The effects of combined salt-drought stress on rice grain quality and starch properties remain poorly understood. A pot experiment was conducted with control, salt, drought, and combined salt-drought stress. Compared with the control, rice grain yield decreased by 24.8% to 65.9% under salt, 12.4% under drought, and 25.1% to 69.5% under combined salt-drought stress. Milling, appearance, and eating quality deteriorated under stress, especially under combined stress, with a 33.0% decrease in taste value and 51.1% increase in amylose content. The amylopectin content declined, while the protein content increased, further impairing palatability. Microscopic and structural analyses revealed cracks, pores, fractured granules, and a smaller average granule size under stress, resulting in lower crystallinity and disrupted molecular order, especially under combined stress. By reducing rapidly digestible starch and increasing resistant starch, stress may help moderate postprandial glucose responses. Overall, combined salt-drought stress synergistically compromises rice yield and quality, providing insights for breeding stress-resilient, high-quality rice.

Continuous cultivation and excessive chemical fertilizer use have led to increased soil compaction in peanut (Arachis hypogaea L.) fields, significantly hindering plant growth and development. Organic fertilizer can improve soil nutrient content, aeration, and overall soil environments, thereby promoting healthy plant growth. However, the mechanisms underlying the effects of substituting chemical fertilizer with organic fertilizer on peanut growth under compaction stress are still elusive. To investigate the responses of peanut root traits, soil physicochemical properties, and microbial community structure to organic fertilizer substitution under soil compaction, a pot experiment was conducted using two compaction levels (1.2 and 1.6 g/cm3) and three organic fertilizer rates (0, 120, 240 g/pot) in Laixi, Shandong Province, a major peanut producing area. Results showed that organic fertilizer significantly improved plant biomass, height, stem diameter, and nodule fresh weight during the flowering and podding stages. Root traits including total root length, total surface area, and root volume, were significantly increased, especially at the podding stage (p < 0.05). The number of xylem vessels increased under 1.2 g/cm3 compaction but showed no significant change under 1.6 g/cm3. Soil available phosphorus and potassium contents increased with higher fertilizer rates. Distance-based redundancy analysis (RDA) showed that rhizosphere bacterial and fungal communities were affected by soil physical and chemical properties. Partial least squares path modeling (PLS-PM) indicated that soil organic matter was positively correlated with soil enzyme activity, which indirectly enhanced fungal diversity, while bacterial diversity showed negative correlation with soil organic matter. In conclusion, applying organic fertilizer in accordance with soil compaction levels offers an efficient strategy to improve soil microbial structure, enhance soil fertility, and promote peanut growth under compacted field conditions.

Soil microorganisms are critical in regulating carbon and nitrogen cycling in grasslands. Yet, their community assembly mechanisms and response patterns along precipitation gradients remain unclear in arid and semi-arid grasslands. This study explored soil microbial community characteristics and assembly processes across four grassland types along a precipitation gradient. We used Illumina high-throughput sequencing to examine soil microbial community structure, and explore network interactions and assembly mechanisms in different grasslands in Ningxia, China. Actinobacteriota and Ascomycota were the dominant bacterial and fungal phyla. Bacterial alpha diversity peaked in desert steppe, while fungal alpha diversity showed no significant differences. With declining precipitation, bacterial networks became more modular and disturbance-resistant, whereas fungal networks displayed tighter connections. Meadow steppe had the most stable soil microbial network. Bacterial community assembly was dominated by stochastic processes in desert steppe but deterministic processes in other grasslands. Fungal communities were primarily governed by stochastic processes, with dispersal limitation declining and ecological drift increasing as precipitation decreased. Bacterial communities were shaped by soil pH and total nitrogen, while fungi were driven by soil water content and ammonium nitrogen. This study reveals the pattern and driving mechanisms of soil microorganisms in arid and semi-arid grasslands, informing biodiversity conservation and microbial management under global climate change.

