ABSTRACT Although exogenous salicylic acid (SA) has the potential to assist sweet potatoes in coping with drought stress (DS), the specific effects on leaf antioxidant metabolism and storage root yield during the bulking stage remain poorly understood. To investigate this, a pond experiment was conducted in 2024 and 2025 to assess the influences of SA on leaf oxidative damage, antioxidant systems, and final yield under DS. Results demonstrated that DS significantly elevated peroxidase, superoxide dismutase, and catalase activities in leaves. However, this increase was insufficient to regulate reactive oxygen species (ROS) levels, leading to a marked hydrogen peroxide and superoxide anion accumulation, which subsequently induced oxidative stress. Consequently, this oxidative stress significantly increased malondialdehyde (MDA) content while reducing leaf relative water content (LRWC), ultimately leading to a decrease in storage root yield by 49.26% to 55.47%. Notably, exogenous SA application reduced the total leaf antioxidant capacity and decreased peroxidase (POD), superoxide dismutase (SOD), and catalase (CAT) activities. Concurrently, SA treatment improved LRWC, restored chloroplast ultrastructure, and reduced abscisic acid (ABA) accumulation, thereby effectively alleviating the build‐up of ROS and MDA. Further analysis indicated that SA decreased ascorbate content and ascorbate peroxidase activity, while simultaneously increasing glutathione content and glutathione peroxidase (GPX) expression within the ascorbate–glutathione cycle. This indicates a strategic reallocation of resources towards the GSH‐GPX branch. Such an approach facilitated effective ROS scavenging at a reduced metabolic cost, thereby sustaining leaf photosynthetic capacity and enhancing final yield by 53.18% to 68.02% relative to DS alone. In conclusion, exogenous SA enhances drought tolerance in sweet potatoes not merely by elevating total antioxidant capacity, but by improving antioxidant efficiency through the restoration of leaf water status and chloroplast integrity, attenuation of ABA signalling, and resource reallocation within the AsA‐GSH cycle.
ABSTRACT Deterioration in the appearance quality of brown rice due to heat‐stress‐induced ripening damage is a severe agricultural problem exacerbated by global warming. Five rice ( Oryza sativa L.) cultivars differing in their tolerance to heat‐stress‐induced ripening (‘Fukei 227,’ ‘Fusaotome,’ ‘Komanomai,’ ‘Sasanishiki,’ and ‘Hatsuboshi’) were used to measure the water potential and aquaporin‐related gene expression in flag leaves and panicles at heading to examine their correlations with brown rice appearance traits at harvest. Post‐heading mean air temperatures exceeded 26°C for all cultivars, confirming ripening under heat‐stress conditions. In heat‐stress‐tolerant cultivars, higher water potentials of flag leaves and elevated OsPIP2;2 and OsTIP1;2 expression levels were associated with lower milky‐white and immature grain percentages. In panicles, lower water potentials combined with the suppressed expression of OsPIP2;1 , OsPIP2;2 , OsPIP2;4 , and OsNIP2;1 genes and the upregulated expression of OsTIP2;1 , OsTIP2;2 , and OsTIP4;2 genes were associated with lower percentages of all grain categories with poor appearance quality. These results indicate that in heat‐stress‐tolerant cultivars, a coordinated organ‐specific water‐control strategy operates at heading. The aquaporin‐mediated increase in water transport maintains source function in flag leaves, whereas the suppression of the plasma‐membrane‐specific aquaporin genes and the upregulation of the tonoplast‐specific aquaporin genes stabilize sink function in panicles, collectively preserving brown rice appearance quality. ‘Hatsuboshi’ maintained a high appearance quality through a distinct mechanism independent of these water‐related physiological traits.
