hours, and the Camellia oleifera branches at the flowering stage were placed in the freezers in a non-isolated way. 7 days after treatment, the morphological changes of Camellia oleifera were observed, and the rate of falling flower (fruit) and photosynthetic parameters were determined. The results showed that the morphological indicators of Camellia oleifera, falling flowers (fruit) rate and the light response parameters were clearly changed by low temperature. As the temperature decreased, the symptoms of freezing injury became more obvious, falling flowers (fruit) rate increased, while the maximum net photosynthetic rate, apparent quantum efficiency and saturation irradiation decreased. According to the symptoms of freezing damage and the response of the above physiological indicators to different low temperatures, it was determined that −2℃ was the upper limit of freezing damage of Camellia oleifera during flowering period, −6℃ was the critical temperature for significant aggravation of freezing damage, and −8℃ was the critical temperature for serious freezing damage. It was concluded that the slight freezing injury index of Camellia oleifera during flowering period was: −6℃＜daily minimum temperature ≤−2℃, and the moderate freezing injury index was:−8℃＜daily minimum temperature≤−6 ℃, and the severe freezing damage was: daily minimum temperature ≤−8℃. [ABSTRACT FROM AUTHOR]

High temperatures during flowering stage affects the seed setting in maize and thereby result in significant yield penalties in recent changing climate era. Based on the daily maximum temperature data of the maize growing season from 1971 to 2019 at the surface meteorological observatory in Henan Province of China and maize observation data at the agricultural meteorological observatory, an early warning grade of high temperatures during the summer maize flowering stage was constructed. The daily maximum temperature of the summer maize flowering stage was ≥ 32 °C as the critical threshold of high temperature disaster, and ≥ 35 °C as the threshold of high temperature disaster. The number of high temperature days (HD) ≥ 32 °C and ≥ 35 °C during 10 days of the summer maize flowering stage were counted. The sequence of high temperature days of summer maize flowering stage was constructed and its normal distribution characteristics were verified. The quartile value of the normal distribution sequence was selected as the threshold value of high temperature in different grades, and the high temperature heat damage in the summer maize flowering stage was divided into three early warning meteorological grades. The index verification of the early warning meteorological grade was carried out by using the observation data of kernel number per ear in the agricultural meteorological station for maize. The results showed that the three grade indexes corresponding to the number of high temperature days with daily maximum temperature ≥ 32 °C were: 3 ≤ HD < 5 (Grade I), 5 ≤ HD < 7 (Grade II), and HD ≥ 7 (Grade III) and the three grade indexes corresponding to high temperature days ≥ 35 °C were: 2 ≤ HD < 3 (Grade I), 3 ≤ HD < 5 (Grade II), HD ≥ 5 (Grade III). The constructed indexes were verified as follows, the number of high temperature days ≥ 32 °C at about 90% stations was significantly negatively correlated with the number of maize grains per ear, and 74% stations which the number of high temperature days ≥ 35 °C was significantly negatively correlated with the number of maize grains per ear. Applying this index to evaluate the high temperature risk in the flowering period, we can indicate that the high temperature risk had trend of increasing gradually from north to south. In conclusion, the constructed high temperature warning meteorological grade index during the flowering stage could accurately reflect the damage grade of maize during the flowering stage. [ABSTRACT FROM AUTHOR]

Sesame (Sesamum indicum L.) is a tropical oilseed crop that is also cultivated in arid and semi-arid environments, where drought occurs frequently. The objective of this study was to assess the performance of some sesame mutants, developed by our team through EMS-mutagenesis in 2020, under well-watered conditions and restricted irrigation by analyzing certain morphological, physiological, and agronomic attributes. The experiment was conducted in pots under field conditions according to a completely randomized design with three replications. The stress was simulated by suspending and reducing irrigation to 50% of the control, from the beginning of flowering until the appearance of the first capsule. The results showed variation attributable to genotypes, water regimes and their interaction was significant for all parameters studied, except the number of seeds per capsule. The mutants "ML2-5", "ML2-72" and "ML2-37" were found to be the most tolerant to drought, exhibiting lowest stress sensitivity index and highest seed yield were associated with higher proline content in the leaves, more developed root system, higher chlorophyll content, and higher stomatal conductance than the rest of the mutants studied. This is the first report of sesame mutant lines with such high tolerance to drought during flowering. They could be used for developing high-performing cultivars with tolerance to drought during the flowering stage. The number of capsules per plant and stomatal conductance can be considered selection criteria to improve water-stress tolerance in sesame. [ABSTRACT FROM AUTHOR]

Drought is a major crop production constraint worldwide. Some legume crops are known for their ability to resist water deficit stress. This study evaluated the responses of bambara groundnut (Vigna subterranea (L.) Verdc) and groundnut (Arachis hypogaea (L.) to soil water deficit stress. The experiment was set as a split-plot randomized complete block design. Three bambara groundnut landraces: viz DodR, NALBAM 4 and S19-3, and one groundnut variety, MNANJE, were assigned to subplots with three water regimes assigned to main plots (regime one: irrigated throughout the growing period, regime two: water deficit stress was imposed at the start of flowering to the end of first flush flowering, regime three: water was withheld during the pod development). Water deficit stress increased proline content by 123% in stressed plots. The highest (174%) and lowest (89%) proline increases were evident in the genotypes MNANJE and NALBAM 4, respectively. Water deficit decreased stomatal conductance, transpiration rate and photosynthetic rate, with MNANJE and S19-3 showing the smallest percentage decrease in most of the traits. This suggests that the two genotypes are drought resistant. The variations observed among landraces could be exploited to breed resilient varieties for cultivation in drought-prone areas, ultimately improving food security. [ABSTRACT FROM AUTHOR]

Aphid is one of the main insect pests of wheat in the flowering stage, so timely and effective control of wheat aphids plays an important role in ensuring wheat yield. The crop protection Unmanned Aerial Vehicle (UAV) is widely used in the control of wheat pests and diseases nowadays. In order to screen out the suitable operation parameters of the crop protection UAV to control the wheat aphids, this study conducted wheat aphid distribution investigation tests and droplet distribution tests. With the P20 electric four-rotor crop protection UAV (Guangzhou Jifei Technology Co., Ltd., Guangzhou, China) as the test equipment, four levels of flight speed (FS: 3, 4, 5, 6 m/s) and three levels of flight height (FH: 1.5, 2, 2.5 m) were combined as operation parameters, tests were carried out to compare the density and uniformity of droplet coverage, and the wheat aphid control tests were carried out by using the optimized operation parameters. The results of the wheat aphid distribution investigation test showed that aphids mainly distributed in the lower layer of the wheat plant canopy, accounting for more than 90.61%. The results of the droplet distribution test showed that with the increase in FS and FH, the coverage density and the droplet distribution uniformity in the upper and lower layers of wheat showed a downward trend under the condition of considering the boundary overlap of spraying width (SW) in multi-routes. Through the comparison of operation efficiency and droplet distribution quality, two combinations of parameters A1 (FS: 3 m/s, FH: 1.5 m) and B1 (FS: 4 m/s, FH: 1.5 m) were selected for the aphid control effect test. The results of the control test showed that the average control effect of A1 (92.05%) on aphids was 10.3% higher than that of B1 (81.75%) 7 days after pesticide application, which indicated that improving the droplet distribution uniformity in the lower layer of wheat could significantly improve the control effect of aphids. This study result could provide reference for the same type of crop protection UAV to control the same type of wheat diseases and insect pests in the same growing stage. [ABSTRACT FROM AUTHOR]