Soil cadmium (Cd) contamination poses serious risks to plant productivity and human food safety. Farmlands contaminated with Cd are often simultaneously affected by microplastics (MPs) and low phosphorus (LP) availability. This study investigated the combined effects of Cd, LP, and polyethylene microplastics (PE) on Cd uptake in two ryegrass (Lolium rigidum) genotypes, WALR60 and SULR1, contrasting in their sensitivity to PE stress. Both LP and PE treatments significantly enhanced Cd accumulation in plants. A synergistic interaction between LP and PE further increased Cd uptake and impaired plant growth, with the genotype SULR1 showing particular sensitivity to PE stress. Mechanistically, LP and PE promoted Cd2 + influx, likely through Ca2+-permeable channels, and upregulated key metal transporter genes such as NRAMP5 and IRT1. Furthermore, PE altered the subcellular distribution of Cd in the sensitive genotype by reducing its sequestration in the cell wall and increasing its accumulation in organelles, thereby enhancing cellular toxicity. Interestingly, for elements such as P and Ca, no significant three-way interaction (Cd × LP × MP) was observed; instead, the combined effect was best presented as Cd + LP × MP. The significant Cd × LP × MP effect on biomass of the sensitive genotype may result from the integrated regulation of multiple physiological networks. Overall, this study provides new insights into plant adaptive responses under combined Cd, LP, and MP stresses, contributing to a better understanding of complex pollution scenarios in agricultural soils.

Fertilization and rhizosphere effects co-regulate soil N cycling and bacterial succession, with mechanistic understanding being key to improving crop yield and N transformation in intensive farmland. Based on a 16-year field experiment, six fertilization treatments with urea (U) and manure (M) alone or in combination (CK, U200, U100, M200, M100, and U100M100; subscript numbers denote nitrogen application rates in kg N ha-1) were established to clarify the responses of bacterial communities in two components (bulk and rhizosphere) and their associations with N dynamics and maize yield. Relative to U200, U100M100 increased grain yield by 5.6%-6.5% (2023-2024), and improved N uptake and nitrogen-use efficiency, while reducing total N loss by 44% and N footprint by 45% (average 2024-2025). Manure substitution enriched copiotrophic phyla (Proteobacteria and Bacteroidota), particularly under manure-only treatments. U100M100 lowered network complexity and increased negative interactions, while decreasing N-loss-associated ASVs. Moreover, U100M100 raised the functional potential of genes regulating nitrification, dissimilatory nitrate reduction to ammonium and N fixation in bulk soil, while promoting complete denitrification in the rhizosphere. Enriched dominant phyla and divergent N-cycling gene profiles were closely associated with N losses. Nitrogen-cycling genes and ecological modules exhibited the strongest standardized total effects on plant N uptake and maize yield. Mantel tests and PLS-PM R2 comparisons further confirmed that rhizosphere microbial communities were more strongly associated with these agronomic variables than bulk soil communities. In summary, the U100M100 treatment may establish a synergistic and efficient N-cycling system, in which the rhizosphere functions as an N loss mitigation module while bulk soil serves as an N supply module. This spatial functional divergence may result from reshaped microbial communities, reconstructed network topology and altered N-cycling functional potential.

Knowledge of the maize pollen development stages at which high temperature (HT) stress leads to male sterility and yield loss would support targeted breeding strategies. In a cross between Zhengdan 958 (HT-tolerant) and Xianyu 335 (HT-sensitive) the contributions of maize traits to effective grain number (EGN) loss under HT stress were measured during pollen development stages, with loss increasing with the approach of flowering. Traits including pollen number per anther, total tassel spikelets, and pollen germination and shedding were the strongest contributors at various stages. The stage-specific vulnerabilities of maize tassels to HT stress suggest increasing pollen production before the tetrad stage and increasing pollen fertility and shedding during the microspore development stage. In the short term, increasing pollen developmental quality offers the greatest potential for reducing HT-caused EGN loss.

