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Male reproductive development of rice (Oryza sativa L.) is very sensitive to drought. A brief, transitory episode of water stress during meiosis in pollen mother cells of rice grown under controlled environmental conditions induced pollen sterility. Anthers containing sterile pollen were smaller, thinner, and often deformed compared to normal anthe...
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... basal part of 5-day old seedlings, where a-tubulin gene expression was the highest (Figs. 2 and 4), was used for this experiment. Fig. 8 shows the hybridization of sections from un- stressed seedlings (A) or those subjected to water stress for 6 h (B) with the anti-a-tubulin antibody. Fig. 8C is the corresponding control with no secondary antibody added (no pre-immune serum was available). In both unstressed and stressed seedlings, the a- tubulin protein was present ...
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... basal part of 5-day old seedlings, where a-tubulin gene expression was the highest (Figs. 2 and 4), was used for this experiment. Fig. 8 shows the hybridization of sections from un- stressed seedlings (A) or those subjected to water stress for 6 h (B) with the anti-a-tubulin antibody. Fig. 8C is the corresponding control with no secondary antibody added (no pre-immune serum was available). In both unstressed and stressed seedlings, the a- tubulin protein was present most abundantly in the youngest growing leaves (inner whorls) and decreased with the age of the tissue (outer layers). Of the four leaves that were visible, the ...
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... that were visible, the most intense signal was localized in the youngest, fourth leaf. Within the leaf, the strongest signal was observed in the sclerenchymatous tissues bordering the vascular bundles, especially in the two youngest sheaths. Water stress suppressed the level of a-tubulin protein in all parts where the latter was present (cf. Fig. 8 A and ...
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... expressed differentially in various organs and its expression strongly correlated with growth. In young seedlings, expression peaked in the most actively growing zone and was barely observed in the non-growing portion (Fig. 2). The highest levels of expression were detected in the youngest leaves, which would then be growing at the fastest rates (Fig. 8). Similarly, levels of a-tubulin mRNA in panicle continued to increase during the rapid elongation phase and dropped drastically as panicle reached its maximum length just prior to anthesis (Fig. 3). Consistent with this observation, RiP-3 was strongly expressed in the floral organs (Fig. 1) shoot (Fig. 2) and young leaves (Fig. 5) that ...
Citations
... Furthermore, pollen metabolism relies on stored food reserves, such as starch and sucrose, which act as thermoprotectants against heat stress (Pressman et al. 2002). Heat stress has been shown to inhibit the starch deposition and total soluble sugars in pollen (Sheoran and Saini 1996). This could happen by reduced availability of assimilates or reduced enzyme activity involved in starch biosynthesis (Sheoran and Saini 1996). ...
... Heat stress has been shown to inhibit the starch deposition and total soluble sugars in pollen (Sheoran and Saini 1996). This could happen by reduced availability of assimilates or reduced enzyme activity involved in starch biosynthesis (Sheoran and Saini 1996). Biostimulants have been shown to accumulate starch and total soluble sugars under heat stress (Hasanuzzaman et al. 2021) which improves the thermotolerance of pollen grains. ...
The complex processes of pollen germination and pollen tube elongation are important events in the sexual reproduction of flowering plants and are essential to the success of seed formation. However, unfavourable environmental and climatic conditions affect pollen performance negatively. Integrating the application of various biostimulants represents one of the most innovative and promising strategies to improve crop productivity. Biostimulants are known to sustainably improve pollen viability, germination and elongation. However, there is limited information on the effects of biostimulants on pollen grains. The present review investigates the potential of biostimulants (such as seaweed extracts, smoke–water, polyamines, amino acids, melatonin, carbohydrate-based biostimulants and inorganic biostimulants) as signaling molecules that can improve crucial stages of pollen growth in a range of crops, both in optimal and suboptimal environments. Furthermore, this review investigates the stages of pollen development, including uninucleate microspores and different stages of mature pollen, following various biostimulant treatment during the flowering period. Regulation of biostimulant-induced pollen germination and elongation has also been discussed along with recent developments regarding the mechanism of action of biostimulants in various growth aspects of pollen. This review not only summarizes what is known currently, but it also lays the groundwork for future investigations to clarify the complex physiological and molecular processes involved in pollen performance as well as the regulatory systems that are impacted by biostimulants.