ABSTRACT Understanding genotype × environment (G × E) interactions is essential for improving yield stability and resource use efficiency in sugar beet ( Beta vulgaris L.) under variable water availability. Field experiments with six diverse genotypes grown under two contrasting water regimes (fully irrigated vs. rain‐excluded) across two seasons were used to derive genotype‐specific parameter sets for storage root partitioning ( RP max , k DM ), within‐leaf partitioning ( flb , fla ), specific leaf blade area ( a SLA ) and rooting depth dynamics ( k zb ). Storage root partitioning was best described by a rectangular hyperbola: Maximum storage root proportion ( RP max ) differed significantly among genotypes and between water regimes, whereas dry matter at half maximum ( k DM ) showed no significant variation. Specific leaf blade area declined under reduced water availability and exhibited strong genotypic control. Partitioning between leaf blades and petioles varied with increasing leaf dry matter among genotypes in both intercept and slope but was not affected by water regime. Rooting dynamics were captured by an expo‐linear function with a transition to linear growth at approximately 288°Cd; genotypes differed in linear‐phase rooting speed (G4 ≈ G1 > G5 > G6 > G2 > G3). No statistically significant genotype × water regime interaction was detected for any estimated parameter, suggesting that genotype‐specific baseline parameters can be retained and, within the range of conditions tested, dynamically scaled by a common continuous water‐status modifier (ratio of actual to potential transpiration, T act T pot −1 ).
ABSTRACT Heat stress at reproductive stage is a significant concern across wheat‐producing countries and affecting its annual production. This review is focusing on the adoption of management techniques, that is, crop and environmental modelling using advanced statistical tools to reduce the adverse effects of flowering‐stage heat stress. Further, we aim to provide insights into the morpho‐physiological and molecular impacts, tolerance mechanisms, and adaptation strategies to combat heat stress in wheat. Our work indicates that predictive models can integrate variables such as temperature, radiation, and precipitation with crop physiological responses, but require multi‐year and multilocation data. Likewise, we included the studies for marker‐trait associations, linkage diequilibrium‐based haplotypes and selective sweeps, to cope heat stress at this stage but again, the reported information require further validation through gene editing tools. Further, this comprehensive review indicates that a systematic combination of approaches, that is, modelling of climate, physiological breeding, and advanced tools can be helpful to develop heat‐resilient wheat genotype.
While shallow groundwater can buffer rainfed crops against drought, its usefulness depends critically on water quality, as groundwater salinity can limit this contribution. In the Chaco-Pampas plain, widespread shallow water tables are increasingly regarded as a water source by farmers, yet field-based evidence on how groundwater salinity affects crop performance under real production conditions remains limited. Most of the existing knowledge comes from controlled experiments using 'top-down' saline irrigation, which do not adequately represent the 'bottom-up' capillary contribution of saline groundwater typical of rainfed field settings. Understanding these responses and their interaction with rainfall variability is essential to guide adaptive management in these agroecosystems. We took advantage of a natural gradient of groundwater salinity (approximate to 2-11 dS m(-1)) with uniformly shallow depths (< 2 m) under real field conditions in the western Pampas (temperate sub-humid climate, coarse-textured soils) to evaluate its effects on rainfed soybean, maize, and wheat. Manual yield sampling and yield-component analysis (grain number m(-2), thousand-grain weight) were complemented with ecophysiological measurements (leaf temperature and stomatal conductance) and time series of the fraction of absorbed photosynthetically active radiation (fAPAR) derived from Sentinel-2 NDVI. Relative yields were modelled using a curvilinear, exponential-type function to estimate the salinity level causing a 50% yield reduction (C-50) and the Salinity Tolerance Index (ST-index). Groundwater salinity significantly reduced the yields of the three crops, following a clear tolerance ranking: wheat (C-50 = 8.4 dS m(-1)) > maize (C-50 = 5.0 dS m(-1)) > soybean (average C-50 = 4.8 dS m(-1)). Observations in multiple growing seasons for soybean revealed some inter-annual variability, with tolerance (C-50) tending to increase under wetter conditions (R-2 = 0.98, n = 4, p = 0.009). Yield reductions were primarily associated with decreases in grain number (56%-98% variability explanation), while grain weight was mainly affected in maize and in soybean during dry seasons (36%-43% variability explanation). Higher groundwater salinity also impaired plant water status (lower stomatal conductance, higher leaf temperature) and reduced fAPAR, more markedly in maize and soybean under dry conditions. Crop response thresholds to groundwater salinity should not be regarded as a fixed physiological attribute but rather as a dynamic ecohydrological property modulated by rainfall inputs. Depending on its salinity and the prevailing climatic conditions, shallow groundwater can act either as a resource or as a stress factor for crops. These findings highlight the need for adaptive management strategies that integrate groundwater salinity monitoring with seasonal climate forecasts, enabling risk zoning and the prioritization of more tolerant crops (such as wheat) in high-risk areas or years.