Heat stress has become a major constraint on crop production under global warming, often occurring as short-term heat waves. However, the precise time point at which maize pollen begins to respond to heat stress remains unclear. In this study, we used a heat-tolerant maize variety (Zhengdan958, ZD-tol) and a heat-sensitive variety (Xianyu335, XY-sens) to investigate pollen responses under heat stress. Plants were exposed to 36±2°C/28±2°C (day/night) for seven consecutive days during anthesis, with 29±2°C/20±2°C (day/night) as the control. Pollen reactive oxygen species (ROS), callose deposition, lipid droplets, and fertility were monitored over time to determine the onset of heat effects. In both maize varieties, heat stress triggered oxidative stress and irregular callose deposition within 30 min but had no significant effect on pollen fertility. After 2 h, pollen lipid droplets decreased, and viability and germination significantly declined by 18% and 29%, respectively, resulting in a 34% reduction in grains per ear. Thus, the 2-h of heat exposure represented a critical window for the onset of pollen fertility decline during anthesis. Compared with ZD-tol, XY-sens exhibited a significantly reduced anther dehiscence area, higher oxidative accumulation in pollen, more severe irregular callose deposition, greater decrease in lipid droplet number, larger losses in pollen quantity and fertility, and more severe yield reduction. Application of ROS inhibitors significantly alleviated heat-induced damage and reduced yield losses. Notably, heat stress during pollen germination caused more severe fertility impairment than stress before germination. These findings highlight the temporal dynamics of pollen responses to heat stress and provide insights for improving maize heat tolerance.

Context: Southwest China is one of the largest karst regions, where nitrogen (N) deficiency and poor management limit crop productivity. Maize-soybean intercropping is a widely adopted planting model used by farmers across China. Therefore, innovative crop management practices to improve productivity in this region are essential to ensure China's food security. Objective and methods: Ridge-furrow with film mulching (RFM) combined with N supply was introduced for the first time into the maize-soybean intercropping system. Eight treatment combinations (maize and soybean monocultures (M), maize-soybean intercropping with RFM and with ridge-furrow (RF) under 0 (N0) and 150 (N150) kg N ha-(1) supply) were used to investigate changes in seed yield, land use efficiency, biomass, N uptake, and root morphological and physiological traits from 2020 to 2023 in Southwest China. Results: The results showed that introduction of RFM into the maize-soybean intercropping system significantly increased maize (13 %) and soybean (42 %) seed yields and land equivalent ratio (LER) (25 %) compared to ridge-furrow without film mulching. Meanwhile, N150 significantly increased maize (33 %) and soybean (24 %) seed yields compared to N0 across four years. The high LER was attributed to the increased yields of maize and soybean, which were associated with higher biomass and N uptake under RFM. The promotion of root growth, such as increased root length and carboxylate release with RFM, enhanced N uptake in both maize and soybean was observed across three years (2021-2023). In addition, N application significantly increased biomass accumulation, N uptake, root length, and carboxylate release at two developmental stages across two years (2022 and 2023), thus contributing to higher seed yields in maize and soybean. Conclusion: RFM combined with N supply can further increase crop yield and land use efficiency in maizesoybean intercropping systems in karst areas. This improvement is explained by the enhancement of the "Ncapture", related to root morphological traits, and "N-mining", related to carboxylate release, which together increase N uptake, biomass, and ultimately seed yield. Implications: RFM combined with N addition could be considered an efficiency strategy to increase crop productivity in maize-soybean intercropping systems in karst agroecosystems. Our results provided insights into the effects of crop management practices and N addition on N-acquisition strategies and their roles in nutrition uptake and yield formation.

"Hidden hunger" and heavy metal contamination in agricultural products pose critical challenges to agricultural security, with microbial inoculants offering a potential pathway for synergistic mitigation. This study conducted a systematic meta-analysis from 442 studies, exploring the regulation and mechanisms of microbial inoculants on crop essential and toxic heavy metal contents. Results indicate that microbial inoculants significantly enhance crop growth, increasing essential heavy metals accumulations including Cu, Fe, Mo, and Zn by 10-20%, while reducing the toxic metals contents like Cd and Pb by 20%. These processes are influenced by inoculant type, crop species, and soil conditions. The reduction of toxic metals is attributed to microbial diversity-mediated synergistic regulation. Machine learning results indicated that soil pH, total nitrogen, and organic matter were key factors influencing the essential heavy metals accumulation after inoculation. Organic matter, available phosphorus, and pH were key factors influencing the toxic heavy metals accumulation. Under toxic metal stress, inoculation could alter photosynthetic pigment dynamics and stabilize photosynthesis. Exogenous essential metals inhibited microbial enhancement of soil microbial diversity and saturated plant uptake, yielding no synergistic benefits when combined. Microorganisms only achieve decoupling of Fe, Mn, Mo, and toxic heavy metals. Since Cu, Ni, and Zn exist as ions or in weakly chelated forms, they remain at risk of co-transportation. This study provides an unbiased assessment of feasibility and limitations of microbial inoculants in improving food nutritional quality, alleviating "hidden hunger," and ensuring agricultural product safety.