... D + HT stress during sporogenesis and gametogenesis cause pollen abnormalities and functional changes (Saini, 1997). Decreased carbohydrate level during drought stress resulted in malformation of anther walls and pollen tube development (Sheoran & Saini, 1996). High temperature stress negatively regulates the tapetum and pollen mother cell development, formation of anther walls (Abiko et al., 2005), pollen dehiscence, pollen tube development and pollen germination (Fahad et al., 2016). ...
... The variation in reproductive structures under combined stress might be due to the functional changes of sporogenesis and gametogenesis during flowering, which cause pollen abnormalities (Saini, 1997). Decreased carbohydrate level during drought stress resulted in malformation of anther walls and pollen tube development (Sheoran & Saini, 1996). ...
Chilli (Capsicum annum L.) is a vegetable crop that is valued for its colour and pungency. Water scarcity with high temperature has serious impact on growth, development and reproduction of crops. However, knowledge on the impact of combined stress on chilli physiology and reproduction is limited. Thus, the present study aims to assess the combined effects of drought (FC 60%) and high temperature (average > 35 °C) stresses during reproductive stage on the physiology, anatomy of reproductive structures and yield of chilli varieties and hybrids under rain out shelter condition. Results revealed that the combined stresses significantly reduced the chlorophyll index, chlorophyll stability index, leaf gas exchange parameters, water use efficiency, membrane stability and increased the osmotic adjustment, malondialdehyde content and total antioxidants across chilli genotypes. The male and female reproductive structures of stressed plants depicted structural aberrations like shrinkage and withering, however the extent of aberrations was lesser in tolerant than in most susceptible genotype. In addition, the stresses resulted in the reduction of pollen viability (45.79%), fruit set (63.86%) and retention (63.08%) in the most susceptible genotype CO1 hybrid with fruit set and fruit retention reduction of 24.09% and 29.95%. respectively when compared with control. Taken together, the combined drought and high temperature stresses reduced the physiological activity, caused anatomical variations and reduced yield in chilli genotypes, though the extent of impact varied across genotypes.
... This situation intensifies drought conditions; further restricting crop water availability and compounding the difficulties faced by farmers (Mallareddy et al., 2023). Water deficit during the meiotic phase results in significant reduction, ranging from 35% to 75%, in grain set of wheat and rice (Saini and Aspinall 1981;Sheoran and Saini 1996). Drought stress in rice disrupts the processes of fertilization and anthesis, leading to decreased harvest index and grain set by 60% (Garrity and O'Toole 1994). ...
Soil biodiversity encompasses a rich array of organisms present in the soil and have profound implications for ecosystem functioning and long-term sustainability of agro ecosystem. Rise in atmospheric carbon dioxide (CO2) concentration and temperature are two major drivers of global climate change scenario. This review article delves into the impact of elevated carbon dioxide (E[CO2]) and temperature on crop growth and yield and its effect on soil biodiversity. It elucidates the current understanding of how CO2 and temperature changes affect crop yield and soil biodiversity. Increased CO2 concentrations can stimulate or dampen plant growth with marked influence on crop yield and global food security. The E[CO2] affects the functional and structural composition of soil microbial community through its effects on plant C inputs to soil, soil moisture, or nutrient availabilities. Temperature influences the physiology, activity, and survival of both crops and soil organisms. Warmer temperatures disrupt the crop's optimal temperature with adverse effect of crop physiological processes. Shifts in temperature regimes may also affect the distribution and abundance of different soil organisms, potentially favoring some species while suppressing others. Enhanced temperature also accelerates decomposition rates, nutrient cycling processes, altering organic matter dynamics and nutrient availability in the soil. The combined effects of elevated CO2 and temperature on soil biodiversity are complex and context-dependent. The interplay between elevated CO2, temperature, and soil biodiversity in agricultural ecosystems are complex and multifaceted which requires further investigation. To mitigate these adverse effects, strategies such as conservation agriculture practices, sustainable farming methods, and precision nutrient management are required to promote soil biodiversity enhance resilience, and productivity under changing environments. Continued effort is essential to unravel the mechanisms involved in these interactions.