Soybean breeding faces the ongoing challenge of developing genotypes that combine high yield performance, nutritional and grain quality, with phenotypic stability and adaptation to different environmental conditions. The objective of this study was to investigate genetic variability, genotype & times; environment interaction and phenotypic stability to ensure the relationship among nutritional, agronomic and industrial traits in soybean for the selection of superior parents and genotypes. Thirty-six genotypes, including 28 F2 genotypes and eight parental lines, were evaluated in two environments. Nutritional traits (P, K, Ca, Mg, S, Mn, Zn, Cu, Fe), agronomic traits (days to maturity, plant height, grain yield) and industrial traits (protein, oil, fibre, ash content) were analysed. Variance analyses indicated genetic variability and genotype & times; environment interaction for most traits. The first two canonical variables (45.9%) showed that genotype P16 was associated with oil content, while genotypes P20, P21 and G4 were related to Fe, K, Zn, protein content and grain yield. Genotypes P1, G2 and G6 were associated with Mg content and days to maturity, whereas genotype P23 was linked to Cu, fibre and Ca content. Adaptability and stability were estimated using the Lin and Binns index and the multivariate P im index. The multivariate index combined with the GT-biplot explained 77.5% of the total results. Three genotypes were selected: P20 exhibited good averages and stability for the group of nutritional and agronomic traits, while P2 and P4 were indicated for the group of industrial traits. These three genotypes can be developed and utilized in breeding blocks for multiple traits, meeting the demands of producers, industry and consumers.
ABSTRACT Rising temperatures driven by climate change threaten global maize ( Zea mays L.) production, with heat stress projected to reduce yields by up to 10 million metric tons annually by 2050. This review synthesises current knowledge on molecular markers, genome‐wide association studies (GWAS), transcriptomics and genotype‐by‐environment (GxE) interactions as integrated frameworks for thermotolerance improvement in maize. Key quantitative trait loci (QTLs) and candidate genes—including the ZmHSF–ZmHSP regulatory module, ZmbZIP60 and ZmCDPK7—are discussed in relation to heat stress signalling and reproductive‐stage tolerance. We examine how RNA‐seq, WGCNA and single‐cell transcriptomics have resolved cell‐type‐specific heat stress responses, and highlight epigenetic mechanisms—H3K4me3‐mediated heat stress memory and DNA methylation dynamics—as emerging regulatory layers with breeding relevance. Integration of GWAS‐derived SNP markers with multi‐environment yield stability analysis using AMMI and GGE biplot models enables identification of broadly adapted thermotolerant genotypes. Applications of marker‐assisted selection, genomic selection and CRISPR‐based epigenome editing for developing climate‐resilient maize cultivars are critically evaluated. This molecular–agronomic synthesis provides actionable targets for breeding programmes aimed at narrowing the yield gap under thermal stress.