Global climate change is increasing the frequency of concurrent heat and drought events, highlighting the urgent need to elucidate their synergistic effects on crop root function and nutrient uptake. We subjected maize plants to normal condition (CK), heat stress (H), drought stress (D), and combined heat and drought stress (HD) at the 12th fully expanded leaf stage (V12) for five days. The root-to-shoot ratio decreased under H but increased under D. Both single stresses induced “low-cost” root anatomical changes. Under HD, however, these anatomical alterations were most pronounced. They coincided with the strongest oxidative damage, the greatest suppression of root respiration, and the most severe cellular energy deficit. This energy limitation downregulated key nitrogen assimilation enzymes (NR, GS, and GOGAT) and impaired the compensatory upregulation of glutamate dehydrogenase observed under single stresses. Consequently, root nitrogen uptake efficiency declined by 9.0%, 10.4%, and 18.0% under H, D, and HD, respectively. Total plant nitrogen accumulation was lowest under HD, with nitrogen allocation increasingly skewed toward the shoot. Grain yield also lowest under HD. Collectively, these findings demonstrate that combined heat and drought cause oxidative damage, which in turn worsens the energy deficit in roots and suppresses nitrogen assimilation, thereby reducing nitrogen acquisition efficiency in maize.

Antimony (Sb) induces detrimental toxicities on plant growth, yet the underlying mechanisms are under-explored. In this study, a comprehensive approach combining physiological and transcriptomic analyses was adopted to investigate the morpho-physiological, biochemical and molecular responses of wheat to Sb toxicity. The results showed that Sb treatments (> 10 mu M) significantly reduced wheat biomass accumulation (by 52.2 %-67.8 % in shoots, and 24.9 %-56.3 % in roots) through inhibiting root development and impaired photosynthetic performance, accompanied by elevated malondialdehyde (MDA) levels. At 25 mu M Sb, the antioxidant system and its corresponding genes responded dynamically to oxidative stress, while cell wall components and metal/metalloid transporter proteins synergistically contributed to Sb detoxification and tolerance. Notably, Sb stress upregulated BIN2-related genes in the brassinosteroid (BR) signaling pathway, thereby suppressing BZR1/2 expression and disrupting BR signal transducion. Furthermore, exogenous BR application mitigated Sb-induced growth inhibition by reducing MDA accumulation and restoring growth parameters. These findings reveal key molecular mechanisms underlying wheat's response to Sb toxicity and highlight the potential of BR application as a strategy to enhance Sb tolerance in wheat.

Rice root exudates are known to suppress nitrification and mitigate nitrogen losses in agricultural soils; however, their specific roles in coastal saline soils remain poorly understood. Here, root exudates were collected at 6 and 10 weeks after transplanting from two genotypes (Oryza sativa L. 'Nanjing 9108' and 'Yangjing 5118') using a hydroponic system, and their effects on nitrification in coastal saline soils were investigated through microcosm experiments integrating metabolomic and metagenomic analyses. Root exudates inhibited net nitrification rate (NNR) and potential nitrification activity (PNA), with the inhibitory effect primarily dependent on genotype. The abundance of nitrification genes was not significantly altered by root exudates and was negatively correlated with PNA, suggesting that root exudates mainly inhibited heterotrophic rather than autotrophic nitrification. Root exudates at 10 weeks after transplanting significantly increased the abundance of nitrate reduction genes. Integrated analyses revealed that differential metabolites dominated by terpenoids and lipids, as well as several exudates (e.g., L-isoleucine, L-valine, and pyridoxine) that generated reducing electrons during metabolism, particularly in treatments with root exudates from Nanjing 9108, showed a negative correlation with PNA and positively correlated with the abundance of nitrate reduction genes. Furthermore, the mechanisms of NNR inhibition varied with genotype. Specifically, root exudates from Nanjing 9108 inhibit NNR synergistically by reducing heterotrophic nitrification and promoting nitrate reduction, whereas those from Yangjing 5118 inhibit NNR mainly by reducing heterotrophic nitrification. Overall, root exudates primarily enhance nitrate reduction and/or reduce PNA by creating microhabitats and generating reducing agents, which inhibit nitrate accumulation in coastal saline soils. These findings provide a scientific basis for the formulation of nitrogen management measures in coastal saline paddy fields.