... This was evident in this study by observing lower HI, crop biomass, and pod weight per plant of waterstressed plants when grown under severe heat stress (HTHT) compared with no-heat stress (LTLT). Various researchers reported that yield loss in legume crops under drought stress was due to reduced biomass and poor partitioning towards grain [32][33][34]. Morphological attributes, such as plant height, leaf area, and crop biomass were reduced when plants experienced water stress [35]. ...
Information regarding the relative importance of elevated day/night-time temperatures combined with water stress on mungbean yield is limited. This study aimed to investigate the yield response of mungbean cultivars to different water stress and temperature regimes under controlled glasshouse conditions. Two mungbean cultivars, Celera II-AU and Jade-AU, were grown and evaluated under four temperature regimes with and without water stress, each replicated 10 times in a randomized complete block design. The four temperature regimes were as follows: (i) HTHT: Plants were consistently exposed to high day/high night temperatures (35/25 °C). (ii) LTHT: Plants experienced ambient day/ambient night temperatures (25/15 °C) for the first 35 days, followed by the HTHT environment. (iii) LTLT: Plants were maintained at ambient day/ambient night temperatures (25/15 °C) throughout the experiment. (iv) HTLT: Plants were subjected to high day/high night temperatures (35/25 °C) for the initial 35 days, followed by the LTLT environment. Under water stress conditions, mungbean yield declined significantly in the HTHT environment by 57% for Jade-AU and 76% for Celera II-AU compared to the LTLT environment. The highest seed yield (10.2 g plant−1 for Jade-AU and 11.4 g plant−1 for Celera II-AU) for both cultivars was observed when grown without water stress in the LTLT environment. However, yield decreased substantially when plants experienced combined heat and water stress during the reproductive stage (HTHT and LTHT environments). Without water stress, mungbean yield under the HTHT environment decreased by 30% for Jade-AU and 60% for Celera II-AU compared to the LTLT environment. Surprisingly, no significant difference in response to water stress was observed between the two cultivars. Furthermore, when grown under no-water stress and HTHT environments, the yield of Celera II-AU was reduced by 37% compared to Jade-AU. Similarly, a comparable response was seen between cultivars under no-water stress and LTHT environment. The results indicated that water and heat stress negatively affected mungbean seed yield. Moreover, it was observed that Jade-AU outperformed Celera II-AU regarding seed yield under heat-stress conditions. In conclusion, this study suggests that adjusting sowing time and selecting suitable heat-tolerant cultivars, such as Jade-AU, could enhance mungbean yield under heat and water stress conditions. The results demonstrate substantial impacts on mungbean productivity from changing climatic and water stress conditions and these findings can be utilized for improving mungbean productivity in dryland regions.
... Elevated temperature has a negative effect on rice production, but the impact of changes in rainfall is positive. Sometimes, water scarcity during meiotic phase of rice can cause reduction of 60% in harvest index and 35-75% in grain set [43]. Drought stress affects greatly in the process of fertilization and anthesis which occurs between 9 to 11 am [44]. ...
Climate change, through its perils and risks generates vulnerable impacts that can surpass limits to adaptation and results in depletion and damages. The observed effects of past climate trends on global crop production and the increased susceptibility of plants enfeebled by the direct impacts of varying climatic conditions are evident in several regions of the world and are of special concern in agricultural dependent tropical regions with low or no levels of adaptation. Steady depletion of soil health and ecosystem services, sudden loss in food production from heat and drought are threatening food productivity thereby, compromising global food security worldwide. The present study is an overview of possible effects of the varying climate on rice and wheat production in India and it focuses on the impacts of the major climatic variables viz., CO2, temperature and rainfall on yield and quality. The increase in these factors can lead to reduced yield of crops, increased incidence of pest and disease outbreak, stunt the growth or cause complete crop failure. Crop production and management is a huge challenge because it is always highly dependent on climate and environmental factors. Therefore, shifting weather patterns and other factors contributing to such challenges must be identified and rectified. There is a growing need to understand the ecological dynamics of climate change impacts, to identify hotspots of vulnerability and resilience and to identify management mediations. The mechanisms, potentials and limits of natural as well as technology-based solutions need to be explored and quantified.