Atmospheric aerosols impact agricultural productivity via complex radiative and meteorological pathways, but their specific effects on irrigated rice systems in Bangladesh are poorly quantified. This study examines how aerosol optical depth (AOD) affects Boro rice yields across Bangladesh's eight districts from 2007 to 2023, using MODIS AOD, satellite FAPAR, FAO ET0, and meteorological data within a regression and indirect-pathway framework. Results show a spatially varied yield response: Khulna, Barisal, Rangpur, Mymensingh, and Sylhet had net positive effects (up to +7.05 in Khulna), while Chattogram, Dhaka, and Rajshahi had net negative effects (down to -0.36), indicating region-specific aerosol impacts. Across districts, aerosols showed stronger associations with minimum temperatures (R 2 up to 0.625 in Chattogram) than with maximum temperatures, implicating nocturnal thermal modification as a key mediating pathway alongside FAPAR. Seasonal analysis shows the AOD-ET0 relationship flips between seasons: negative correlations during the dry Boro season in six districts (r = -0.21 to -0.69), whereas Chattogram and Sylhet remain positive year-round, influenced more by local winds and humidity than by aerosol effects. Mann-Kendall trend analysis showed increases in ET0 and decreasing precipitation in Chattogram and Barisal during the growing period. The aridity index-yield regression identified Chattogram as most water-stress-vulnerable (R 2 = 0.826, beta = -0.523) during the growing period, while Khulna and Mymensingh exhibited contrasting positive aridity-yield relationships. These findings challenge the idea that aerosols uniformly reduce agricultural productivity and show that region-specific aerosol-climate-crop interactions need consideration in South Asia's food security and air quality strategies.
Salinity is a major constraint to soybean production in the coastal regions of the Vietnamese Mekong Delta (VMD). In this study, the salinity tolerance of seven soybean varieties was evaluated under 0 parts per thousand, 4 parts per thousand and 6 parts per thousand salinity levels (corresponding to EC values of 0.5, 6.5 and 10.6 dS m(-1), respectively) at multiple growth stages using membership function value (MFV), integrating diverse salt-tolerant traits into a single index. Seven soybean varieties were classified into highly salt-sensitive (HSS, < 0.32), salt-sensitive (SS, 0.32-0.42) and moderately salt-tolerant (MST, 0.42-0.73) based on the mean MFV (mMFV). Salt stress caused severe yield losses in AGS 85 (HSS) and MT & Dstrok; 176 (SS) varieties, while MT & Dstrok; 305, HL 09-10, Ankur, VX87-09-1 and FH 92-3 (MST) genotypes maintained 75%-92% of yield under 6 parts per thousand salinity. Using best subset selection (BSS), 12 key predictors for mMFV were identified, with number of pods (NoPo), root Na+, chlorophyll and proline content at 50 DAS (RNa(+)50, SPAD50 and Pro50), and root dry weight at R8 (RDWR8) as the most important predictors. Correlation and PCA analyses showed strong positive relationships of mMFV with NoPo, SPAD50 and RDWR8 (r = 0.90, 0.70 and 0.67) and strong negative associations with RNa(+)50 and Pro50 (r = -0.74 and -0.58). Hierarchical clustering revealed that HSS and SS genotypes failed to maintain optimal Na+/K+ balance and exhibited proline hyperaccumulation in early stages of salt stress, leading to yield reduction, whereas MST genotypes maintained higher yield by keeping favourable levels of these traits. The multiple regression model based on the 12 key traits accurately predicted observed mMFV values, confirming its reliability for genotype classification and accelerating breeding of salt-tolerant soybean cultivars in the VMD.
A selection of winter barley genotypes was investigated for their responses to water shortage under different CO2 concentrations in a greenhouse. The experiment was conducted in a 2*2 factorial design. Plants were grown either with optimum water supply or simulated drought in the BBCH 59 stage at current (similar to 400 ppm CO2) or elevated CO2 concentrations (similar to 700 ppm CO2) with identical climatic conditions. Yield parameters (aboveground biomass and grain yield), water use and water use efficiency (WUE; kg m(-3)) were calculated. Drought stress induced a decrease in yield production, and the rate of yield reduction was higher at 700 ppm CO2 concentration. On average for the genotypes studied, water withdrawal resulted in a 20.01% and 22.0% reduction in grain yield at 400 ppm and 700 ppm CO2 levels, respectively. Under optimum irrigation, BCC570, BCC607, Ketos, BCC887, HOR12808 and Kaskade showed significant positive CO2 responses. Under a limited water supply, positive CO2 reactions were only observed for BCC570, Ketos and BCC1585 genotypes; however, a significant positive CO2 reaction regarding the yield production was observed for Panda. The carbon dioxide enrichment significantly increased water use efficiency under optimum watering conditions by 24.57% and drought-stressed conditions by 21.72%. However, the water shortage significantly increased water use efficiency under both 400 ppm (10.48%) and 700 ppm (12.36%) CO2.
