Biological soil crusts (BSCs) are important components of dryland soils that influence nutrient cycling and soil microbial activity, yet the depth-dependent responses of BSCs-associated microbial communities to long-term nitrogen (N) enrichment remain insufficiently understood. Here, we conducted a 13-year in situ N addition experiment (0–3.0 g N m⁻² yr⁻¹) in the Gurbantunggut Desert to compare bacterial and fungal communities between the moss BSCs layer and the underlying sub-biocrust soil (0–5 cm). Microbial communities exhibited pronounced vertical differentiation, with higher bacterial and fungal biomass and higher bacterial diversity in the BSCs layer than in sub-biocrust soils. Long-term N addition produced strong depth- and taxon-dependent responses. In the BSCs layer, bacterial communities were more sensitive to N addition than fungal communities, showing reduced niche breadth and migration-related parameters and a shift in community assembly from stochastic toward deterministic processes, accompanied by decreased co-occurrence network robustness. In contrast, fungal communities in sub-biocrust soils responded more strongly than bacteria, where N addition similarly promoted deterministic succession and reduced network robustness. Structural equation modeling further indicated that N influenced microbial communities in the BSCs layer via both direct effects and indirect effects mediated by changes in soil nutrient availability, whereas responses in sub-biocrust soils were entirely nutrient-mediated. Overall, these results demonstrate that long-term N addition induces depth-dependent changes in microbial community assembly and association network structure in BSCs-associated soils, highlighting the importance of accounting for soil depth and microhabitat heterogeneity when evaluating the impacts of N enrichment on dryland soil microbial communities and nutrient cycling.

Growing populations and food demand have driven cropland expansion, but this has resulted in a decline in soil quality and posed major threats to global biodiversity. Arbuscular mycorrhizal (AM) fungi form symbiotic associations with most terrestrial plants, enhancing the adaptive capacity of these plants in adverse environments and playing a crucial role in maintaining soil health. However, the global impact of land reclamation on AM fungi and its driving factors remains unclear, creating a critical knowledge gap for sustainable land use. Based on 501 paired observations from 94 publications, we conducted a global meta-analysis to explore the impacts of land reclamation on AM fungi and the roles of climate, vegetation types and agricultural management practices in this process. Land reclamation significantly reduced the AM fungal spore density (-50.98%), richness (-23.86%) and diversity (-8.41%). Compared with forest reclamation, grassland reclamation has a greater negative impact on AM fungi. Forest reclamation has a greater negative impact on AM fungi in areas with a mean annual precipitation of 1000-1500 mm and a mean annual temperature (MAT) >20 degrees C. Grassland reclamation has a greater negative impact on AM fungi in areas with MAT <8 degrees C. In addition, we found that in reclaimed cropland, crop rotation, no tillage and organic fertilizer application effectively alleviated the negative impact of land reclamation on AM fungi spore density and species richness. Although the increase of soil available phosphorus induced by land reclamation reduces AM fungal spore density and richness, climate factors have a higher explanatory power for AM fungal variation. Synthesis and applications. The present results suggest that sustainable land management strategies should consider the effect of local climate and vegetation types on AM fungi to support the development of local land use related policies. In addition, the use of beneficial management practices is crucial for protecting underground biodiversity and maintaining soil health. These findings highlight the influence of global land use changes on underground microbial function and diversity and provide valuable insights for sustainable land management practices for biodiversity conservation and ecosystem health maintenance.

Karrikin signaling, mediated by the KARRIKIN INSENSITIVE 2 (KAI2) receptor, promotes seed germination, inhibits hypocotyl elongation, regulates root architecture, and mitigates abiotic stresses in plants. DWARF14-LIKE2 (DLK2), encoding a close homolog of KAI2, has been considered a marker gene in karrikin signaling pathway. However, the biological roles of DLK2 in plant growth, development, and abiotic stress responses are still unknown. Here, we found that DLK2 disruption significantly decreased hypocotyl elongation and cotyledon angle, while increasing root hair development and rosette leaf downward-curving. These phenotypes of dlk2 mutants are opposite to those observed in DLK2-overexpressing (DLK2-OE) plants. Furthermore, DLK2-OE plants showed significantly induced seed dormancy but reduced growth of cotyledon, rosette leaves, and primary and lateral roots in young seedlings. At later developmental stage, DLK2-OE plants displayed significantly reduced flowering and shoot branching, while showing increased stem diameter, final rosette and petal size, and seed size and weight. Transcriptome analysis of DLK2-OE leaves revealed that cell cycle, cell division, responses to abiotic stresses, and plant hormone pathways are regulated by DLK2. Consistently, DLK2-OE plants exhibited significantly smaller palisade mesophyll cell size, larger cell size in seed surface, and enhanced performance under osmotic and salt stresses. These findings demonstrate that DLK2 plays important roles in regulating plant growth and development, as well as plant stress responses, as their homologs KAI2 and D14, although with diverse functions in some growth-related traits.