This study aimed to explore changes in soil microbial co-occurrence networks and functional potential, and reveal the mechanisms driving maize yield improvement under 14-year fertilization. Treatments included no nitrogen (CK), urea (U1/U2, 200/100 kg N ha⁻1), manure (M1/M2, 200/100 kg N ha⁻1), and manure plus urea (U2M2). We determined soil nutrients, enzyme activities, bacterial and fungal community compositions, network properties, functional potentials, and maize grain yield. The 14-year fertilizer treatments significantly increased soil nutrients and led to a yield increase of 12

Context Soil salinization is an increasing constraint on rice production, severely limiting nitrogen utilization and grain yield. Partial substitution of mineral nitrogen with organic amendments is widely proposed to improve soil fertility and crop performance; however, its effectiveness is highly variable and may depend on salinity level. The optimal substitution strategy and the underlying soil–plant mechanisms under saline conditions remain poorly understood. Objective This study aimed to determine the optimal organic nitrogen substitution rate under contrasting salinity conditions and to elucidate the mechanisms governing yield formation, nitrogen dynamics, and methane (CH4) emissions in rice systems. Methods A two-year field experiment was conducted under lightly saline (LS) and heavily saline (HS) soils with five organic substitution rates (10–50%). Grain yield and its components, dry matter accumulation and partitioning, nitrogen accumulation, translocation and use efficiency, soil inorganic nitrogen and enzyme activities, root physiological traits, photosynthetic performance, and CH4 emissions were simultaneously measured. Results The optimal substitution rate was strongly salinity-dependent, peaking at 40% under LS and 20% under HS. Under LS, favorable yield performance was associated with coordinated grain filling, reproductive dry matter allocation, and root physiological function, whereas under HS, yield was primarily constrained by sink establishment, with spikelets per panicle showing the strongest response. Moderate substitution improved the coordination between biomass partitioning and reproductive development, while excessive substitution promoted vegetative growth without increasing yield. Nitrogen translocation contributed negatively to yield under LS but positively under HS, indicating a shift from reliance on current nitrogen uptake to remobilization under stress. Soil nitrate nitrogen availability, root physiological activity, and photosynthetic capacity were optimized at moderate substitution rates, particularly under HS. In contrast, higher substitution rates increased CH4 emissions, consistent with enhanced methanogenic potential, leading to higher greenhouse gas intensity under HS. Conclusions Salinity fundamentally alters the optimal organic nitrogen substitution strategy by shifting the physiological and ecological drivers of yield formation. A substitution rate of 40% is optimal for LS because it best balances yield components and reproductive growth, whereas 20% is more appropriate under HS to maintain sink formation and root function while minimizing yield-scaled CH4 emissions. These findings highlight the necessity of salinity-specific nitrogen management strategies to achieve both high productivity and environmental sustainability in rice systems.