• Sanqi flowers have a higher quality under organic vs conventional management. • The flavonoid biosynthesis pathway was positively influenced by organic management. • The full blooming stages is the best time to harvest the Sanqi flowers. The simulative habitat cultivation of Panax notoginseng (Sanqi) under pine forests using organic management (OM) enhances the quality of Sanqi roots. However, the impact of the OM on the quality of Sanqi flowers remains unknown. The Sanqi flowers cultivated under OM compared with those cultivated under CM (conventional management) exhibited higher levels of flavonoids, saponins, and polysaccharides, as well as dry/fresh weight. Principal component analysis demonstrated that metabolites were predominantly influenced by the cultivation patterns followed by the flowering stage. Several of the differentially abundant metabolites and expressed genes were upregulated in Sanqi flowers cultivated under OM. The flavonoid biosynthesis pathway was highly affected by the cultivation systems and flowering stages, mediated by the essential genes C4H, HCT, C3′H, DFR, and FLS. Flavonoid levels peaked at full bloom, indicating that this is the optimum stage for harvesting Sanqi flowers. Our findings are of great value for developing optimal cultivation and harvest practices. [ABSTRACT FROM AUTHOR]

Plants developing into the flowering stage undergo major physiological changes. Because flowers are reproductive tissues and resource sinks, strategies to defend them may differ from those for leaves. Thus, this study investigates the defences of flowering plants by assessing processes that sustain resistance (constitutive and induced) and tolerance to attack. We exposed the annual plant Brassica nigra to three distinct floral attackers (caterpillar, aphid and bacterial pathogen) and measured whole‐plant responses at 4, 8 and 12 days after the attack. We simultaneously analysed profiles of primary and secondary metabolites in leaves and inflorescences and measured dry biomass of roots, leaves and inflorescences as proxies of resource allocation and regrowth. Regardless of treatments, inflorescences contained 1.2 to 4 times higher concentrations of primary metabolites than leaves, and up to 7 times higher concentrations of glucosinolates, which highlights the plant's high investment of resources into inflorescences. No induction of glucosinolates was detected in inflorescences, but the attack transiently affected the total concentration of soluble sugars in both leaves and inflorescences. We conclude that B. nigra evolved high constitutive rather than inducible resistance to protect their flowers; plants additionally compensated for damage by attackers via the regrowth of reproductive parts. This strategy may be typical of annual plants. Results show that flowering Brassica nigra protect their inflorescences with constitutive resistance rather than with inducible resistance, and compensate for floral dammage with early changes in primary metabolism and regrowth. Metabolic profiles reflected high resource investment into reproduction. [ABSTRACT FROM AUTHOR]

Chili (Capsicum annuum L.) is a horticultural plant susceptible to high-temperature stress. This research studied how agronomic and physiological characteristics of chili decline due to high temperature and determined the threshold value of temperature decreasing 50% of its yield. The experiment layout followed a randomized design, consisting of five temperature stress levels (in the growth chamber), namely, 31°C (daily temperature as a control), 33°C, 35°C, 37°C, and 39°C, with an exposure duration of 10 h. The temperature stress started when the plant reached the flowering phase. The plant parameters observed included agronomic and physiological characteristics. The study results showed that high-temperature decreased production significantly with the decline in all agronomic and physiological traits. The threshold temperature at 32.86°C has reduced the production of chili plants by 50% compared with the control. The study found that an increase in temperature of 2°C for 10 h in the flowering phase reduces chili production by 68.78%, and temperature stress at a maximum of 39°C for 10 h during flowering reduces chili production up to 87.52%. Hence, based on the study results, future research on chili should focus on developing varieties that are adaptive to high temperatures. [ABSTRACT FROM AUTHOR]

Climate change has resulted in a continuous increase in the frequency and intensity of chilling events in cold regions. In Northeast China, chilling at the booting and flowering stages negatively affects japonica rice grain yield. In this field experiment study, we conducted a 2‐year temperature‐controlled experiment to investigate the effects of chilling temperature and duration applied at the booting and flowering stages on japonica rice. The results showed that chilling at the two study stages delayed the rice phenology and decreased the grain yield. In particular, japonica rice was more sensitive to chilling at the booting stage than at the flowering stage. The rice grain yield was reduced by more as the chilling temperature decreased and the chilling duration increased. As for the yield components, the spikelet fertility and grain number per spike were more sensitive to chilling at the booting stage than at the flowering stage. Variations in the grain yield per plant were primarily contributed by the differences in spikelet fertility and grain number per spike, especially the spikelet fertility. In addition, cooling degree days showed statistically significant negative correlations with grain yield per plant, grain number per spike and spikelet fertility. For every 10°C·day increase in CDD at the booting (flowering) stage, the grain yield per plant, spikelet fertility and grain number per spike decreased by 7.1%, 6.2% and 3.4% (3.9%, 5.0% and 1.2%) respectively. As the spikelet fertility and grain number per spike decreased, the sink capacity decreased as well with the increasing of allocated assimilation to the stem and leaf while decreasing the assimilation allocated to the panicle. Increasing cooling degree days at the booting and flowering stages increased the allocations of assimilation to the stem and leaf. As a result, less assimilation was allocated to the panicle. This study suggests that breeding cultivars to improve the spikelet fertility and grain number per spike could help to minimize the potential rice grain yield loss due to the increase in chilling events occurring at the booting and flowering stages. [ABSTRACT FROM AUTHOR]

Drought is one of the most critical environmental factors constraining maize production. When it occurs at the flowering stage, serious yield losses are caused, and often, the damage is irretrievable. In this study, anthesis to silk interval (ASI), plant height (PH), and ear biomass at the silking date (EBM) of 279 inbred lines were studied under both water-stress (WS) and well-water (WW) field conditions, for three consecutive years. Averagely, ASI was extended by 25.96%, EBM was decreased by 17.54%, and the PH was reduced by 12.47% under drought stress. Genome-wide association studies were carried out using phenotypic values under WS, WW, and drought-tolerance index (WS-WW or WS/WW) and applying a mixed linear model that controls both population structure and relative kinship. In total, 71, 159, and 21 SNPs, located in 32, 59, and 12 genes, were significantly (P < 10−5) associated with ASI, EBM, and PH, respectively. Only a few overlapped candidate genes were found to be associated with the same drought-related traits under different environments, for example, ARABIDILLO 1, glycoprotein, Tic22-like, and zinc-finger family protein for ASI; 26S proteasome non-ATPase and pyridoxal phosphate transferase for EBM; 11-ß-hydroxysteroid dehydrogenase, uncharacterised, Leu-rich repeat protein kinase, and SF16 protein for PH. Furthermore, most candidate genes were revealed to be drought-responsive in an association panel. Meanwhile, the favourable alleles/key variations were identified with a haplotype analysis. These candidate genes and their key variations provide insight into the genetic basis of drought tolerance, especially for the female inflorescence, and will facilitate drought-tolerant maize breeding. [ABSTRACT FROM AUTHOR]