Small nucleolar RNAs (snoRNAs) contribute to ribosome biogenesis and modulate various aspects of plant growth and development. Given that osmotic stress downregulates numerous genes associated with ribosome biogenesis in roots, we hypothesize that snoRNAs might function in modulating plant responses to osmotic and drought stresses. To prove this hypothesis, we assessed the role of a C/D-box snoRNA, namely the HIDDEN TREASURE 2 (HID2), in Arabidopsis thaliana responses to drought using both loss-of-function and overexpression approaches. Under drought conditions, the Arabidopsis hid2 mutant displayed a significantly higher survival rate than both wild-type (WT) and HID2-complemented plants, while HID2-overexpressing plants showed a lower survival rate than WT. A series of physiological assays indicated that the hid2 mutant maintained a slower rate of water loss and more intact cell membranes than WT plants under drought, which supported their drought-tolerant phenotype. Comparative leaf transcriptome and proteome analyses revealed that processes related to wax biosynthesis, senescence, and anthocyanin accumulation were differentially regulated between hid2 and WT plants under water-deficit conditions. Consistently, the hid2 mutant accumulated higher amounts of wax and anthocyanins and exhibited delayed leaf senescence relative to WT plants under drought. Additionally, the hid2 mutant showed improved ability to increase sensitivity to abscisic acid (ABA), scavenge reactive oxygen species (ROS), and extended root hairs. Overall, these findings demonstrate HID2's role as a negative modulator in Arabidopsis drought tolerance by negatively affecting cell membrane stability, wax and anthocyanin biosynthesis, senescence, ROS-scavenging capacity, ABA responsiveness, and root hair formation.

Saline-alkaline land serves as a potential arable land reserve for augmenting agricultural productivity and safeguarding food security. However, long-term monitoring of saline-alkaline land conversion remains challenging because of vegetation recovery, surface changes, hydrological modification, and agricultural phenology. Compared with CCDC and LandTrendr, the proposed MK-based framework detects conversion occurrence and timing while reducing dependence on dense observations, parameter tuning, and annual classification. This study examines the spatiotemporal dynamics of saline-alkaline land converted into paddies in Da'an City, utilizing Landsat time-series data (2007-2021) from the Google Earth Engine (GEE) platform. The analysis employed Mann-Kendall (MK) trend and mutation tests to monitor conversion processes and analyze spatiotemporal dynamics. Point-biserial correlation analysis was applied to evaluate the sensitivity of various remote sensing indices in detecting land conversion. The top fifteen indices, including the Land Surface Water Index (LSWI), Salinity Index 4 (SI4), and Salinity Index 5 (SI5), demonstrated strong correlations (|r| = 0.788-0.885) and significant pre- and post-conversion spectral differences (p < 0.01). Validation via confusion matrix confirmed that the June SI5 index attained the highest detection accuracy (overall accuracy: 94.15%; Kappa coefficient: 0.86), supporting the MK trend test's efficacy in monitoring conversion processes. The MK mutation test achieved 80.36% temporal accuracy in determining conversion timing. The spatiotemporal analyses identified heterogeneity in saline-alkaline land conversion patterns. Spatially, large contiguous paddy fields dominated the eastern region, whereas fragmented conversion characterized the west, with minimal activity in the central zone. Temporally, the conversion area expanded rapidly before 2015 and then gradually declined, reaching a cumulative converted area of 276.29 km(2) by 2021. This study elucidates spatiotemporal conversion dynamics to guide sustainable land use.

[This corrects the article DOI: 10.3389/fpls.2026.1770941.].

