Search Results (222)

Water scarcity poses a substantial challenge for turfgrass irrigation in the drought- and heat-stressed Desert Southwest region of the United States. Bermudagrass (Cynodon spp.), renowned for its exceptional drought resistance, is the predominant warm-season turfgrass in the region. Selecting and using drought-resistant bermudagrass cultivars remains a primary strategy for sustaining the turfgrass industry in the region. This study evaluated 48 hybrid bermudagrasses (Cynodon dactylon × C. transvaalensis Burtt-Davy), including two commercial cultivars (‘TifTuf’ and ‘Tifway’, as controls), under 80% × ETo (0.8ET), 60% × ETo (0.6ET) and 40% × ETo (0.4ET) reference evapotranspiration (ETo) replacement irrigation systems at Maricopa, AZ. The experiment was laid out in a split-plot design with two replications, where the 3 irrigation treatments were assigned to main plots and 48 genotypes were in sub-plots. Analysis of data from two years (2022 and 2023) revealed significant differences among bermudagrass hybrids, irrigation treatments, and their interaction effects. The hybrids exhibited substantial variation for spring green-up, density, turf color, and quality. With the largest deficit irrigation treatment 40% × ETo (0.4ET), OSU2104, OSU2106, and OSU2105 showed greater mean greenness and aesthetic quality scores than recorded for ‘TifTuf’ (6.5), a popular drought-tolerant cultivar. The results highlight the prevalence of genetic variation in germplasm with potential for development of improved varieties for drought tolerance. Full article

As a key economic tree in southern China, Camellia oleifera faces severe yield losses under drought. Grafting onto drought-tolerant rootstocks offers a potential mitigation strategy. To elucidate the impact of rootstocks on the drought resistance of the superior Camellia oleifera Abel. cultivar “Xianglin 210”, grafted seedlings with five scion–rootstock combinations, were subjected to gradient drought stress. Key physiological and biochemical indices related to photosynthesis, antioxidant enzymes, and osmotic adjustment were measured. Drought resistance was comprehensively evaluated using membership function analysis, and the expression of stress-responsive genes was quantified via quantitative real-time PCR (qRT-PCR). The results demonstrated that under drought stress, (1) stomatal conductance (Gs) decreased by 31.2–48.7%, while instantaneous water use efficiency (WUE) increased by 18.5–35.4%; (2) proline (Pro) and soluble sugars (SS) accumulated significantly, with increases of 2.3–4.1-fold and 1.8–3.2-fold, respectively; (3) activities of antioxidant enzymes were enhanced by 56–127%, mitigating oxidative damage; (4) membership function analysis ranked drought resistance as follows: Xianglin 27 (0.812) > Guangxi Superior Germplasm (0.698) > C. yuhsienensis (0.654) > Hunan Superior Germplasm (0.591) > Xianglin 1 (0.523); (5) qRT-PCR revealed significant upregulation of ABA signaling pathway genes (CoPYL6, CoPP2C75/51/24/26, CoSnRK2.8, and CoABI5) and transcription factors (CoLHY and CoWRKY70), indicating activation of drought-responsive regulatory networks. These findings provide a theoretical foundation for selecting drought-tolerant rootstocks and optimizing cultivation practices in Camellia oleifera, and provide practical criteria for selecting drought-tolerant rootstocks, facilitating sustainable Camellia oleifera cultivation in water-limited regions. Full article

Improving yield stability under water-limited conditions is a key objective of wheat breeding programmes. One trait of particular interest is carbohydrate accumulation and remobilisation. This study assessed the genetic basis of aspects of yield and flag leaf sugar contents under drought and well-watered conditions using QTL mapping in a population of 90 doubled haploid lines derived from the cross Chinese Spring × SQ1. As well as soluble sugar content, glucose, fructose, sucrose, and maltose, the traits grain yield (Yld), biomass (Bio), and thousand grain weight (TGW) were also analysed. Analysis of variance showed that genotype, environment and their interactions significantly influenced all the traits studied, with environmental effects explaining up to 74.4% of the total variation. QTL analysis identified 40 QTLs for Yld, TGW, and Bio as well as 53 QTLs for soluble carbohydrates, accounting for up to 40% of phenotypic variation. QTLs coincident for more than one trait were identified on 21 chromosome regions, associated with carbohydrate metabolism and yield performance under drought, particularly on chromosomes 2D, 4A, 4B, 5B, 5D, 6B, and 7A. Candidate genes for several yield-related QTLs were identified. These results provide useful genetic markers for the development of more drought-resistant wheat cultivars. Full article