... Iraq was ranked among the top ten countries that consume the most rice to 90% under normal irrigation conditions (Sheoran and Saini, 1996), in order to satisfy the need for rice from the growing world population. Total food production must be increased by 60% in the next 25 years, and to achieve this, several means and tools must be adopted, such as using high-yielding varieties or improving crop management and service, as well as adopting programs for breeding and genetic improvement of stocks. ...
A field experiment was carried out at the rice research station in Al-Mishkhab Najaf /Iraq affiliated to the Agricultural Research Department during the summer season 2022. the aim of the study was to investigate the performance of grains yield traits and its components for genotypes of rice, (Anber-33, Jasmine, Baraka, Furat, K1, K35, and K45) under the influence of levels of water stress, (daily flood irrigation, irrigation every 5 days, and irrigation every 10 days). The experiment was applied according to the RCBD Randomized Complete Block Design with three replicates according split-plot arrangement. The stress levels were occupied the main plot and the genotypes were placed in the secondary plot. The results of the statistical analysis showed that there were significant differences (LSD, P<0.05) for the genotypes, the genotypes (K1 and Furat) were significantly superior in the number of grains (142.2 seeds panicle-1), the sterility rate, were 15.15%, the grains yield and biological yield (5,547 and 13,212 tons ha-1) respectively. Sequentially, it was followed by the genotype (Furat), in characteristics the number of tillers.m-2 was 270.6, and the grains yield and biological yield were 4.306 and 11.448 tons.h-1 respectively. Beside, the results of the irrigation periods there was a highly significant on most of the characteristics of the grain yield and its yield components, as the irrigation level (every 10 days) was recorded the lowest average for most of the characteristics, including the number of tillers 197.3 tillers m-2 , the number of grains reached 70.8 seeds panicle-1 , the percentage of sterility 42.72%, in addition to grain yield and biological yield 2.645 and 9.483 tons.h-1 respectively. The results the interactions (genotypes X irrigation periods) showed that there is an significant effect on most of the traits, as the treatment (K1 X daily irrigation) recorded Significantly superiority in most of the traits such as the number of grains, the lowest percentage of sterility, the highest grains yield and the biological yield, and it gave 142.2 grain panicle-1 , 10.34%, 6,230 tons ha-1 MJAS and 13,960 tons ha-1 respectively. Whereas, the Interaction (K45 X irrigation every 5 days) superiority in the weight of straw was 8,790 tons h-1 , the interaction (Baraka X irrigation every five 10 days) gave the highest number of tillers reached 298.3 tillers m-2 , the sterility rate reached 70.86%, the lowest grains yield was 0.432 tons ha-1 , and the lowest harvest index reached 6.77%.
... Sucrose confers desiccation tolerance in ways reminiscent of orthodox seeds, that is, by forming a glassy state that limits cell mobility and protects membranes by replacing water in chemical bonds (Buitink and Leprince, 2004). Although the amount of soluble sugars is higher in anthers during a drought, the transfer of these sugars to the pollen grains is blocked due to a dysfunction of the tapetum and the suppression of enzymes of sugar metabolism and starch biosynthesis (Sheoran and Saini, 1996;Yu et al., 2019), which ultimately causes sterility and pollen abortion (Jin et al., 2013). An explanation of the above is the hormonal imbalance derived from drought stress, which affects not only the functionality of the tapetum and sugar metabolism (De Storme and Geelen, 2014), but also ROS detoxification system (Hu et al., 2011;Jin et al., 2013;Dong et al., 2017;Zhang et al., 2021), anther dehiscence, pollen maturation, induction of pollen germination (Kinoshita-Tsujimura and Kakimoto, 2011), and defects in the exine and Ubisch bodies (Aya et al., 2009). ...