Plants phenology is extremely important tool for crop management, crop manipulation, and marketing. The objective of this research was to investigate the phenology and fruit quality of the several Annonaceae species under subtropical conditions of Homestead, Florida, USA. The study was carried out in an experimental sugar apple (Annona squamosa L.), orchard with cultivars: 'LeahReese', 'Lessard Thai' and 'Red' and the atemoya 'Gefner' (A. cherimola x A. squamosa L). Ten uniformly vigorous and healthy plants of each cultivar were selected. The fruit harvest period was similar for all the cultivars, except for sugar-apple 'LeahReese', which had the shortest harvest period of only 41 days. Multivariate analysis showed that 'Lessard Thai' and 'Red' sugar apple cultivars had smaller sizes and lower chemical quality. Cultivar "LeahResse" had the highest fruits, in addition, a strong correlation with the atemoya hybrid "Gefner". The sugar apples 'Lessard Thai' and 'Red' had similar phenology and had a 166-day pruning to harvest cycle. In contrast, 'LeahReese' sugar apple and 'Gefner' atemoya had significantly longer cycles of 182 and 196 days, respectively. The sugar apple 'LeahReese' had the best physical characteristics of the cultivars investigated, while the atemoya 'Gefner' had the best physiochemical characteristics and the longest shelf life. [ABSTRACT FROM AUTHOR]

Background and Aims Cold stress in rice (Oryza sativa) plants at the reproductive stage prevents normal anther development and causes pollen sterility. Tapetum hypertrophy in anthers has been associated with pollen sterility in response to cold at the booting stage. Here, we re-examined whether the relationships between anther abnormality and pollen sterility caused by cold stress at the booting stage in rice can be explained by a monovalent factor such as tapetum hypertrophy. Methods After exposing plants to a 4-d cold treatment at the booting stage, we collected and processed anthers for transverse sectioning immediately and at the flowering stage. We anatomically evaluated the effect of cold treatment on anther internal morphologies, pollen fertilities and pollen numbers in the 13 cultivars with various cold sensitivities. Key Results We observed four types of morphological anther abnormalities at each stage. Pollen sterility was positively correlated with the frequency of undeveloped locules, but not with tapetum hypertrophy as commonly believed. In cold-sensitive cultivars grown at low temperatures, pollen sterility was more frequent than anther morphological abnormalities, and some lines showed remarkably high pollen sterility without any anther morphological alterations. Most morphological anomalies occurred only in specific areas within large and small locules. Anther length tended to shorten in response to cold treatment and was positively correlated with pollen number. One cultivar showed a considerably reduced pollen number, but fertile pollen grains under cold stress. We propose three possible relationships to explain anther structure and pollen sterility and reduction due to cold stress. Conclusions The pollen sterility caused by cold stress at the booting stage was correlated with the frequency of entire locule-related abnormalities, which might represent a phenotypic consequence, but not a direct cause of pollen abortion. Multivalent factors might underlie the complicated relationships between anther abnormality and pollen sterility in rice. [ABSTRACT FROM AUTHOR]

Preliminary studies observed a lower growth activity during the vegetative stage with higher growth attributes at the pod-filling stage among the high nitrogen (N) utilisation efficiency (NUtE) oilseed rape (Brassica napus L.) genotypes, compared with the low NUtE genotypes. Therefore, we hypothesised that there would exist a critical growth stage when distinctive phenotypic traits are exhibited to regulate yield formation and NUE. A field experiment and a hydroponic culture were conducted to characterise the differences in shoot and root physiological indicators of the high and low NUtE oilseed rape genotypes at seedling, bud, bolting, flowering and pod-filling stages. We found that flowering was the critical period when the reverse growth habit occurred between high and low NUtE genotypes. The high NUtE genotypes displayed larger values of root traits, stronger N uptake kinetics parameters, higher activity of leaf glutamine synthetase (GS) and glutamate synthetase (GOGAT), larger SPAD values and net photosynthetic rate, ultimately leading to higher seed yield and NUE. Our results indicate that flowering is the critical growth stage to distinguish the high from low NUtE oilseed rape genotypes, and plant breeders may focus on selecting root and shoot phenotypic traits from flowering stage onwards to achieve both high yields and NUE for oilseed rape genotypes. [ABSTRACT FROM AUTHOR]

Rice is highly sensitive to salt stress at flowering stage. With the objective of detection of quantitative trait loci (QTLs) in multi-environment for this stage, 180 backcross-derived lines (BC3F5) from salt tolerant donor Pokkali (AC41585) and recurrent parent IR 64 were subjected to evaluation in saline (EC = 8 dSm−1) and non-saline environments in wet season of 2014 and 2015 employing a novel phenotyping protocol. Nine multi-environmental consistent QTLs for spikelet degeneration, K+ concentration in flag leaf, stress susceptibility index for grain (SSI-Grain) and spikelet sterility (SSI-STE) on chromosomes1, 2, 3, 4 and 11 with 17–42% phenotypic variances were detected. Among several digenic epistatic interactions, one was associated with the main effect QTL (qSSI-STE-11-1) over the years. Similarly genotype × environment interaction associated with two additive QTLs, qDEG-S-2-2 and qSSI-STE-2-1 had positive effect on the resultant phenotype. Functional genes encoding calmodulin-binding protein and potassium transporter were predicted inside the consistent QTLs. Detected stable QTLs, associated markers, predicted genes and derived introgression lines with these QTLs could be utilized in future breeding programme. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate the changes in the chemical composition of essential oils (EO) and the correlation between some secondary metabolites and antioxidant activity of different plant parts of Perovskia abrotanoides Kar. at the vegetative and flowering stages in Vamnan (Iran) in 2018. The EO of this plant was analyzed using the GC-Mass Spectrometry method. As the findings showed, P. abrotanoides leaf, during the flowering stage, had a greater amount of phenolic compounds, flavonoids, and anthocyanins than other parts and even the vegetative stage. At the flowering stage, the maximum antioxidant activity was obtained in the leaf (69.10%), based on the DPPH method. During the vegetative stage, the root was also in the next rank (62.10%). In this research, aerial parts of P. abrotanoides were different in terms of EO composition percentage and retention time. Likewise, 21 and 26 constitutes were identified during the vegetative and flowering stages, respectively. The major constitute was Carotol (31.105%) at the flowering stage, where IR-alpha-pinene (0.268%) had the lowest value. Overall, the results showed that P. abrotanoides can be introduced as an important source of natural antioxidant for pharmaceutical and natural food supplements due to its acceptable amount of bioactive compounds such as phenolic, flavonoids, anthocyanins, and EO. [ABSTRACT FROM AUTHOR]

Based on the daily average temperature from March 19 to April 2, 2021 at three surface meteorological stations in western Guizhou and the daily average temperature, maximum temperature and minimum temperature from March 19 to April 2, 2021 at 12 main automatic meteorological stations of red cartridge kiwifruit base, the effects of low temperature and high temperature on flowering and pollination of red cartridge kiwifruit in early spring of 2021 were analyzed. The results showed that slight cold spell in later spring in western Guizhou occurred from March 21 to 23. The lower limit of the daily average temperature required for flowering period (12 °C or below) appeared in each base of red cartridge kiwifruit during March 21 -23, which affected the red cartridge kiwifruit trees in Faer, Houchang, Miluo, Shunchang, Panlong and Jichang bases flowering and pollinating before March 20. From March 29 to April 2, the daily maximum temperature of Faer and other eleven bases was 30 °C or above, which caused the wilting and abscission of flowers and young fruits of of red cartridge kiwifruit trees in Faer, Houchang, Miluo, Shunchang, Panlong, shaomi, Jichang and Aga bases blooming and pollinating before March 24, but the flowers of red cartridge kiwifruit trees in Langdai, Longhe, Pugu and Shuangfeng bases blooming and pollinating after March 28 were not damaged. [ABSTRACT FROM AUTHOR]

