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Under climate change, extreme droughts will limit water availability for plants. However, the species-specific responses make it difficult to draw general conclusions. We hypothesized that changes in species’ abundance in response to extreme drought can be best explained by a set of water economic traits under ambient conditions in combination with the ability to adjust these traits towards higher drought resistance. We conducted a 4-year field experiment in temperate grasslands using rainout shelters with 30% and 50% rainfall reduction. We quantified the response as the change in species abundance between ambient conditions and the rainfall reduction. Abundance response to extreme drought was best explained by a combination of traits in ambient conditions and their functional adjustment, most likely reflecting plasticity. Smaller leaved species decreased less in abundance under drought. With increasing drought intensity, we observed a shift from drought tolerance, i.e., an increase in leaf dry matter content, to avoidance, i.e., a less negative turgor loss point (TLP) in ambient conditions and a constancy in TLP under drought. We stress the importance of using a multidimensional approach of variation in multiple traits and the importance of considering a range of drought intensities to improve predictions of species’ response to climate change.

Tree species adopt diverse drought resistance strategies, which are crucial for the ability of karst vegetation to adapt to drought stress. However, our understanding of how to differentiate these strategies remains limited, particularly with respect to identifying indicator traits that can accurately distinguish the drought resistance strategies used by different species. In this study, we use principal component analysis based on functional traits to distinguish the drought resistance strategies of Platycladus orientalis and Broussonetia papyrifera ; we identify key indicator traits reflecting differences in drought resistance strategies by analyzing the correlations of the same traits across different plant species. Most importantly, in this study, stomatal transpiration efficiency is proposed as a novel trait. Principal component analysis based on functional traits can distinguish plant drought resistance strategies. A correlation analysis of the indicators revealed that 2,2-diphenyl-picrylhydrazyl radical-scavenging activity, Δcrown width, stomatal transpiration efficiency, and water use efficiency can serve as critical markers to differentiate the drought resistance strategies of plants. Notably, the stomatal transpiration efficiency of P. orientalis and B. papyrifera exhibited entirely opposite trends under drought stress ( r = -0.38); however, investigations of additional tree species are needed to further verify the reliability of stomatal transpiration efficiency as an indicator of different plant drought resistance strategies. These findings improve our ability to effectively differentiate karst plant drought resistance strategies and understand the mechanisms involved.

Phenotypic plasticity is one of the main mechanisms of adaptation to abiotic stresses via changes in critical developmental stages. Altering flowering phenology is a key evolutionary strategy of plant adaptation to abiotic stresses, to achieve the maximum possible reproduction. The current study is the first to apply the linear regression residuals as drought plasticity scores while considering the variation in flowering phenology and traits under non-stress conditions. We characterized the genomic architecture of 17 complex traits and their drought plasticity scores for quantitative trait loci (QTL) mapping, using a mapping population derived from a cross between durum wheat (Triticum turgidum ssp. durum) and wild emmer wheat (T. turgidum ssp. dicoccoides). We identified 79 QTLs affected observed traits and their plasticity scores, of which 33 reflected plasticity in response to water stress and exhibited epistatic interactions and/or pleiotropy between the observed and plasticity traits. Vrn-B3 (TaTF1) residing within an interval of a major drought-escape QTL was proposed as a candidate gene. The favorable alleles for most of the plasticity QTLs were contributed by wild emmer wheat, demonstrating its high potential for wheat improvement. Our study presents a new approach for the quantification of plant adaptation to various stresses and provides new insights into the genetic basis of wheat complex traits under water-deficit stress.

This paper illustrated the drought resistance strategy, analyzed the profile, characteristics, development tendency and the cause of the drought in Guizhou Province. And the paper analyzed the major measures and achievements of the drought resistance emphatically to provide a reference basis for Guizhou drought resistance.

Several studies conducted under high input conditions have indicated little susceptibility of pearl millet to water deficit untill early grain filling, because the losses in main shoot production were fully compensated by increased tiller fertility. The present study assessed the impact of water deficits at three development stages: prior to flowering (S30), at the beginning of flowering (S45), and at the end of flowering (S60) in pearl millet grown in experimental conditions similar to Sahelian farming conditions. It included a control irrigation treatment simulating the natural distribution of rainfall throughout the cropping season. Both biomass production and grain yield were severely reduced by S30 and S45, while S60 had no effect. In S30 and S45, the flowering of tillers was delayed or totally inhibited. In both of these treatments, the low number of productive tillers did not compensate for damage to panicle initiation and flowering of the main shoot. All treatments maintained green leaves on the main shoot during the grain filling period, and in S30 leaf growth recovered from mid-season drought. These results illustrate how pearl millet mostly escapes drought by matching its phenology to the mean rainfall distribution in the Sahel. In the case of mid-season drought, some late productive tillers and the maintenance of green leaf biomass of the main shoots limited, but did not overcome, the yield losses. This study stresses the importance of agro-ecological conditions in control treatments, particularly the water regime and crop density, when assessing crop drought resistance.