ABSTRACT The renewed demand for healthy, sustainable plant‐based foods has sparked increased interest in ancient grains such as emmer wheat ( Triticum turgidum ssp. dicoccum ), while their potential contribution to resilient agricultural systems has also attracted agronomic attention. Here we evaluated the agronomic performance, yield stability and adaptive potential of selected emmer wheat accessions previously identified for their potential adaptability to Mediterranean climates. Field trials were conducted across three contrasting environments in northern Israel during 2019–20. Significant genotype × environment (G × E) interactions were observed, especially for yield‐related traits. Modern durum cultivars outperformed emmer in favourable environments but experienced severe yield losses under stress. These contrasting responses highlighted the trade‐off between maximum productivity and agronomic resilience under Mediterranean environmental variability. Conversely, specific emmer accessions maintained consistent yields across environments, demonstrating superior stability in Additive Main Effects and Multiplicative Interaction (AMMI) analysis. Phenology was the key driver of crop productivity, evidenced by a significant negative correlation between days to heading and thousand kernel weight ( r = −0.80, p < 0.006). This emphasizes earliness as a crucial adaptive trait allowing emmer to escape terminal drought and heat stress typical of the Mediterranean climate. A scaled‐up semi‐commercial evaluation across diverse regions confirmed the agronomic potential of emmer adoption among farmers. Although yield improvement remains a central breeding objective, these stable, early flowering emmer lines offer valuable genetic resources for developing resilient wheat cultivars suited to future climate variability and the specific challenges of sustainable Mediterranean agriculture.
Plant growth, development and performance can all be affected by the stimulation of a vast array of physiological, biochemical and metabolic alterations in response to stressors. Plant responses to environmental transitions are highly intricate and depend on several other variables, including the genotype, age and size of the species and the progression rate and persistence of the stress factors. In the face of escalating climate and environmental concerns, greater insight into the underlying stress response mechanisms is crucial to build climate‐resilient agriculture. Owing to its model plant attributes, particularly for monocots, Brachypodium distachyon offers a powerful platform for delving into the molecular basis of biological processes. Besides, its non‐domesticated nature and natural genetic diversity may reveal some of the drivers of environmental adaptation. This review synthesises recent multi‐omics research on Brachypodium 's responses to abiotic and biotic stresses, with a focus on regulatory networks, microbiome interactions, cell wall remodelling and epigenetic stress memory. Thus, knowledge gleaned from Brachypodium research has a strong potential to be exploited for numerous biological processes in agriculturally important crop species.
Timely assessment of panicle relative water content in wheat is critical for harvest diagnosis and precision management of wheat to generate higher yield and better quality. The objective of this study was to determine the most suitable index using wheat panicle hyperspectral data for the assessment of wheat panicle relative water content. Ground‐based hyperspectral datasets were obtained during the heading‐maturity growth stage under eastern and western Guanzhong wheat eco‐sites in Shaanxi Province using the FieldSpec3 Pro spectrometer. This study systematically analysed the performance of three newly developed types of two‐band hyperspectral spectral indexes and previously published spectral indexes to estimate wheat panicle relative water content. Results showed that the newly developed two‐band index NDVI (R 1890 , R 2134 ) in eastern Guanzhong wheat eco‐sites and NDVI (R 1225 , R 1302 ) in western Guanzhong wheat eco‐sites performed best in estimating wheat panicle relative water content at the panicle scale in wheat, generating the coefficients of determination, root mean square error and residual prediction deviation values between the measured and predicted values of 0.98 and 0.98, 2.95% and 2.69%, 6.98 and 6.45, respectively. This study indicates that the relative water content of winter wheat panicles can be precisely estimated using panicle hyperspectral vegetation indexes, which aids in monitoring the wheat maturation phase.