Salinity adversely affects plant growth and productivity, particularly during early developmental stages such as seedling establishment and heading. To mitigate salt stress, various natural and synthetic chemical regulators have been applied to soils and plants in crops such as wheat, rice, maize, and quinoa, as they are effective in alleviating multiple abiotic stresses. However, research on the role of melatonin in quinoa under salt stress remains limited. This study investigated the effects of exogenous melatonin on growth, osmotic regulators, inorganic ions, photosynthetic performance, and antioxidant capacity in quinoa (Chenopodium quinoa) under melatonin treatments alone (1, 10, and 100 µM), salt stress (200 mM NaCl), and combined treatments of melatonin (1µM + 200 mM, 10 µM + 200 mM, 100 µM + 200 mM). The results showed that salt stress significantly reduced the relative growth rate (RGR), fresh weight (FW), and leaf relative water content (RWC). In contrast, exogenous melatonin effectively alleviated these inhibitory effects, leading to improved growth performance under combined treatments. Melatonin application also increased photosynthetic pigment content (SPAD) across all leaf positions and significantly enhanced gas exchange parameters compared with salt stress alone. Furthermore, melatonin positively regulated osmotic adjustment by increasing soluble sugars and proline content in quinoa under salt stress. Notably, antioxidant defense was enhanced, with higher enzyme activities of SOD, POD, and CAT and a reduction in MDA content. Moreover, exogenous melatonin reduced Na+, Cl−, Na+/K+, and H2PO4− levels in leaves, stems, and roots, while increasing K+, NO3−, and SO42− levels, indicating improved ions homeostasis. This study highlights the protective role of exogenous melatonin in alleviating salt stress in quinoa, with 100 µM being an effective concentration under saline conditions.

Soil salinity, sodicity, and alkalinity are frequently intensified by field-scale heterogeneity characterized by uneven spatial distributions of salts, moisture, and nutrients. In rice systems under sodic and saline-sodic soil conditions, such heterogeneity leads to uneven crop stands, variable plant responses, and challenges in applying uniform management practices. Worse, such fields receive different amounts of amendments, while similar field management practices are frequently supplemented, reducing the efficiency of amelioration. Meanwhile, field operations such as land leveling and ploughing further redistribute salts, probably creating new heterogeneity patterns. Currently, traditional methods fail to address these complexities, resulting in inconsistent growth, inefficient resource use, and variable yields. Despite these challenges, no systematic review has addressed them. This review fills the gap by examining how spatial variability in physico-chemical and biological factors affects rice performance at critical growth stages. It also evaluates integrated strategies, including organic/inorganic amendments, irrigation and drainage, and rice varieties and their cultivation to improve rice productivity under these conditions. Our review suggests focusing on the interaction between soil heterogeneity and plant growth, and on integrating plant and soil-based management strategies with site-specific technologies, with particular focus on the critical growth stages of rice, where targeted interventions can significantly and effectively enhance rice performance in heterogeneous sodic/saline-sodic soils.

The increase of global food demand has driven extensive land reclamation and intensive agriculture, but this may also have negative impacts on soil health. Arbuscular mycorrhizal (AM) fungi are widely recognized as one of the most critical driving factors for enhancing plant growth and promoting soil health. However, the role and contribution of AM fungal communities to soil health under different land use contexts remain unclear. Here, we conducted field sampling and a greenhouse inoculation experiment and found that the soil health index (SHI), AM fungal biomass and diversity in grasslands (especially fenced protected grasslands) were significantly higher than those in croplands. Furthermore, organic agriculture alleviated the negative impacts of conventional agricultural management on SHI and AM fungi. Soil health is highly correlated with AM fungal biomass and diversity under different land use types. Further greenhouse inoculation experiment results showed that AM fungi inoculation significantly increased soil health by 8.22%. Moreover, the contribution of AM fungi to SHI was higher under sustainable land use (fenced grassland) and management (organic cropland). Importantly, AM fungi inoculation increased the correlation between SHI and plant growth. In summary, our results indicate that reducing land use and agricultural management's negative impact on AM fungi might be an important way to improve soil health and crop production.