Camellia oleifera, a woody oilseed species endemic to China, often experiences growth constraints due to seasonal drought. This study investigates the coordinated regulation of photosynthetic traits, stomatal behavior, and hormone responses during drought–rehydration cycles in two cultivars with contrasting drought resistance: ‘CL53’ (tolerant) and ‘CL40’ (sensitive). Photosynthetic inhibition resulted from both stomatal and non-stomatal limitations, with cultivar-specific differences. After 28 days of drought, the net photosynthetic rate (P_n) declined by 26.6% in CL53 and 32.6% in CL40. A stable intercellular CO₂ concentration (C_i) in CL53 indicated superior mesophyll integrity and antioxidant capacity. CL53 showed rapid P_n recovery and photosynthetic compensation post-rehydration, in contrast to CL40. Drought triggered extensive stomatal closure; >98% reopened upon rehydration, though the total stomatal pore area remained reduced. Abscisic acid (ABA) accumulation was greater in CL40, contributing to stomatal closure and P_n suppression. CL53 exhibited faster ABA degradation and gibberellin (GA₃) recovery, promoting photosynthetic restoration. ABA negatively correlated with P_n, transpiration rate (T_r), stomatal conductance (G_s), and C_i, but positively with stomatal limitation (L_s). Water use efficiency (WUE) displayed a parabolic response to ABA, differing by cultivar. This integrative analysis highlights a coordinated photosynthesis–stomata–hormone network underlying drought adaptation and informs selection strategies for drought-resilient cultivars and precision irrigation. Full article

Soil salinization poses a significant threat to tea plant (Camellia sinensis) production by compromising its bioactive compounds, such as polyphenols, L-theanine, and caffeine, which are key contributors to the plant’s health benefits and economic value. This study investigates the Salt Overly Sensitive 1 (SOS1) gene family, a critical salt-tolerance regulator in tea plants, to elucidate its role in maintaining quality under environmental stress. Genome-wide analysis identified 51 CsSOS1 genes, with phylogenetic and synteny analyses revealing strong evolutionary conservation with Populus trichocarpa and Arabidopsis thaliana. Promoter analysis detected stress- and hormone-responsive cis-elements, indicating adaptive functions in abiotic stress. Expression profiling demonstrated tissue-specific patterns, highlighting significant upregulation of CsSOS1-15 and CsSOS1-41 under salt and drought stress. Co-expression network analysis further linked CsSOS1 genes to carbohydrate metabolism, implicating their roles in stress resilience and secondary metabolite synthesis. Our findings provide molecular insights into CsSOS1-mediated salt tolerance, proposing potential targets for preserving bioactive compounds. This work facilitates developing salt-resistant tea plant cultivars to ensure sustainable production and quality stability amid environmental challenges. Full article

Climate change can severely impact plant-pollinator interactions and have serious effects on ecosystem services such as pollination. This study was carried out in 2023 and 2024, and it examined the effects of drought on flowering and nectar production in one cultivar of white mustard (Brassica alba cv. Palma), an important entomophilous crop of the temperate zone with several attributes that make it promising for sustainable agricultural practices. Drought-stressed plants delayed the flowering time, shortened the flowering duration, and developed significantly fewer flowers. Nectar production in white mustard depends on soil moisture levels and short-term changes in meteorological conditions (e.g., air humidity, air temperature). At reduced soil moisture, the total sugar yield per plant decreased by 60%, compared to control plants, resulting in lower availability of caloric food resources, which should be considered when developing strategies supporting pollinators. Changes in floral traits resulted in differences in the frequency of insect visits, which may exert a negative impact on white mustard pollination under drought stress and may have indirect consequences for seed yield resulting from increased drought intensity associated with climate change. The results provide important data for the management of the white mustard crop and indicate the need for broader evaluation of cultivars to promote drought-resistant B. alba cultivars. Full article