Heracleum persicum, commonly named Persian hogweed, is a principal native medicinal plant in Iran. Collecting H. persicum at the most appropriate growing stage is the key factor to achieve the high phytochemical quality to meet consumer's needs. In the present experiment, the aerial parts of this plant were harvested at up to six different developmental stages during the growing season to determine the phytochemical profiles. Our results indicated that the highest essential oil content was obtained in the mid‐mature seed stage (3.5%). The most elevated extract content was recorded in the floral budding stage (10.4%). In the vegetative stage, limonene (18.1%), in floral budding stage, caryophyllene (14.1%), anethole (14.6%), and β‐bisabolene (12.7%), in the full flowering stage, myristicin (15.0%), and hexyl butyrate (9.1%), in the early development of seeds stage, hexyl butyrate (32.1%), and octyl acetate (11.7%), in the mid‐mature seeds stage hexyl butyrate (38.8%), octyl acetate (14.5%), in the late‐mature/ripe seeds stage, hexyl butyrate (23.6%), and octyl acetate (10.5%) are recorded as the main components. The highest phenolic acids content was obtained in the floral budding stage (287.40 mg/g dried extract). The analysis of phenolic acids demonstrated cinnamic acid (8.0–225.3 mg/g extract), p‐coumaric acid (1.7–39.2 mg/g extract), p‐hydroxybenzoic acid (0.8–16.8 mg/g extract), and ferulic acid (2.4–15.8 mg/g extract) as the main phenolic acids. Cinnamic acid was found as the major phenolic compound in the vegetative stage following by floral budding, the full flowering stage, the early development of seeds, and late‐mature/ripe seeds stages. P‐coumaric acid was the most abundant phenolic compounds in the mid‐mature seeds stage. In this regard, the harvest time of H. persicum aerial parts can be selected to achieve the highest secondary metabolites of interest. The results of this study can be used as a guideline for grower to obtain the highest possible amount of desirable metabolites, beneficial in both food and pharmaceutical industries as well as their undeniable economical benefits. [ABSTRACT FROM AUTHOR]

A field study was conducted to quantify the effect of moisture stress on nutrient uptake and post-harvest available soil nutrient status of rice in Tamil Nadu Agricultural University, Coimbatore during Kuruvai (July-November) 2019 and Navarai (December-March) 2019-20 seasons. Nine treatments, viz., Moisture stress at panicle initiation stage for 10 days (T1), 15 days (T2), 20 days (T3) and 25 days (T4), moisture stress at flowering stage for 10 days (T5), 15 days (T6), 20 days (T7) and 25 days (T8) along with control - maintaining saturation (T9) were tested under randomized complete block design with three replications. Moisture stress was imposed by withdrawing water and not irrigating in the defined period. The result showed that significantly higher total drymatter production and N, P and K nutrient uptake (grain, straw and total) during both the seasons were observed in T9 treatment than all other moisture stress imposed treatments. The least uptake of N, P and K in grain, straw and total was recorded in T4 and was statistically at par with T3. There was reverse trend on post-harvest soil nutrient status (NPK). The study revealed that moisture stress was more sensitive during panicle initiation stage than flowering stage, which directly influenced the uptake of nutrients in rice and there was a reverse trend on post-harvest soil available nutrients (NPK). [ABSTRACT FROM AUTHOR]

Field investigation on the influence of soil moisture stress (MS) on leaf temperature of rice at 0600 hours was made in Tamil Nadu Agricultural University, Coimbatore during Kuruvai (July-November) 2019 and Navarai (December-March) 2019-20 seasons. The treatments are T1: MS for 10 days from PI, T2: MS for 15 days from PI, T3: MS for 20 days from PI, T4: MS for 25 days from PI, T5: MS for 10 days from flowering, T6: MS for 15 days from flowering, T7: MS for 20 days from flowering, T8: MS for 25 days from flowering and T9: Control (Maintaining 2cm of water throughout the crop period). The experiment was laid-out in Randomized Completely Block Design with three replications. Leaf temperature was measured using an infrared thermometer at 0600 hours. Moisture stress had a significant influence on the leaf temperature of rice in the early morning hours. In Kuruvai season, an increase in leaf temperature was to the tune of 0.13oC to 2.20oC during Panicle Initiation (PI) stage (T1, T2, T3 and T4) and 0.16oC to 2.27oC during flowering stage (T5, T6, T7 and T8) over control due to MS. Similarly, increased leaf temperature to the tune of (0.13oC to 2.97oC and 0.07oC to 2.96oC during PI stage and flowering stage, respectively) was observed due to MS treatments than MS relieved treatments and control during Navarai season. The results confirmed that the direct influence on leaf temperature of rice was due to MS irrespective of the stages and seasons. The correlation between grain yield and leaf temperature due to the MS was found to be negative. [ABSTRACT FROM AUTHOR]

Total 20 maize varieties were subjected to drought stress at flowering stage, and then the relative water content, soluble sugar content, chlorophyll content, malondialdehyde (MDA) content and superoxide dismutase (SOD) activity in their leaves, as well as their yields were determined. The drought tolerance of the physiological and biochemical indexes was scored by five-level scoring method, and the drought tolerance index was calculated by the yield index to comprehensively evaluate the drought tolerance of maize during flowering stage. The results showed that the scores of drought tolerance of the maize varieties ranged from 1. 929 3 to 5.659 5. Among them, the scores of Zhengda 619, Guidan 162 and Guidan 0810 were greater than 5.0, followed by Dika 008, Xianyu 30T60, Xianzhengda 901, Qingnong 68, South America No. 1 and Wanchuan 1306 of which the scores were in the range of 4.0 -5.0. The drought tolerance indexes were in the range of 0.410 4 - 1.096 3. Among the test maize varieties, the drought tolerance indexes of Guidan 0810, Pacific 99 and Zhengda 619 were greater than 1.0, and those of Xianyu 30T60, Dika 008 and South America No. 1 were in the range of 0. 9 -1.0. The correlation between the two kinds of evaluation results was 0. 588 7 and was extremely significant. The five-level scoring method and the drought tolerance index can be used simultaneously for the evaluation of drought tolerance of maize during flowering stage. The two aspects of evaluation results showed that Guidan 0810, Zhengda 619, Xianyu 30T60, Dika 008 and South America No. 1 were drought-tolerant varieties, among which Guidan 0810 and Zhengda 619 were extremely highly drought-tolerant varieties. [ABSTRACT FROM AUTHOR]