Phosphatidylethanolamine-binding proteins (PEBPs) play crucial roles in regulating plant responses to abiotic stress. In this study, we systematically investigated the maize PEBP gene family using transgenic technology and bioinformatics approaches. We identified the phylogenetic relationships of 25 PEBP genes in the maize genome and classified them into four subfamilies comprising five branches: MFT-like, TFL1-like, FT-like-1, FT-like-2 and PEBP-like. Analysis of promoter cis-regulatory elements revealed that ZmPEBP genes contain MYB-binding sites associated with drought induction and response. Gene duplication and collinearity analyses identified 23 pairs of homologous PEBP genes between maize and rice, indicating that ZmPEBPs are closely related to OsPEBPs. Real-time quantitative PCR results demonstrated that drought stress induced the differential expression of ZmZCN3, ZmZCN6, ZmZCN10, ZmZCN11, ZmPEBP, ZmZCN2, and ZmZCN17. Correlation analysis revealed that most PEBP genes exhibited expression patterns similar to those of the stress-responsive transcription factors. Physiological and biochemical assessments revealed that compared with wild-type plants, ZmPEBP-overexpressing lines exhibited significantly higher germination rates, fresh weight and chlorophyll content, whereas malondialdehyde levels were significantly lower. In addition, the accumulation of reactive oxygen species, such as H2O2 and O2 -, in the leaves decreased, resulting in enhanced drought tolerance. This study provides a comprehensive analysis of the maize ZmPEBP gene family, offering a theoretical foundation for the functional characterisation of drought tolerance within this gene family and guiding future research in this field.
The growing population demands increased production of food crops. Modern agriculture is facing numerous challenges including urbanization, water scarcity, loss of soil integrity, climate change and biodiversity loss. In addition to these, soil salinity which has substantially increased over time due to the excessive use of fertilizers is raising concerns. The increased salinity of farming land hinders plant growth. Since the agricultural land on earth is limited, it is essential to protect that land from salinity stress and to promote crop development in affected soils. Halophytes are known for their ability to survive in hypersaline environments. They possess several mechanisms to prevent damage caused by high salt concentrations and to thrive well in such environments. Besides these mechanisms, like other land plants, they also host endophytes. These halophytic endophytes, much like other adaptive features, help halophytes in many ways to survive in harsh environments. The endophytes from these plants can be utilized as a promising supplement for supporting crop development in saline soils, as they are naturally exposed to challenging saline environments and contribute to the growth of both themselves and their host plants. The present study is an effort to identify plant growth promoting endophytes from halophytes for mitigating salt stress and promoting crop development by the seed coating method. Four halophytes from two different saline environments were selected for the study. The selected plants were identified as Rhizophora mucronata, Ceriops decandra, Ipomoea pes-caprae and Spinifex littoreus. Twelve morphologically distinct endophytes (designated as RR, RS, RL, CR1, CS, CL, SR, SS, SL, IR, IS and IL), isolated from roots, stems and leaves of these collected halophytes were characterized using conventional methods and sequencing techniques. They were then studied for their ability to promote plant growth and mitigate salt stress by analysing their salt tolerance (NaCl), phosphate solubilization, ammonia utilization, nitrogen fixation, IAA production, siderophore production and plant growth supporting enzymes. Then they were utilized as seed coats to support plant growth in Abelmoschus esculentus. All the selected isolates were identified to possess at least one plant growth promoting mechanism, and many tested positive for multiple traits. This shows that they can be effectively used in promoting plant growth in saline soils.