Detecting the spatial heterogeneity of soil carbon and its key driving factors is critical for soil management. However, this remains poorly understood in saline–alkali arable soils at a large scale. In this study, geostatistical analysis combined with statistical analysis was employed to investigate the key drivers of the spatial heterogeneity of soil total carbon (TC), soil organic carbon (SOC), soil inorganic carbon (SIC), and SOC forms in the 0–20 cm and 20–40 cm soil layers in saline–alkaline soils of Da’an city (496 km2), Northeast China. (1) TC, SIC, SOC, soil dissolved organic carbon (DOC), soil mineral-associated organic carbon (MAOC), and soil particulate organic carbon (POC) exhibited distinct spatial aggregation patterns across the study area (P < 0.05). SIC constituted a large proportion of TC (53.7–58.0

BACKGROUND:Hypersaline-tolerant bacterial metabolites are believed to play a critical role in sodium detoxification and salt stress tolerance in plants; however, this mechanism needs further investigation. This study aimed to evaluate halophilic bacterial strains from hypersaline environments for their ability to increase salt tolerance in wheat seedlings through sodium‒organic acid complexation, nutrient dissolution, and improved ionic homeostasis. METHODS:The halophilic bacterial strains were isolated from hypersaline conditions of salt mines and were characterized for multiple plant growth-promoting traits. These strains were tested on wheat seedling biomass, chlorophyll, osmolyte accumulation, antioxidant defense, and ion homeostasis under salt stress. The strains were assessed for their ability to produce organic acids and increase nutrient availability by solubilizing insoluble minerals under salt stress. RESULTS:The isolated bacterial strains were salt-tolerant up to 2 M NaCl stress, solubilized insoluble minerals, and produced indole acetic acid, siderophores, ammonia, hydrogen cyanide, exopolysaccharides, and various enzymes. They were identified as Stutzerimonas stutzeri (strains MRK6 and MRK20) and Pseudomonas aeruginosa (strains MRK7 and MRK11). S. stutzeri MRK6 showed the highest increase in wheat seedling growth, chlorophyll, osmolytes accumulation, antioxidant enzymes, and ion homeostasis by increasing potassium uptake and modulating sodium toxicity under 100 mM salt stress. This increased nutrient availability from insoluble minerals. CONCLUSION:The halophilic S. stutzeri MRK6 increased salt tolerance in wheat by increasing soil mineral dissolution, sodium detoxification, and ionic compartmentalization rather than excessive sodium uptake. This mechanism offers a promising approach for mitigating salt stress in salt-affected soils.

Soil organic carbon (SOC) mineralization, driven by soil microbial communities, plays a crucial role in the global carbon cycle. However, the temperature sensitivity of microbial preferences for SOC substrates remains poorly understood, limiting our ability to predict SOC dynamics under climate change. Here we combined bacterial community profiling, laboratory incubations, and a pool-based carbon model to investigate the relationships between bacterial species abundances and two SOC pools with fast and slow decay rates, respectively, at different incubation temperatures. Only about half of identified bacterial species is significantly (P < 0.05) associated with the mineralization of the two pools and their temperature sensitivity (Q10). More importantly, we find that the association of the species with the two pools shifts in terms of both magnitude and direction with incubation temperature. The proportion of species associated with the Q10 of fast pool decreased, while those associated with the Q10 of slow pool increased with warming. Meanwhile, species specifically associated with the fast pool exhibit stronger temperature sensitivity compared to species specifically associated with the slow pool at lower temperatures, and vice versa at higher temperatures. These results suggest that common bacterial species associated with SOC mineralization adjust their substrate preferences in response to temperature variations, potentially impacting SOC composition and dynamics under warming.

Substitution of chemical fertilizers with organic fertilizers is often considered a sustainable approach that can support soil health and promote crop yield. Arbuscular mycorrhizal (AM) fungi are crucial for maintaining ecosystem multifunctionality; however, their beneficial functions are often influenced by fertilization. Up to now, the global impacts of organic fertilizers on AM fungal communities and mycorrhizal benefits on crop yield and soil health remain unclear. Here we conducted a global meta-analysis to address these knowledge gaps regarding the impact of organic fertilizers application on the growth of AM fungi, and whether AM fungi could increase crop yield and improve soil health under the condition of substitution of organic fertilizers for chemical fertilizers. Based on global meta-analysis, we found that organic fertilizers application can increase AM fungal biomass and richness by inhibiting soil acidification and increasing soil organic carbon content. Moreover, the benefits of replacing chemical fertilizers with organic fertilizers for AM fungal communities depend on the agricultural management and climatic conditions. Full substitution of chemical fertilizers with organic fertilizers significantly enhanced AM fungal spore density (SD), phospholipid fatty acids and diversity compared to partial substitution. Monoculture systems outperformed crop rotation in promoting root colonization, SD and neutral lipid fatty acids. In hot and rainy regions, replacing chemical fertilizers with organic fertilizers significantly promoted AM fungal SD and richness. It is worth noting that AM fungal richness is positively related to crop yield and soil health, further emphasizing the importance of AM fungi in promoting plant growth and maintaining soil health under organic fertilizer application conditions. These findings emphasize the unique role of enriching AM fungal communities through organic fertilizers in supporting plant productivity and soil health. Our research underscores the significance of AM fungi as a nature-based pathway for enhancing ecosystem multifunctionality and boosting nutrient utilization efficiency within agricultural ecosystems.Read the free for this article on the Journal blog.