Summary The growth and yield of many crops, including cotton, are affected by water deficit. Cotton has evolved drought specific as well as general morpho‐physiological, biochemical and molecular responses to drought stress, which are discussed in this review. The key physiological responses against drought stress in cotton, including stomata closing, root development, cellular adaptations, photosynthesis, abscisic acid (ABA) and jasmonic acid (JA) production and reactive oxygen species (ROS) scavenging, have been identified by researchers. Drought stress induces the expression of stress‐related transcription factors and genes, such as ROS scavenging, ABA or mitogen‐activated protein kinases (MAPK) signalling genes, which activate various drought‐related pathways to induce tolerance in the plant. It is crucial to elucidate and induce drought‐tolerant traits via quantitative trait loci (QTL) analysis, transgenic approaches and exogenous application of substances. The current review article highlights the natural as well as engineered drought tolerance strategies in cotton.

The iso/anisohydric continuum describes how plants regulate leaf water potential and is commonly used to classify species drought response strategies. However, drought response strategies comprise more than just this continuum, incorporating a suite of stomatal and hydraulic traits. Using a common garden experiment, we compared and contrasted four metrics commonly used to describe water use strategy during drought in 10 eucalyptus species comprising four major ecosystems in eastern Australia. We examined the degree to which these metrics were aligned with key stomatal and hydraulic traits related to plant water use and drought tolerance. Species rankings of water use strategy were inconsistent across four metrics. A newer metric (Hydroscape) was strongly linked to various plant traits, including the leaf turgor loss (TLP), water potential at stomatal closure (Pgs90), leaf and stem hydraulic vulnerability to embolism (PL50 and Px50), safety margin of hydraulic segmentation (HSMHS), maximum stomatal conductance (gsmax) and Huber value (HV). In addition, Hydroscape was correlated with climatic variables representing the water availability at the seed source site. Along the continuum of water regulation strategy, species with narrow Hydroscapes tended to occupy mesic regions and exhibit high TLP, PL50 and Px50 values and narrow HSMHS. High gsmax recorded in species with broad hydroscapes was also associated with high HV. Despite a fourfold difference in Hydroscape area, all species closed their stomata prior to the onset of hydraulic dysfunction, suggesting a common stomatal response across species that minimizes embolism risk during drought. Hydroscape area is useful in bridging stomatal regulation, hydraulic architecture and species drought tolerance, thus providing insight into species water use strategies. A plain language summary is available for this article. Plain Language Summary

Drought stress is one of the most important abiotic stresses which causes many yield losses every year. This paper presents a comprehensive review of recent advances in international drought research. First, the main types of drought stress and the commonly used drought stress methods in the current experiment were introduced, and the advantages and disadvantages of each method were evaluated. Second, the response of plants to drought stress was reviewed from the aspects of morphology, physiology, biochemistry and molecular progression. Then, the potential methods to improve drought resistance and recent emerging technologies were introduced. Finally, the current research dilemma and future development direction were summarized. In summary, this review provides insights into drought stress research from different perspectives and provides a theoretical reference for scholars engaged in and about to engage in drought research.

Identifying key traits that can serve as proxies for species drought resistance is crucial for predicting and mitigating the effects of climate change in diverse plant communities. Turgor loss point (πtlp) is a recently emerged trait that has been linked to species distributions across gradients of water availability. However, a direct relationship between πtlp and species ability to survive drought has yet to be established for woody species. Using a manipulative field experiment to quantify species drought resistance (i.e., their survival response to drought), combined with measurements of πtlp for 16 tree species, we show a negative relationship between πtlp and seedling drought resistance. Using longterm forest plot data, we also show that πtlp predicts seedling survival responses to a severe El Niño-related drought, although additional factors are clearly also important. Our study demonstrates that species with lower πtlp exhibit higher survival under both experimental and natural drought. These results provide a missing cornerstone in the assessment of the traits underlying drought resistance in woody species and strengthen πtlp as a proxy for evaluating which species will lose or win under projections of exacerbating drought regimes.

Climate change is one of the multiple challenges facing all categories of farmers globally. However, African farmers are the most sensitive in respect of climate variability and change. Climate change impacted negatively on crop production and the livelihoods of the local farmers. In black township South Africa, agricultural activities are highly dominated by small-scale farmers, whose farming system is highly vulnerable to changes in climate. This paper presents the analysis of how small-scale farmers employed adaptation strategies in response to climate change and determinants of small-scale households’ choices of coping and adaptation approach to climate variability and change in Vhembe District, South Africa. Multi nominal logit model was used on a surveyed of 224 local farmers. Farmers’ socio-economic attributes, was used in response to climate changes and further, households have adaptation strategies both on-farm and off-farm approach. Such approaches were; drought-tolerant seeds, shorter cycle crops, diversification of crops, changing planting dates, small-scale irrigation, migrating to urban areas and involvement in petty business. The results of the findings reveals that the significant drivers affecting choice of adaptation approach include climate information, gender, farm size, education level, farmer experience, decreasing rainfall and increases in temperature as farmers’ determinant choices of adaptation to climate change. While, on the other hand, off-farm resources, headed households and age had no significant impact on the choice of coping and adaptation approach to climate change. Therefore, policy makers in the local municipality should play a significant role by enhancing adaptation strategies appropriate for particular climatic shock on the study area.