Waterlogging and salinity stresses significantly affect crop productivity and often coincide in nature. While adaptive responses to each of the individual stresses have been studied in detail, the traits conferring tolerance to combined stresses (and thus the most appropriate targets for breeding) remain poorly understood. In the present work, we studied the morphological and ionic responses of 11 barley varieties contrasting in salinity (NaCl) stress tolerance under waterlogging (WL) and combined waterlogging and salinity (WL + NaCl) stresses. Stress damage responses were much higher in plants under combined WL + NaCl stress than those under either stress alone. The adverse effect of combined stress was much greater in salt-sensitive varieties than in more tolerant varieties. As shown by PCA analysis, growth traits such as shoot and root biomass, number and length of adventitious roots, and K+ concentration contributed strongly to PC1. Under NaCl stress, PC1 (47%) and PC2 (24.2%) accounted for 71.2% of the variance, with growth-related traits strongly correlated with PC1, while Na+ concentration and salt damage index contributed positively to PC2. A significant negative correlation (r = -0.86 and -0.96, respectively) was found between aerenchyma score and salt damage index under WL and combined stress, respectively. Overall, PCA, membership function value analysis, and correlation matrix analysis consistently identified the number of adventitious roots, percentage formation of aerenchyma, and shoot K+ content as the traits most strongly associated with the stress damage index, highlighting their suitability as key phenotyping proxies for selection in breeding programmes.
Waterlogging damage is a key disaster threatening global crop yields. However, the impact of waterlogging stress on the growth and development of spring maize from the perspective of root-soil interaction is poorly understood. A pot experiment was conducted to explore the effects of waterlogging regimes on the root morphology, anaerobic respiration, rhizosphere soil enzyme activity, dry matter accumulation and yield of spring maize, as well as the recovery of each index after termination of waterlogging stress in 2019. The waterlogging regimes were performed for different durations (5, 10 and 15 days, respectively) at the seedling (V4) and heading (VT) stages, with non-waterlogging treatment as control (CK). Results showed that with the prolongation of waterlogging duration, root vigour, activities of invertase, urease, acid phosphatase and catalase in rhizosphere soil reduced, while the activities of lactate dehydrogenase, alcohol dehydrogenase and pyruvate decarboxylase in the anaerobic respiration pathway increased, also exacerbating the accumulation of lactic acid and ethanol, thereby reducing root length, root surface area, root activity and root dry weight. The greatest reductions in maize yield occurred at 15 days of waterlogging at the seedling and heading stages. Random forest analysis showed that root vigour was an important factor affecting root dry weight at the seedling and heading stages. The structural equation model showed that waterlogging durations and waterlogging regimes significantly affected root morphology and dry weight at the seedling stage rather than the heading stage, indicating that the seedling stage was more sensitive to waterlogging regimes than the heading stage. After the termination of waterlogging stress, maize roots recovered faster under short-term waterlogging stress than under long-term waterlogging stress. This study provided a theoretical basis for clarifying the adaptive mechanisms of crop roots under waterlogging stress.
Drought stress is a primary abiotic constraint limiting lentil (Lens culinaris Medik.) productivity globally, and identifying genotypes with stable physiological tolerance across multiple growth stages is essential for developing climate-resilient varieties. This study combined multi-season field screening of diverse lentil germplasm panel using seedling vigour derived stress susceptibility index (SSI), a measure of proportional reduction in seedling vigour under stress relative to control adjusted by overall stress intensity followed by physiological and biochemical validation of contrasting genotypes under drought stress at seedling and reproductive stages. Multi-season screening identified 11 tolerant genotypes (IC560051, IC560246, IC560032, IG134349, IC201678, P3227, IC559924,. IC559666, IG130033 and P3208 including check FLIP-96-51) with lower mean SSI rank values. Seedling vigour-derived SSI provided a proxy for selection of stress-tolerant genotypes at an early growth stage. Contrasting genotypes tolerant IC560246 and highly sensitive IC424523 along with their checks FLIP-96-51 (tolerant) and JL3 (sensitive) were evaluated for physiological traits (NDVI, canopy temperature), antioxidant enzyme activities (SOD, CAT, POX), lipid peroxidation (TBARS), root system architecture (RSA), biomass, and yield components. Tolerant genotypes maintained superior trait values under drought, with markedly smaller reductions in NDVI, biomass, and root architecture, along with elevated antioxidant enzyme activities and lower lipid peroxidation compared to sensitive genotypes. Principal component analysis indicated that antioxidant enzymes (SOD, CAT, POX) and growth traits were the key contributors to drought-stress-related variance at both stages. Correlation analysis identified traits strongly associated with seed yield (r > 0.80), including shoot and root fresh weight, number of branches, and antioxidant enzyme activities that were correlated to seed yield, while shoot dry weight, total root length, surface area, NDVI, and number of pods had strong correlations at the reproductive stage only. These traits were subsequently integrated into a multi-trait composite drought tolerance index. A promising tolerant genotype, IC560246 was identified with validated tolerance stability across growth stages, offering potential as a donor for developing climate-resilient lentil varieties.