Recalcitrant seeds are characterized by desiccation and freezing sensitivity, and short storage longevity. These physiological attributes obviate their ex situ conservation in conventional seed banks, where seeds are stored dry at sub-zero temperatures (typically, 15% relative humidity and-20 • C) for extended periods of time. Propagation of plants for field collections (e.g., botanical gardens, nurseries, and arboretums) is a valuable ex situ conservation option. However, these collections are relatively costly, require high maintenance, preserve limited genetic diversity and/or are directly exposed to biotic (e.g., pests) and abiotic (e.g., climatic) threats. Therefore, recalcitrant-seeded (RS) species are dependent on cryopreservation for their safe and long-term ex situ conservation. Different explant sources such as whole seeds, zygotic embryos, dormant buds, shoot tips, and pollen, can be used for plant propagation of RS species in field collections as well as for their cryopreservation. The success of the propagation or the cryopreservation of these explants often depends on their developmental status, vigor, and/or tolerance to desiccation and chilling/freezing. These attributes are modulated by the environment where the donor plant grows and we hypothesize that climate change, by affecting these biological attributes, would impact the success of explant propagation and cryopreservation. To support this hypothesis, we have reviewed how temperature changes and drought, the two main climate change scenarios, affect the main biological attributes that are directly involved in the success of ex situ conservation of tropical and temperate RS species. In general, increases in temperature and drought will negatively affect plant development in field collections and the quality of the explants used in cryopreservation. Consequently, field collections of RS species may need to be moved to more suitable places (e.g., higher latitudes/altitudes). Additionally, we may find a reduction in the success of cryopreservation of RS species germplasm directly harvested from field collections. However, we cannot always generalize these effects for all species since they often depend on the origin of the species (e.g., tropical and temperate species tend to respond to climate change differently), the genotype, the adaptive genetic potential of each population, and the severity of the environmental change. On the other hand, the increase in temperatures and water stress in donor plants at high-latitude areas and also some tropical environments may favor the production of seeds and seedlings better adapted to drying, and hence, increase the success of plant propagation and zygotic embryo cryopreservation.
... This includes reduced starch accumulation, which was observed in Optic pollen after heat stress at pollen mitosis. It has been suggested that stresses such as water stress can inhibit starch deposition in rice and wheat pollen, either by decreasing the availability of assimilates or by impairing the activities of enzymes involved in starch biosynthesis (Sheoran and Saini, 1996;Ji et al., 2010). Pressman et al. (2002) found that continuous high temperatures prevented the transient increase in starch concentration in tomato pollen grains which led to decreases in the concentrations of soluble sugars in the anther walls and the pollen. ...
The Poaceae, or grasses, include many agriculturally important cereal crops such as rice (Oryza sativa), maize (Zea mays), barley (Hordeum vulgare) and bread wheat (Triticum aestivum). Barley is a widely grown cereal crop used for stock feed, malting and brewing. Abiotic stresses, particularly global warming, are the major causes of crop yield losses by affecting fertility and seed set. However, effects of heat stress on reproductive structures and fertility in barley have not been extensively investigated. In this study we examined three commercial European spring barley varieties under high temperature conditions to investigate the effects on floret development. Using a combination of fertility assays, X-ray micro computed tomography, 3-dimensional modelling, cytology and immunolabelling, we observed that male reproductive organs are severely impacted by increased temperature, while the female reproductive organs are less susceptible. Importantly, the timing of stress relative to reproductive development had a significant impact on fertility in a cultivar-dependent manner, this was most significant at pollen mitosis stage with fertility ranged from 31.6-56.0% depending on cultivar. This work provides insight into how heat stress, when applied during male pollen mother cell meiosis and pollen mitosis, affects barley fertility and seed set, and also describes complementary invasive and non-invasive techniques to investigate floret development. This information will be used to identify and study barley cultivars that are less susceptible to heat stress at specific stages of floral development.