The plant cuticle, a protective barrier against external stresses, and abscisic acid (ABA), a key phytohormone, are crucial for plant growth and stress responses. Heterologous expression of AtNCED3 in plants has been widely studied. In this research, by comparing the japonica rice cultivar Zhonghua 10 and its AtNCED3 over-expressing lines during the vegetative growth stage through multiple methods, we found that AtNCED3 over-expression increased leaf ABA content, enhanced epidermal wax and cutin accumulation, modified wax crystal density, and thickened the cuticle. These changes reduced leaf epidermal permeability and the transpiration rate, thus enhancing drought tolerance. This study helps understand the role of endogenous ABA in rice cuticle synthesis and its mechanism in plant drought tolerance, offering potential for genetic improvement of drought resistance in crops. Full article

Chickpea is a legume that grows in most parts of the world. It is negatively affected by abiotic and biotic factors like drought and fungal diseases, respectively. One of the most important soil-borne pathogens affecting chickpeas is Fusarium oxysporum f.sp. ciceris (Foc). Its population dynamics in the soil are affected by fluctuations in soil water content and host characteristics. For the last three decades, drought has been common in most areas of the world due to global warming. Drought stress decreases the quality and quantity of the chickpeas, particularly where soil-borne pathogens are the main stress factor for plants. The use of both drought-tolerant and disease-resistant cultivars may be the only option for cost-effective yield production. In this study, we screened the seeds of twelve chickpea genotypes WR-315, JG-62, C-104, JG-74, CPS-1, BG-212, ANNIGERI, CHAFFA, BG-215, UC-27, ILC-82, and K-850 for drought tolerance at increasing polyethylene glycol (PEG) concentrations (0-, 5-, 7.5-, 10-, 15-, 20-, 25-, 30- and 50%) to create drought stress conditions at different severities. The performances of genotypes that were previously tested in Foc resistance/susceptibility studies were assessed in terms of percentage of germination, radicle and hypocotyl length, germination energy, germination rate index, mean germination time, and vigor index in drought conditions. We determined the genotypes of C-104, CPS-1, and WR-315 as drought-susceptible, moderately drought-tolerant, and drought-tolerant, respectively. We then elucidated the stress levels of selected genotypes (20-day-old seedlings) at 0–15% PEG conditions via measuring proline and malondialdehyde (MDA) contents. Our findings showed that genotypes that were resistant to Foc also exhibited drought tolerance. The responses of chickpea genotypes infected with Foc under drought conditions are the next step to assess the combined stress on chickpea genotypes. Full article

Olive trees are generally considered a species well-adapted to drought, but the impact of water shortage is of critical importance on olive production. For this reason, developing tolerant cultivars could be an effective strategy to mitigate the impact of drought in the future. Characterizing drought stress tolerance in olive is a complex task due to the numerous traits involved in this response. In this study, plant growth, pressure–volume curves, gas-exchange and chlorophyll fluorescence traits, and stomata characteristics were monitored in nine cultivars to assess the effects of mild and severe drought stress conditions induced by withholding water for 7 and 21 days, respectively, and were compared to a well-watered control treatment. The plant materials evaluated included traditional cultivars, as well as new developed cultivars suited for high-density hedgerow olive orchards or resistant to verticillium wilt. Significant differences between cultivars were observed for most evaluated traits, with more pronounced differences under severe drought conditions. A multivariate analysis of the complete dataset recorded throughout the evaluation period allowed for the identification of promising cultivars under stress conditions (‘Sikitita’, ‘Sikitita-2’, and ‘Martina’) as well as highly discriminative traits that could serve as key selection parameters in future breeding programs. Full article