Ridge-furrow with film mulching (RFM) increases grain yield by enhancing nutrient uptake and biomass accumulation in monoculture systems. However, its effects on transformation of phosphorus (P) concentration in rhizosheath soil and its role in yield enhancement in maize-soybean intercropping systems under acidic soil conditions, where low P availability in soil limits productivity, remain unclear. A 4-year field experiment with four different treatments was conducted to investigate the effects of film mulching on grain yield, root traits, P concentrations in rhizosheath soil, P-solubilising microorganisms (PSMs) and P-cycling functional genes in a maize-soybean intercropping system. The four treatments given were as follows: ridge-furrow without film mulching at 0-kg P ha(-1) (CK), ridge-furrow without film mulching at 90-kg P ha(-1) (P90), RFM at 0-kg P ha(-1) (FM) and RFM at 90-kg P ha(-1) (P90 + FM). The results showed that FM considerably enhanced seed yield, P uptake, root length, concentration of plant-available P in rhizosheath soils, acid phosphatase activity and Al-bound P in maize and soybean. FM remarkably reduced the diversity of maize rhizosheath PSMs, as indicated by a lower Shannon index. Permutational multivariate analysis revealed that FM notably altered the composition of rhizosheath PSMs in both the crops. Furthermore, FM notably increased the abundance of functional genes responsible for organic-P mineralisation, inorganic-P solubilisation, P-starvation response regulation and P transport in rhizosheath soils of maize and soybean. Structural equation modelling demonstrated that FM enhanced P transformation in rhizosheath soils, leading to increased concentrations of plant-available P, improved root morphology and better P uptake-ultimately contributing to higher maize and soybean grain yields in the maize-soybean intercropping system. In conclusion, RFM considerably improved maize and soybean productivity in acidic soils by promoting P transformation, stimulating root growth and increasing rhizosheath PSM abundance as well as increased expression of their P-cycling functional genes. These findings highlight RFM as a sustainable cultivation practice for achieving high grain yield and P-acquisition efficiency by enhancing plant-microbe interactions in maize-soybean intercropping systems.

Soil microbial communities are a key component of mountain ecosystems in arid zones. However, their changing patterns along altitudinal gradients remain unclear, hindering the understanding of mountain soil ecosystems in arid areas. In this study, soil samples were collected from the western slope of Helan Mountain, northwest China at different elevations (1800-3000 m), and plant diversity, soil physicochemical properties, soil microorganisms were measured at various elevations to further investigate the regulation of soil microbial communities. The results showed that the species richness (Chao1 index) of soil bacterial and fungal communities exhibited a generally similar pattern, they were lower in the desert steppe at low elevations, significantly increased in the arboreal forest at mid-elevations, and then gradually decreased as elevation increased toward the alpine meadow. Random forest models identified soil pH, soil organic carbon (SOC), elevation as the strongest predictors of bacterial Alpha diversity (Chao1: R-2 = 0.18, Shannon: R-2 = 0.20; P < 0.001) and community composition (R-2 = 0.67, P < 0.001). In contrast, fungal richness (Chao1) was mainly driven by soil water content (SWC), elevation, SOC (R-2 = 0.35, P < 0.001), while fungal diversity (Shannon) was governed by SWC, SOC and elevation (R-2 = 0.12; P < 0.001). Across vegetation types, fungal community composition mirrored bacterial patterns and was primarily controlled by elevation, SOC, SWC, total phosphorus, bulk density and ammonium nitrogen (R-2 = 0.69; P < 0.001). Bacterial co-occurrence networks were highly modular in the arboreal woodland (Modularity >0.9), with strong positive correlations between core bacterial phyla (Positive links >60 %), contributing to community stability. Core taxa such as Ascomycota and Basidiomycota dominated the network structure and community stability in fungal co-occurrence networks. Changes in elevation, vegetation type, and soil factors significantly affected the topology of the co-occurrence network, and the interaction characteristics of bacterial and fungal co-occurrence networks differed. This study deepens the understanding of soil microbial communities in mountainous areas of arid zones and contributes to the sustainable development and conservation of ecosystems in this region.