Background: Salt stress, a major plant environmental stress, is a critical constraint for rice productivity. Dissecting the genetic loci controlling salt tolerance in rice for improving productivity, especially at the flowering stage, remains challenging. Here, we conducted a genome-wide association study (GWAS) of salt tolerance based on exome sequencing of the Thai rice accessions. Results: Photosynthetic parameters and cell membrane stability under salt stress at the flowering stage; and yield-related traits of 104 Thai rice (Oryza sativa L.) accessions belonging to the indica subspecies were evaluated. The rice accessions were subjected to exome sequencing, resulting in 112,565 single nucleotide polymorphisms (SNPs) called with a minor allele frequency of at least 5%. LD decay analysis of the panel indicates that the average LD for SNPs at 20 kb distance from each other was 0.34 (r2), which decayed to its half value (~ 0.17) at around 80 kb. By GWAS performed using mixed linear model, two hundred loci containing 448 SNPs on exons were identified based on the salt susceptibility index of the net photosynthetic rate at day 6 after salt stress; and the number of panicles, filled grains and unfilled grains per plant. One hundred and forty six genes, which accounted for 73% of the identified loci, co-localized with the previously reported salt quantitative trait loci (QTLs). The top four regions that contained a high number of significant SNPs were found on chromosome 8, 12, 1 and 2. While many are novel, their annotation is consistent with potential involvement in plant salt tolerance and in related agronomic traits. These significant SNPs greatly help narrow down the region within these QTLs where the likely underlying candidate genes can be identified. Conclusions: Insight into the contribution of potential genes controlling salt tolerance from this GWAS provides further understanding of salt tolerance mechanisms of rice at the flowering stage, which can help improve yield productivity under salinity via gene cloning and genomic selection. [ABSTRACT FROM AUTHOR]

In rice growing regions where water and temperature are growth limiting factors, the use of the innovative water-saving ground cover rice production system (GCRPS) leads to a substantial increase in yields and water use efficiency. However, so far the effect of GCRPS on root growth and its possible contribution to the observed increases in yield and water use efficiency remained unclear. In order to fill in this knowledge gap, we conducted a three-year experiment comparing two production systems: traditional paddy (Paddy) and GCRPS combined with two nitrogen fertilizer regimes (0, 150 kg N ha −1 ). The parameters investigated were root dry matter, length density and surface area at maximum tillering and flowering stage as well as grain yield and water use efficiency. Our study revealed the following findings: 1) Root dry matter, root length density and surface area were significantly higher in GCRPS than in Paddy at all soil depths. 2) Across the production systems, root dry matter, root length density and surface area at soil depth of 0–40 cm at flowering stage were significant positively correlated to grain yield and total water use efficiency which suggested that improved root morphology traits, especially at flowering stage, contribute to higher grain yield and water use efficiency in GCRPS. Our results show that GCRPS has a positive effect on the development of rice roots and that the improved root development is of vital importance for higher yields. Furthermore, the improved root development in GCRPS may avoid potential lodging phenomena and increase soil organic carbon stocks, thus improving key soil functions. [ABSTRACT FROM AUTHOR]

The differing water relations between flowers and leaves on a plant reflect the lack of co-ordination between reproductive and vegetative organs during the evolution of angiosperm species. The amount of water that flowers consume has been reported to vary across species, and compared with studies of leaves, accurate measurements of flower water relations at the branch level are lacking. Further, the mechanisms by which flowers regulate their hydraulic function and structure to maintain water balance remain unclear. To explore the ecophysiological basis underpinning the differences between flowers and leaves, we measured hydraulic and morphological traits and monitored sap flow in flowers and leaves from the same branches of two Magnoliaceae species that flower before leaf emergence (Magnolia denudata Desr. and Magnolia soulangeana Soul.-Bod.). Sap flux density (Js) of flowers was 22% and 55% of that predicted for leaves in M. denudata and M. soulangeana respectively. Js of flowers commenced before predawn and ceased early in the afternoon, reflecting their night-time flowering pattern and a dramatic decrease of Js with increasing vapour pressure deficit (D) under the high light of midday. Relative to leaves, tepals were thicker and more hydrated, and had bigger but scarcer stomata, leading to lower stomatal conductance (gs) and transpiration rate (E), less negative water potential (Ψtepal) and lower hydraulic conductance. This study revealed different hydraulic patterns in the flowers and leaves of the two Magnolia species. Although flowers consumed less than half the water that leaves did, they used different strategies to maintain sufficiently high Y to sustain hydraulic safety. Magnolia flowers retained more hydrated tepals by exhibiting less water loss than leaves via lower hydraulic conductance. In contrast, Magnolia leaves maintained high transpiration rates through efficient stomatal responses to environmental changes compared with flowers. [ABSTRACT FROM AUTHOR]

Peanut production areas frequently suffer from drought, which can cause severe yield losses, increased aflatoxin, and compositional changes in seed. Midseason drought is generally the most detrimental to seed yields and in altering seed protein composition. The purpose of this study was to investigate the effect of midseason drought on arginine content in peanut genotypes with different levels of drought resistance. The experiment was conducted under field conditions for 2 years. Two water regimes (wellwatered conditions and no irrigation during 30-60 days after planting) were assigned as main plots, and five peanut genotypes were arranged in subplots. Arginine content of mature peanut seed was analyzed at harvest. Midseason drought increased arginine content in all genotypes in both years. Variation in arginine content among peanut genotypes also indicated the possibility for breeding programs to improve arginine content in peanut. [ABSTRACT FROM AUTHOR]

Salicylic acid (SA) induced drought tolerance can be a key trait for increasing and stabilizing wheat production. These SA induced traits were studied in two Triticum aestivum L. varieties; drought tolerant, Kundan and drought sensitive, Lok1 under two different water deficit regimes: and rehydration at vegetative and flowering stages. SA alleviated the negative effects of water stress on photosynthesis more in Kundan. SA induced defense responses against drought by increasing antioxidative enzymes and osmolytes (proline and total soluble sugars). Differential proteomics revealed major role of carbon metabolism and signal transduction in enhancing drought tolerance in Kundan which was shifted towards defense, energy production and protection in Lok1. Thioredoxins played important role between SA and redox signaling in activating defense responses. SA showed substantial impact on physiology and carbon assimilation in tolerant variety for better growth under drought. Lok1 exhibited SA induced drought tolerance through enhanced defense system and energy metabolism. Plants after rehydration showed complete recovery of physiological functions under SA treatment. SA mediated constitutive defense against water stress did not compromise yield. These results suggest that exogenously applied SA under drought stress confer growth promoting and stress priming effects on wheat plants thus alleviating yield limitation. Biological significance Studies have shown morphological, physiological and biochemical aspects associated with the SA mediated drought tolerance in wheat while understanding of molecular mechanism is limited. Herein, proteomics approach has identified significantly changed proteins and their potential relevance to SA mediated drought stress responses in drought tolerant and sensitive wheat varieties. SA regulates wide range of processes such as photosynthesis, carbon assimilation, protein metabolism, amino acid and energy metabolism, redox homeostasis and signal transduction under drought. Proteome response to SA during vegetative and reproductive growth gave an insight on mechanism related water stress acclimation for growth and development to attain potential yield under drought. The knowledge gained can be potentially applied to provide fundamental basis for new strategies aiming towards improved crop drought tolerance and productivity. [ABSTRACT FROM AUTHOR]

Background: Reduction in rice yield caused by high temperature-induced spikelet sterility has been a serious concern in rice production. To date, several screening methods have been used, although their reproducibility is sometimes poor due to artifacts mainly caused by varietal differences in heading dates and panicle heights (i.e., the distance from the lamps). Methods: We have developed a novel assay system for heat-induced spikelet sterility by using artificial rice paddies in phytotrons to conduct a highly reproducible assay throughout a year. Plants restricted to the main culm were treated under a series of heat conditions, and height uniformity of each plant was ensured by using height-adjustable pots. Results: Results suggested that a 3-day heat treatment of 35 °C-day/29 °C-night cycles was the most suitable condition. Under the treatment, two distinct groups were identified among nine heat tolerant cultivars, with no varietal difference in panicle temperature, indicating that the system is capable of eliminating the varietal difference in panicle temperature. Conclusions: It is concluded that the assay system would be a powerful tool for selecting heat tolerant varieties, as well as the analysis of genetic factors from various cultivars, eliminating potential artifacts. [ABSTRACT FROM AUTHOR]