LncRNAs, a type of RNAs exceeding 200 nucleotides (nt) and lacking representative open reading frames (ORFs), have emerged as crucial regulatory molecules that modulate numerous growth and development processes in plants. While substantial progress has been made in interpreting the functions and regulatory mechanisms of coding RNAs, the study of lncRNAs in Tibetan hulless barley remains incomplete. To elucidate the coordination of drought stress responses in Tibetan hulless barely by lncRNAs, we analyzed the previously published RNA-seq data from two cultivars of hulless barley, drought-tolerant (Z772) and drought-sensitive (Z013), subjected to varying durations of drought treatment (0, 1, and 5 h). Initially, we identified a total of 2877 lncRNAs through a strict pipeline, of which 2179 were co-expressed in both cultivars. Additionally, 331 and 367 lncRNAs showed cultivar-specific expression patterns in Z772 and Z013, respectively. Given the trans-regulatory functions of lncRNAs, we utilized WGCNA and uncovered 11 modules that were enriched in drought-responsive pathways. Within these modules, lncRNAs and neighboring PCGs were co-clustered in key control modules. The GO enrichment analysis of potential lncRNA-PCG pairs primarily involved processes related to the response to water deprivation, regulation of abiotic stress, and RNA metabolic processes. Notably, 12 high-confidence lncRNA-PCG pairs displayed concordant expression profiles, with some annotated as TFs. Two of these pairs were validated by qRT-PCR in the Tibetan hulless barley cultivar Kunlun 14. These findings suggested that lncRNAs may participate in regulatory networks involved in drought adaptation in Tibetan hulless barley, offering novel insights into the drought resistance mechanisms of Poaceae crops and potential targets for breeding drought-resistant varieties. Full article

Drought is a major factor limiting crop growth and yield. Enhancing drought resistance is an important strategy to sustain higher yields, with an emphasis on developing drought-tolerant cultivars. In this study, 19 sorghum varieties from both domestic and international sources were selected as experimental materials. At the seedling stage, 11 above-ground and below-ground phenotypic traits were investigated. Under 25% PEG-6000 concentration, drought tolerance during the seedling stage was assessed using differential analysis, such as correlation analysis, principal component analysis (PCA), membership function analysis, regression analysis, and cluster analysis. The present results demonstrate that the principal component analysis could represent 77.18% of the data from the original 11 indicators. Total root length, stem diameter, and leaf area were identified as the main evaluation indicators for sorghum seedling drought tolerance. In addition, based on principal component scores (F) and drought tolerance metric values (D), the 19 sorghum varieties were classified into three categories through systematic cluster analysis: two varieties were classified as highly drought-tolerant, nine as moderately drought-tolerant, and eight as drought-sensitive. Two varieties, such as Longza 24 and Jinza 12, were identified as drought-tolerant during the seedling stage and can serve as valuable resources for evaluating drought tolerance throughout the full growth period and for breeding improvements. Hence, this study established a drought tolerance evaluation method by integrating above- and below-ground phenotypic traits indicators, providing theoretical support for the identification of drought-tolerant sorghum. Full article

Forage scarcity, intensified by climate variability and edaphoclimatic limitations in the Brazilian semiarid region, challenges regional livestock production. In this context, forage palm is a strategic alternative due to its drought resistance and environmental adaptability. However, little is known about the spatial and temporal dynamics of its cultivation. This study aimed to characterize the spatio-temporal dynamics of forage palm cultivation in Capoeiras-PE between 2019 and 2022 using remote sensing data and multitemporal analysis of the Normalized Difference Vegetation Index (NDVI), processed via Google Earth Engine. Experimental areas with Opuntia stricta (“Mexican Elephant Ear”) and Nopalea cochenillifera (“Miúda”) were monitored, with field validation and descriptive statistical analysis. NDVI values ranged from −0.27 to 0.93, influenced by rainfall, cultivar morphology, and seasonal conditions. The “Miúda” cultivar showed a lower coefficient of variation (CV%), indicating greater spectral stability, while “Orelha de Elefante Mexicana” was more sensitive to climate and management, showing a higher CV%. Land use and land cover (LULC) analysis indicated increased sparse vegetation and exposed soil, suggesting intensified anthropogenic activity in the Caatinga biome. Reclassified NDVI enabled spatial estimation of forage palm, despite sensor resolution and spectral similarity with other vegetation. The integrated use of satellite data, field validation, and geoprocessing tools proved effective for agricultural monitoring and territorial planning. Full article