Saline fields hold great promise for boosting rice production in China. Salinity-tolerant/susceptible rice cultivars respond differently to salinity, yet limited research has focused on how salinity modulates their agro-physiological traits and grain yield of rice under saline field conditions. This research aimed to explore how salinity affects rice yield formation and identify key agro-physiological characteristics underlying differential tolerance responses. Field experiments were conducted with salinity-tolerant rice (Yannongjing 3426 and Nanjingyan 1) and salinity-susceptible rice (Wuyunjing 30 and Huajing 5) under low salinity (LS) and high salinity (HS) over 2 years. Rice grain yield was reduced by 34.2%-54.9% at HS across 2 years, compared with LS. The increased salinity stress led to lower shoot biomass and stem non-structural carbohydrate (NSC) content, accompanied by higher harvest index and NSC reserve remobilization. Meanwhile, the increased salinity stress brought higher leaf (sodium) Na+ concentration and Na+/(potassium) K+ ratio, accompanied by reductions in post-heading leaf SPAD value and photosynthetic rate, and total accumulation of nitrogen (N), phosphorus (P), and K. Salinity-tolerant rice yielded 10.1% (LS) and 27.1% (HS) more than salinity-susceptible rice. Salinity-tolerant rice at HS maintained lower leaf Na+ concentration and Na+/K+ ratio, but higher shoot biomass and harvest index, post-heading leaf SPAD value and photosynthetic rate, stem NSC content and remobilization, K+ concentration in leaf, and total N, P, and K accumulation than salt-susceptible rice. The present study indicated that salinity stress reduced rice grain yield by 34.2%-54.9%. The superior yield of salinity-tolerant rice over salinity-susceptible rice under HS was attributed to larger sink size and higher sink-filling efficiency, driven by the favourable agro-physiological traits.

Soil salinity is a major constraint to wheat production worldwide. Efficient screening of salt-tolerant cultivars is essential for breeding programs, yet a rapid and reliable evaluation system based on full-life-cycle salt stress treatment is lacking. To address this, we conducted a hydroponic experiment encompassing the entire growth cycle of 37 wheat cultivars under control and salt stress (85.5 mM NaCl). Using principal component and stepwise regression analyses on 15 agronomic and yield-related traits, we identified five key indicators-total dry weight, root dry weight, plant height, thousand-grain weight, and number of grains per spike-that effectively represent overall salt tolerance. Based on a comprehensive evaluation value (D-value), the cultivars were classified into five distinct categories: highly salt-tolerant, salt-tolerant, moderately salt-tolerant, weakly salt-tolerant, and salt-sensitive. Notably, the highly salt-tolerant cultivar 'Yangfumai 8 ' and the salt-sensitive cultivar 'Yangmai 22' were selected as representative extremes. A subsequent pot experiment confirmed significant physiological differences between them in antioxidant enzyme activities (SOD, POD, CAT) and proline accumulation under salt stress. This study establishes a practical and efficient screening framework, providing breeders with a simplified index set for high-throughput evaluation and offering ideal contrasting materials for in-depth physiological research on salt tolerance mechanisms in wheat.

Appropriate application of nitrogen (N) and calcium (Ca) can significantly enhance crop growth, photosynthetic efficiency, and yield formation. However, the physiological and molecular regulatory mechanisms underlying optimal N and Ca management in pakchoi remain poorly understood. To address this, a controlled soil pot experiment was conducted to systematically investigate the morphological, physiological, and transcriptomic responses of pakchoi to varying levels of N (0, 225 kg N & sdot;hm-2) and Ca (0, 75, 150, 225 kg CaO & sdot;hm-2). Results showed that the combined application of 225 kg N & sdot;hm-2 and 150 kg CaO & sdot;hm-2 (N225Ca150) maintained an optimal canopy microenvironment, significantly improved growth parameters, and increased chlorophyll content and photosynthetic efficiency. Compared to N225Ca0, the N225Ca150 increased fresh and dry weights by an average of 12.01% and 25.37%, respectively. Transcriptomic analysis revealed that under N-deficient conditions Ca enhanced the plant's adaptation by regulating the expression of genes involved in key metabolic pathways such as transcription factors and MAPK signaling cascades to modulate the growth, development, and stress response of pakchoi. However, Ca further promoted the expression of genes related to photosynthesis and N-Ca metabolism, metabolism, improving N assimilation and Ca fixation efficiency, and facilitated photosynthate production and yield enhancement under sufficient N conditions. Comprehensive analysis indicates that N and Ca exhibit synergistic effects at both physiological and molecular levels, collectively regulating the growth, development, and metabolic responses of pakchoi. Overall, the combined application of N and Ca (N225Ca150) is recommended as the optimal management practice. The findings provide a theoretical framework for understanding N-Ca interactions in pakchoi and offer practical insights for precision nutrient management in controlled cultivation systems.