A field experiment was conducted at the experimental farm, Dept. of Field Crop, Coll. of Agriculture, Univ. of Baghdad ,during 2011-2012, to study the effect of potassium fertilizer levels and appilication stage on bread wheat grains quality Triticum asetivum L.(Var- Abu- Ghraib-3) and some other characteres . Factorial experiment was conducted in RCBD design with three replication involved two levels of potassium 120,180 kg.ha-1 and control treatment the second factor was three stage of application (tillering ,Booting , flowering). The results shows non significant differ between potassium leveles for all studied traits, except havest index.The potassium level 180 kg.ha-1 produced plants with highest harvest index (38.17%), in comparison to the level 120 kg.ha-1, (36.82%).The application stage at flowering time produced grains with higher protein (12.18%), when compard to the tillering and booting stages (11.32% and 12.17%) respectively. The potassium application stage at tillering was superior in protein yield and harvest index 0.935 mg.ha-1 and 40.37%, respectively. It can be conclude that potassium addition stage was more important than, it,s dosages. [ABSTRACT FROM AUTHOR]

Rice is most sensitive to heat stress at the flowering stage, with different degrees of heat damage in spikelets and leaves. To investigate the heat damage in spikelets and flag leaves, two rice genotypes, N22 (heat-tolerant) and GT937 (heat-sensitive), were subjected to a heat-stress treatment (40 °C for 15 days). The results showed that more damaging was found in spikelets than in flag leaves and the heat stress significantly decreased the seed-setting rate by 12.41% in N22 and by 65.02% in GT937. However, the difference in the net photosynthetic rate of the flag leaf between heat-stressed and control was not significant. Moreover, the difference of temperatures in spikelets and flag leaves was attributed to the differences in heat dissipating. Under heat stress, the transpiration rate was significantly higher in flag leaves than in spikelets, and the temperature in flag leaves were at least 4 °C cooler than in spikelets. Although the spikelet temperatures did not differ significantly between the two genotypes under heat stress, spikelets of GT937 were more severely damaged than those of N22, which might result from the differences in the antioxidant capacities between genotypes. Results showed that little difference of superoxide dismutase, peroxidase and catalase activities of spikelets was found in N22, while significant reduction was found in GT937 under heat stress, compared with control. These results suggest that organ temperature is controlled mainly by transpirational cooling, and that heat stress is an indirect result of oxidative stress, rather than a direct result of heat damage. [ABSTRACT FROM AUTHOR]

BACKGROUND: Kiwifruit (cv. Hayward) artificial pollination is a crucial technique useful to increase fruit quality and size. However, artificial pollination efficiency depends on the timing of application and the pollination system. OBJECTIVE: The main objective is identify the best practices to be applied in the orchard to reach the best pollination by deciphering the relation between the floral stage and the pollination technique. METHODS: Many parameters were analyzed in different environments in Italy for many years, such as pollen quality (germinability, humidity, conservation at -18°C), pollination system (dry or liquid, using different machines) and flowering stage. The interaction of the pollination systems and the flowering stage were evaluated by labeling flowers according to their flowering stage and weighting the fruit later. RESULTS: The petals fall and the early petal fall stages is the best moments for dry and liquid pollination respectively. The dry blower system gave the best results. The low pollination rate observed using the pollen-lycopodium mix is due to the interfering of the lycopodium on pistils. Pollen quality was achieved keeping it at low temperature during its harvesting and must have low humidity when stored at low temperature. CONCLUSIONS: The dry pollination with pure pollen reach the best result because at the end of flowering the pistil exudate increase the pollen adhesion. [ABSTRACT FROM AUTHOR]

In this paper, ‘Lu Feng No. 1’which is mainly cultured longan varieties in Luzhou was chosed as the research object. And we chose some experimental measurements on the basis of the local methods to promote floral bud differentiation. Before flower bud morphological differentiation, taking several regulation measures of spraying growth regulator in different proportions, girdling the primary branches and root pruning with coating the earth, we regularly measured endogenous hormones in terminal bud at flower bud differentiation period by every 1 5 d. When the differentiation finished, we calculated the rate of flower and fruit setting to discuss effects of regulation measures on change of endogenous hormones in terminal bud at flowering stage and flower formation and fruit setting. We analysed all experimental data for researching mechanism of flower formation. The result showed that all of these measures improved flower rate and fruit setting rate in different degrees remarkably. However, the control measures of ethylene regulator combination with appropriate concentrations (150 mg·L-1 and 100 mg·L-1)could improve the number of trees female flowers, female flowers rate and fruit-bearing rate of trees, among which the female flowers rate improved respectively by 32. 57% and 38. 22% than CK, the tip-blunting rate of each treatment was significantly lower than CK, and the tip-blunting rate (18. 58%)of treatment B (100 mg·L-1 ethylene regulator combination)was the minimum, which was 34. 18% lower than CK, and the growth rate of bud axis and tip-blunting rate have significant positive correlation. The different treatments improved the flowering and fruit-bearing status of longan body in different degrees, inhibited flowering reversion occurring effectively, and the effects of the treatment spraying mixed liquor consisted of 150. 00 mg·L-1 mutli-effect triazole an 100. 00 mg·L-1 ethephon and 1.0 mg·L-1 6-benzyl-aminopurine evenly in the crown most excellent. For the hormones in terminal buds, these contents and hormone balance were changed by the different measures. The results were as follows: with higher GA3 and ABA contents in the spindle differentiation stage, then GA3 content and ABA content keeping at a low level in multi-level side inflorescence rapidly-differentiation stage, lower ZT level in the entire morphological differentiation, and that was good for preventing longan flower from reversing and promoting longan bud differentiating. The change of IAA content affection was relatively complex, and its regularity was not strong. Viewing the point of hormones content proportion, smaller ratio of IAA/GA3 in the spindle differentiation stage, the bigger ratio of ZT/ABA before purple inflorescence primordia appearing-period and the lower ratio of ZT/ABA and GA3/ABA in hole morphological differentiation, which were beneficial to longan flowering. The study would provide theoretical basis for Luzhou longan high quality and high yield cultivation. [ABSTRACT FROM AUTHOR]

Mentha × piperita (L.) Huds. of the family Lamiaceae is a very important species for commercial exploitation due to the high content of essential oil. Besides the essential oils, there are also other significant secondary metabolites in peppermint, especially flavonoids and hydroxycinnamic derivatives. In this study, we evaluate the variability of essential oil constituents and of phenolic compounds in the leaves of M. × piperita during the development of inflorescence. Similar studies, dealing with the variation of the essential oils and its composition, have been performed in the past, but no attention was paid to the variation of other secondary metabolites. We examined M. × piperita cv. 'Perpeta', the domestic cultivar. The plants were cultivated in the climatic conditions of south-west Slovakia. The contents of secondary metabolites were investigated in the week periods, from the beginning of inflorescence formation to the end of flowering. The yield and the quality of essential oil have been carried out by distillation and gas chromatography mass spectrometry (GC-MS). The phenolic substances were analysed using spectrophotometric methods according to European Pharmacopoeia. The highest contents of phenolic substances have been found in leaves of plants during the flowering phenophase, the same stage when essential oil of mint also achieves the highest quality. [ABSTRACT FROM AUTHOR]