... Previous research has found that aberrant gene expression in anthers disrupts pollen formation and decrease pollen fertility. Changes in enzyme and carbohydrate activity expression could also reduce sugar and starch accumulation in the anthers [77]. Here, large numbers of DEGs in the KEGG pathways were enriched in metabolic pathways and starch and sucrose metabolism. ...
Background
Autotetraploid rice is a useful germplasm for the breeding of polyploid rice; however, low fertility is a major hindrance for its utilization. Neo-tetraploid rice with high fertility was developed from the crossing of different autotetraploid rice lines. Our previous research showed that the mutant ( ny1 ) of LOC_Os07g32406 ( NY1 ), which was generated by CRISPR/Cas9 knock-out in neo-tetraploid rice, showed low pollen fertility, low seed set, and defective chromosome behavior during meiosis. However, the molecular genetic mechanism underlying the fertility remains largely unknown.
Results
Here, cytological observations of the NY1 mutant ( ny1 ) indicated that ny1 exhibited abnormal tapetum and middle layer development. RNA-seq analysis displayed a total of 5606 differentially expressed genes (DEGs) in ny1 compared to wild type (H1) during meiosis, of which 2977 were up-regulated and 2629 were down-regulated. Among the down-regulated genes, 16 important genes associated with tapetal development were detected, including EAT1, CYP703A3, CYP704B2, DPW, PTC1, OsABCG26, OsAGO2, SAW1, OsPKS1, OsPKS2, and OsTKPR1 . The mutant of EAT1 was generated by CRISPR/Cas9 that showed abnormal tapetum and pollen wall formation, which was similar to ny1 . Moreover, 478 meiosis-related genes displayed down-regulation at same stage, including 9 important meiosis-related genes, such as OsREC8, OsSHOC1, SMC1, SMC6a and DCM1 , and their expression levels were validated by qRT-PCR.
Conclusions
Taken together, these results will aid in identifying the key genes associated with pollen fertility, which offered insights into the molecular mechanism underlying pollen development in tetraploid rice.
... The study confirmed that moisture stress during post flowering stage affected the yield potential of the sorghum landraces evaluated in the study area. This was in agreement with Sheoran, I.S. et al. [27] , who reported such yield reduction due to drought stress in wheat and rice. Blum, A. [28] also reported drought escape by shortening the life cycle of the crops at the expense of the yield potential of the crop in drought prone areas. ...
Sorghum is an important food crop in Eritrea where it is widely grown in the mid and low lands, of semi-arid regions. Eritrea being the center of origin of sorghum, a large variability exist in its landraces being grown by the farmers since generations. In order to improve the productivity of sorghum under moisture stress conditions, it is imperative to evaluate these landraces for drought tolerant characteristics and their use for further crop improvement programmes. Therefore, a field study was conducted in a randomized complete block design with three replications to estimate the extent of genetic variability of 20 sorghum genotypes for moisture stress tolerance using various morphological, phenological, yield and yield related parameters under rainfed conditions at Hagaz Research Station. Significant difference was observed for almost all the characters in the individual analysis of variance suggesting that these sorghum accessions were highly variable. Accessions EG 537, EG 1257, EG 849, EG 791, EG 783 and EG 813 showed promising results for post flowering drought tolerance, grain yield and stay green traits. Higher PCV and GCV were also obtained in parameters like plant height, leaf area, biomass, peduncle exertion, panicle length, and grain yield and panicle weight. The genotypes also exhibited varying degrees of heritability estimates. Characters such as plant height, panicle length, days to flowering and maturity showed higher heritability. Cluster analysis revealed that sorghum landraces were grouped on the basis of their morphological traits and geographical sites. 77.3% of the total variation of sorghum landraces was contributed by the first four principal components analysis having Eigen value > 1. Overall, the current study confirmed that EG 537, EG 849, EG 1257, EG 791, and EG 813 are drought tolerant sorghum landraces during post flowering stage.