Maize (Zea mays L.) is a staple cereal crop worldwide, but its productivity is significantly affected by extreme weather conditions such as drought and heat stress. Plant growth, physiological processes, and yield potential are all affected by these conditions; as such, resilient maize crops are required to tackle these abiotic challenges. With an emphasis on morphological, physiological, and biochemical reactions, this review paper investigates the processes that underlie resistance to certain environmental challenges. Features including deep root systems, osmotic adaptations, and antioxidant enzyme activity help maize withstand drought. Activation of drought- and heat-responsive genes, accumulation of osmoregulatory compounds, and changes in membrane fluidity are all components of abiotic stress tolerance. Likewise, improved transpiration efficiency, modified photosynthetic processes, and improved heat shock proteins are used to produce heat resistance. Enhancing resilience requires progress in breeding methods, genetic engineering, and agronomic techniques, such as the use of stress-tolerant cultivars, biotechnology interventions, and climate-smart agriculture tactics. A special focus was given to cutting edge technologies like CRISPER-Cas9-mediated recent advances in heat and drought resistance. This review sheds light on recent studies and potential avenues for enhancing resilience to harsh climatic conditions, guaranteeing food security in the face of climate change. Full article

Plant cuticles are crucial for protecting plants from various environmental stresses. Seed priming with abscisic acid (ABA) enhances crop stress tolerance, but its molecular mechanisms in cuticular wax and cutin biosynthesis remain unclear. This study investigated ABA-priming’s role in boosting cuticular wax and cutin accumulation in sweet sorghum (Sorghum bicolor L.) using physiological and transcriptomic analyses. Abscisic acid priming increased leaf wax (37.7%) and cutin (25.6%) under drought, reducing water loss (9.8–36.6%) and improving leaf water content (28.4–120%). Transcriptomics identified 921 differentially expressed genes, including key fatty acid biosynthesis genes (ADH2, DES2, KAS2). Co-expression analysis revealed the synergistic regulation of wax and cutin biosynthesis by the abscisic acid and jasmonic acid (JA) pathways. Exogenous ABA and JA application confirmed their roles, with combined treatment increasing wax content by 71.7% under drought stress. These findings were validated in other sweet sorghum cultivars (DLS and ML8000), highlighting the potential of ABA priming as a universal strategy to enhance wax deposition in crops. Our study provides new insights into the molecular mechanisms underlying ABA-induced drought resistance and offers a practical approach for improving crop resilience in water-limited environments. Full article

Rhododendron L., a renowned ornamental species and one of the ten famous flowers in China, is highly regarded for its aesthetic value and extensive applications in landscaping. However, its growth and quality are significantly compromised by drought stress, particularly in regions with dry conditions. To elucidate the drought response mechanisms of Rhododendron, two cultivars, ‘SaKeSiZhiXing’ (SKSZX) and ‘TuRuiMeiGui’ (TRMG), were subjected to natural drought stress, and changes in chlorophyll fluorescence and transcriptomic profiles were examined at 0 days (d), 4 d, and 8 d of drought exposure. An OJIP fluorescence transient (O-J-I-P) analysis revealed a progressive decline in the F_P parameter and an increase in the F_J parameter as drought stress intensified. Additionally, a delayed fluorescence (DF) analysis showed a gradual reduction in the I₁ and I₂ values within the induction and decay curves under prolonged drought conditions. The 820 nm curve indicated the deactivation of a transient phase characterized by a rapid decline, followed by a slow recovery in the modulated reflection (MR) signal. A transcriptomic analysis of leaves identified 24,352, 18,688, and 32,261 differentially expressed genes (DEGs) in SKSZX at 0 d, 4 d, and 8 d of drought treatment, respectively. In contrast, TRMG exhibited more pronounced and earlier drought-induced alterations. These DEGs were primarily enriched in pathways related to phenylpropanoid biosynthesis, plant hormone signaling, photosynthesis, and photosynthesis-antenna proteins. Additionally, 565 transcription factors (TFs) were identified, including bHLH, WRKY, bZIP, MYB-related, MYB, C2H2, and HSF families. The drought-induced changes in TRMG were more substantial and occurred earlier compared to SKSZX, with a greater impairment in the electron transfer capacity at both the donor and acceptor sides of photosystem II (PSII). This study provides valuable insights into the molecular mechanisms underlying drought tolerance in Rhododendron and offers a foundation for molecular breeding strategies aimed at enhancing drought resistance in future cultivars. Full article