Opuntia flowers belonging to two species of prickly pear were evaluated at four flowering stages: vegetative, initial flowering, full flowering and post-flowering stage, for possible use as a potential source in the food enrichment. Chemical composition including moisture, ash, protein, fat, soluble sugars, total fibers, mineral amounts and fatty acid profiles of Opuntia ficus-indica and Opuntia stricta flowers were investigated. Functional properties (swelling capacity (SWC), water holding capacity (WHC), water solubility index (WSI) and oil holding capacity (OHC)) were also studied. Results showed that during the maturation of flowers, there is a decrease in protein contents whereas fat contents increase, for both species. High minerals amounts were noticed in Opuntia flowers and they can be considered as an excellent source of minerals. The fatty acids profiles were dominated by the palmitic acid (38–59%). The techno-functional properties (SWC, WSI, WHC and OHC) were found to be important and they can be modulated according to the temperatures. Owing to its chemical profile and functional properties, Opuntia flowers could be used as an ingredient to improve different physical and nutritional properties of foods. [ABSTRACT FROM AUTHOR]

[Display omitted] • V cmax25 , N a and Chl a of winter wheat and paddy rice exhibited distinguishable seasonality. • The seasonality of leaf N a and Chl a were inconsistent with that of V cmax25. • Differentiating pre- and post-flowering stages significantly improved the estimation of V cmax25 from Chl a. Accurate representation of photosynthetic capacity and its seasonal variations is critical for modeling carbon sequestration of cropland ecosystems through photosynthesis. Previous studies indicated that the maximum carboxylation rate at 25 °C (V cmax25) is the key determinant of photosynthetic capacity and can be mapped according to leaf nitrogen (N) and chlorophyll (Chl) contents. However, whether relationships of V cmax25 with leaf nitrogen and chlorophyll contents in cropland ecosystems change over the whole growing season remain unclear. To address this question, we conducted intensive field campaigns in winter wheat and paddy rice farmlands of Eastern China, with leaf V cmax25 , the maximum electron transport rate at 25 °C (J max25), N, and Chl measured every 7 to 10 days from the tillering stage to maturity. Results showed that V cmax25 and J max25 varied significantly during the growing seasons and maximized at flowering stages. For both winter wheat and paddy rice, Chl a (Chl content at the area unit) showed significantly different relationships with V cmax25 pre- and post- flowering while N a (N content at the area unit) did not. When different empirical models were used for pre- flowering and post- flowering stages, V cmax25 estimated from Chl a was closer to observations (R2 = 0.875, RMSE = 9.479 µmol m−2 s−1) than that estimated from N a (R2 = 0.565, RMSE = 17.718 µmol m−2 s−1). The findings in this study imply that the combination of remotely sensed leaf Chl a content and phenology would improve the mapping of V cmax25 for crops at regional and even global scales. [ABSTRACT FROM AUTHOR]

Dracocephalum moldavica L. of the Labiatae family is an annual herbaceous plant. In Iran it is known as Badrashbi and Badrashboo. Recent publications have reported antibacterial and antimicrobial properties of its essential oil, which have a wide usage in industry. In this research, the effects of iron foliar application and different yields' harvest times on the essential oil content and some morphological treats (plant height, branch number, fresh and dry weights, essential oil content and leaf Iron content) were investigated under experimental study in faculty of Agriculture of Urmia University during 2012. A factorial experiment in a randomized complete block design with three replications was used in the present study. Results showed that foliar application of iron had a significant effect on branch number, fresh and dry weight, biomass and oil percentage. Similarly, harvest time had a significant influence on fresh and dry weight, essential oil content, essential oil yield and leaf iron content, but its effect was not significant on stem diameter and branch number. The best harvest time for Dracocephalum moldavica L. was at 100% of flowering and 6 ml/l of iron application showed the best results in all characters measured. [ABSTRACT FROM AUTHOR]

Opuntia ficus-indica f. inermis (cactus pear) flowers have wide application in folk medicine. However, there are few reports focusing on their biological activity and were no reports on their chemical composition. The nutrient composition and hexane extracts of Opuntia flowers at 4 flowering stages and their antibacterial and antifungal activities were investigated. The chemical composition showed considerable amounts of fiber, protein, and minerals. Potassium (K) was the predominant mineral followed by calcium (Ca), magnesium (Mg), sodium (Na), iron (Fe), and zinc (Zn). The main compounds in the various hexane extracts were 9.12-octadecadienoic acid (29-44%) and hexadecanoic acid (8.6-32%). The antibacterial activity tests showed that O. inermis hexane extracts have high effectiveness against Escherichia coli and Staphylococcus aureus, making this botanical source a potential contender as a food preservative or food control additive. [ABSTRACT FROM AUTHOR]

Radiant frost is a major abiotic stress, particularly at the reproductive stage, in field pea ( Pisum sativum L.) grown in Mediterranean environments. Here, response to frost was studied for flowering stage (FS) organs (buds, flowers and set pods) and pod development stage (PDS) organs (flat, swollen and mature pods) under controlled conditions, with plants exposed to a minimum temperature of -4.8°C for 4 h. This frost treatment adversely affected seed yield through (i) abortion of buds, flowers and set pods (ii) death of pods and (iii) reduction in seed size. FS organs were more sensitive to frost than PDS organs. Genetic variation was observed among 83 accessions collected from 34 countries worldwide for survival of FS buds, flowers and set pods. In 60 of 83 accessions, no buds, flowers or set pods survived the frost treatment. Five accessions: ATC 104 (origin: United Kingdom), ATC 377 (Estonia), ATC 968 (Italy), ATC 3992 (Kazakhstan) and ATC 4204 (China), showed the highest frost tolerance of FS organs and lowest numbers of abnormal seeds. The frost tolerant accessions identified in this study may be useful as parents for breeding field pea varieties that will be less likely to suffer yield loss due to radiant frost during the reproductive stage. [ABSTRACT FROM AUTHOR]

This study was carried out to investigate the morphological characteristics of collected Miscanthus spp. Fourteen accessions of Miscanthus spp. were collected in various localization in Korea, India, Nepal and USA. Collected Miscanthus spp. accessions were investigated their morphological characters, compared with pre-flowering stage and post-flowering stage. Plant height, stem diameter, number of node, tiller number, number of leaf, length of leaf, width of leaf and color of leaf have different characters significantly among the collected accessions. Miscanthus spp. accessions collected in Yangpyeong-gun (MS005), India (MS013), Iowa (MS010), M.×giganteous (MS011) showed comparatively taller height, range of more than 200 cm. There were no significant differences in the collected Miscanthus spp. accessions ranging from 2 to 3 numbers of tillers. Of the total accessions, most of collections showed 1-2 cm as over 65% in width of leaf, but collection Miscanthus spp. accessions in Andeok-myeon (MS002), Seongsan-eup (MS003) and Yangpyeong-gun(MS005) showed over 2 cm in width of leaf. Miscanthus spp. collected in Yangpyeong-gun (MS005) could be used as a bio-energy plant showing up large scale biomass in plant height, length of leaf and width of leaf. [ABSTRACT FROM AUTHOR]