The effect of long-term climate warming on nitrogen (N) uptake and utilisation in wheat (Triticum aestivum L.) systems is not well understood. We conducted research on it using an in situ nighttime warming (NW) experiment at heading and maturity stages of 2022-2024 and early 2015-2016 wheat growth seasons. NW significantly reduced wheat yield by 31.4% in the 2015-2016 season and remained unchanged in the 2022-2023 and 2023-2024 seasons. It significantly increased the 3-year total biomass of wheat at heading and maturity stages (excluding the maturity stage of the 2022-2023 season) by 11.4%-29.1%. NW significantly increased N accumulation in grains and plants at heading and maturity stages in the 2015-2016 and 2023-2024 seasons. NW significantly increased N translocation before wheat flowering (except for the 2022-2023 season). However, it significantly increased N translocation from stems by 42.2%-547.4% and its contribution to N accumulation in grains (CNAG), but decreased those from leaves by 10.0%-22.6% and its CNAG for 3 seasons. NW also significantly increased N accumulation after wheat flowering and its CNAG for 3 seasons. NW increased N uptake efficiency of winter wheat by 7.8%-36.9% and decreased N use efficiency by 6.1%-49.9%, with no significant difference observed in the 2022-2023 season. This study indicates that although the effect of NW on N uptake and utilisation in wheat varied among different seasons, the impact of NW on N dynamics should be considered to recommend reasonable application of N fertiliser under climate warming scenarios to ensure sustainable wheat production and minimise potential environmental pollution.
Among abiotic factors, salinity is causing increasingly devastating consequences for crop growth and productivity as it expands globally. The yield of crops is reliant on the types of salts, their severity and the type of plant-whether it is a glycophyte or halophyte-because various salts are present in ionic forms in salt-affected soils. These diverse salts, whether occurring alone or in combination, exert varying effects on plant physiology and the plant's tolerance mechanisms. To comprehensively understand the comparative influences of different salt sources on the physiological and biochemical traits of maize, which are relatively sensitive to salinity, it is essential to examine their threshold levels under saline conditions. A pot experiment was conducted under saline conditions using two different salts, NaCl and Na2SO4, applied individually and in combination (NaCl + Na2SO4) at a 1:1 ratio across five salinity levels: 0, 7, 10, 13 and 16 dS m-1, including a control that remained untreated. The results depicted that the parameters regarding physiological attributes (relative water contents [RWC], electrolyte leakage [EL] and membrane stability index [MSI]), biochemical attributes (proline and malondialdehyde [MDA]), antioxidant enzymes (catalase [CAT], peroxidase [POD] and superoxide dismutase [SOD]) and N use efficiencies (N use efficiency [NUE], physiological N efficiency [PNE], N yield efficiency [NYE], N harvest index [NHI] and photosynthetic N use efficiency [PNUE]) of maize were affected negatively by increasing the concentrations of salts. However, the severity of these effects was highly pronounced with NaCl at all concentrations from 7 to 16 dSm-1 of salinity stress as compared to Na2SO4 and their mixtures. This is primarily due to the buildup of Na+ and Cl- ions in high concentrations, particularly at 16 dS m-1. The outcomes highlight the significance of managing naturally existing salt sources in soils worldwide to alleviate their damaging effects on maize cultivation and to enhance crop resilience and productivity.