Abstract: The chemical composition of hexane extracts from flowers belonging to two species of prickly pear, Opuntia ficus-indica (L.) Miller and Opuntia stricta (Haw.) Haworth has been studied by gas chromatography–mass spectrometry in four developmental stages of flower: vegetative, initial flowering, full flowering, and post-flowering stages. Remarkable differences were noted between the flowers’ compositions. The main compounds were carboxylic acid (28–97%), terpenes (0.2–57%), esters (0.2–27%), and alcohols (<1.8%). The study of the biological activities showed that extracts were active in vitro towards four bacteria and two fungal strains. It exhibited remarkable activity against Pseudomonas aeruginosa, Staphylococcus aureus, and Escherichia coli. Antioxidant activity of the flowers extracts was evaluated by the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical method. Our findings demonstrate the interest of Opuntia flowers extract as a source of bioactive substances and its potential preservative use in food. [Copyright &y& Elsevier]

With 3 figures and 5 tables Abstract To identify quantitative trait loci (QTL) controlling heat tolerance in rice, the progeny of BC1F1 and F2 populations derived from an IR64 × N22 cross were exposed to 38/24°C for 14 days at the flowering stage, and spikelet fertility was assessed. A custom 384-plex Illumina GoldenGate genotyping assay was used to genotype the F2 and selected BC1F1 plants. Four single nucleotide polymorphisms were associated with heat tolerance in the BC1F1 population using selective genotyping and single marker analysis, and four putative QTL were found to be associated with heat tolerance in the F2 population. Two major QTL were located on chromosome 1 (qHTSF1.1) and chromosome 4 (qHTSF4.1). These two major QTL could explain 12.6% (qHTSF1.1) and 17.6% (qHTSF4.1) of the variation in spikelet fertility under high temperature. Tolerant allele of qHTSF1.1 was from the susceptible parent IR64, and that of qHTSF4.1 was from tolerant parent N22. The effect of qHTSF4.1 on chromosome 4 was confirmed in selected BC2F2 progeny from the same IR64 × N22 cross, and the plants with qHTSF4.1 showed significantly higher spikelet fertility than other genotypes. [ABSTRACT FROM AUTHOR]

Abstract: Flowering time plasticity is a commonly occurring adaptive characteristic of fodder crops, including legumes, in arid and semiarid environments of the Mediterranean regions. Time of flowering is mainly influenced by genotype, temperature and photoperiod. Field experiments were carried out at Foggia (southern Italy) during successive growing seasons (from 8 to 16 growing cycles according to species) to study the relation among air temperature, photoperiod and duration of the morphological development of flowering in eight forage legume species: sulla (Hedysarum coronarium L.), sainfoin (Onobrychis viciifolia Scop.), pea (Pisum sativun L.), berseem clover (Trifolium alexandrinum L.), Persian clover (Trifolium resupinatum L.), faba bean (Vicia faba L.), common vetch (Vicia sativa L.) and hairy vetch (Vicia villosa Roth). Time to reach 10% flowering (EF) and 100% flowering (FF) were recorded. Rate of progress to flowering, defined as the inverse of time from sowing to EF and FF, was related to mean daily temperature, or to both mean daily temperature and mean photoperiod. Using the linear equations, the thermal time requirements (T t) and the base temperature (T b) expressed as heat units were determined by the x-intercept method for both EF and FF stages. Evaluation of flowering time was also based on days after planting (DAP), day of year (DOY) and on a photothermal index (PTI). For all species, a significant negative correlation (P ≥0.01) was found between planting date (PD) and DAP whereas PTI showed a significant negative relationship (P ≥0.05) only for faba bean, pea, berseem clover and common vetch. In sainfoin, sulla and berseem clover, the rate of progress to flowering was affected significantly (P ≥0.05) by both mean temperature and photoperiod. The T t requirements to reach the EF and the FF stage ranged from 871 to 1665°Cday and from 1043 to 1616°Cday, respectively, for the studied species. Both phenological stages considered depended upon accumulated thermal time above a species-specific base temperature. Furthermore, in all legumes the onset of flowering only occurred when dual thresholds of a minimum T t and a minimum photoperiod were reached, which were specific to each species. [Copyright &y& Elsevier]

Abstract: The Cd accumulation and biomass characteristics of a newly found Cd-hyperaccumulator Solanum nigrum L. were investigated at the flowering stage and the mature stage. The results showed that the concentration of Cd in the stems and leaves of S. nigrum harvested at the flowering stage was up to 83.1% and 85.5% of that at the mature stage, and the dry-weight sum of the stems and leaves of S. nigrum harvested at the flowering stage was 93.4% of that at its seed maturity. The Cd-removing ratio by the shoots of S. nigrum harvested at the flowering stage was 87.5% of that at the mature stage. It was also found by observing the growth duration of S. nigrum that the frostless period at the experimental site was at least twice as long as the growth duration from the seedling-transplanted phase to the flowering stage of the hyperaccumulator. Therefore, S. nigrum could be transplanted into contaminated soils twice in one year by harvesting the hyperaccumulator at its flowering stage based on climatic conditions of the site and traits of the plant growth. In particular, the extraction efficiency of Cd by harvesting the shoots of S. nigrum at its flowering stage twice in one year could increase 75.0% compared to that of at its single maturity. Thus, the method of multiple harvesting would be very important to increase phytoremediation efficiency in practice. [Copyright &y& Elsevier]

Spearmint ( Mentha spicata L. ) plants were grown in a greenhouse in a nutrient solution containing manganese (Mn) concentrations varying between 9 μM and 15.75 μM until the flowering stage. The rates of chlorophyll and carotenoid contents were similar for treatments up to 13.5 μM, followed by a statistically significant increase onwards. Chlorophyll a and total carotenoids reduced gradually with increasing Mn concentrations, showing statistically significant differences in the last treatment (15.75 μM Mn) Anthocyanin contents increased gradually and steadily with increasing Mn concentrations. Accumulation of Mn in Mentha spicata roots was greater than shoots, indicating significant metal immobilization by the roots. The main conclusion is that Mn accumulation starts to be toxic as concentration of Mn increases. [ABSTRACT FROM AUTHOR]

The color of bracts generally turns yellow or black from green during cereal grain development. However, the impact of these phenotypic changes on photosynthetic physiology during black bract formation remains unclear. Two oat cultivars (Avena sativa L.), 'Triple Crown' and 'Qinghai 444', with yellow and black bracts, respectively, were found to both have green bracts at the heading stage, but started to turn black at the flowering stage and become blackened at the milk stage for 'Qinghai 444'. Their photosynthetic characteristics were analyzed and compared, and the key genes, proteins and regulatory pathways affecting photosynthetic physiology were determined in 'Triple Crown' and 'Qinghai 444' bracts. The results show that the actual PSII photochemical efficiency and PSII electron transfer rate of 'Qinghai 444' bracts had no significant changes at the heading and milk stages but decreased significantly (p < 0.05) at the flowering stage compared with 'Triple Crown'. The chlorophyll content decreased, the LHCII involved in the assembly of supercomplexes in the thylakoid membrane was inhibited, and the expression of Lhcb1 and Lhcb5 was downregulated at the flowering stage. During this critical stage, the expression of Bh4 and C4H was upregulated, and the biosynthetic pathway of p-coumaric acid using tyrosine and phenylalanine as precursors was also enhanced. Moreover, the key upregulated genes (CHS, CHI and F3H) of anthocyanin biosynthesis might complement the impaired PSII activity until recovered at the milk stage. These findings provide a new insight into how photosynthesis alters during the process of oat bract color transition to black. [ABSTRACT FROM AUTHOR]