Phosphatase activity plays a significant role in soil phosphorus (P) cycling, supporting plant growth and maintaining soil health, yet agricultural-driven land use changes have substantially regulated its activity. However, the global impact of land reclamation and vegetation restoration on phosphatase activity remains unclear. This study conducted a meta-analysis using 851 observations of phosphatases from 201 publications to explore the response of phosphatase activity to land reclamation and vegetation restoration. Land reclamation significantly inhibited soil acid (ACP) and alkaline phosphatase (ALP) activities by 28.94 % and 22.95 %, while vegetation restoration increased ACP and ALP activities by 46.10 % and 68.17 %. Phosphatase activity in forests was more influenced by land use change than in grasslands. The decreases in ACP activities from forest to cropland (- 33.25 %) were significantly greater than those from grassland to cropland (-20.11 %). Phosphatase activities were positively correlated with vegetation restoration years (P < 0.05), but not with land reclamation years (P > 0.05). Notably, during land reclamation, phosphatase activity was mainly driven by soil total nitrogen, organic carbon and microbial biomass carbon, whereas, mean annual temperature precipitation played a larger role in determining phosphatase activity during vegetation restoration. Our research suggests that land reclamation can weaken phosphorus cycling function, but targeted vegetation restoration measures, especially long-term restoration, can reverse these negative impacts. Our results highlight that it is crucial to use sustainable agricultural measures and incentivize climate adaptive land management to ensure long-term soil productivity and improve overall soil health. These findings emphasize the significant and variable influences of environmental factors on soil phosphatase activity across various land use patterns, providing valuable insights for land management and ecological restoration.

Rice cultivation is generally accepted as one of the most effective biological strategies for reclaiming saline-sodic soils and ensuring food security; however, the underlying mechanism remains unclear. Soil macropores play a critical role in complex physical coupling processes such as ion absorption and water/salt migration, which are closely associated with soil salinization and alkalization. This study sought to investigate the impact of rice cultivation duration on soil macropores, salinization, and alkalization. Intact soil columns (0-20 cm) sampled from saline-sodic paddy fields with different cultivation durations (1, 5, and 12 years) were scanned using industrial X-ray computed tomography (XCT). Soil pH, soil salt content (SSC), and sodium adsorption ratio (SAR) were measured. Compared with 1 year of cultivation, longer rice cultivation significantly increased macroporosity by 46.25 %-123.34 %, larger macropores (> 200 mu m) by 76.58 %-215.20 %, and maximum diameter pores by 30.43 %-65.22 % (P < 0.05). Moreover, macropore morphology and network parameters significantly improved with increasing cultivation duration, while soil pH, SSC, and SAR showed significant decreasing trends. Among them, SSC decreased from 5.64 g kg(-1) (1 year of cultivation) to 3.03 g kg(-1) (12 years of cultivation) [P < 0.05]. Furthermore, the structural equation model (SEM) indicated that rice cultivation years indirectly affected saturated hydraulic conductivity (K-s) by directly affecting soil macropore parameters, which ultimately affected SAR. In addition to K-s, specific surface area (SA) and fractal dimension (FD) were key factors affecting SSC. This study provides new insight into the underlying mechanisms of salinization and alkalization in rice cultivation from a macropore-scale perspective.

Biological soil crusts (BSCs) are essential components of drylands, yet the effects of their development on soil multifunctionality (SMF) and the drivers behind these effects remain unclear. We sampled 11 sites in Northwest China's deserts, representing different successional stages of BSC development (i.e. cyanobacterial, lichen and moss crusts) as well as bare sand areas. We assessed the SMF of the crust layer and underlying soil at various depths (0-2, 2-5, 5-10, 10-20 cm) and also explored the influence of climatic factors (mean annual temperature, aridity, and solar radiation), crust characteristics (compressive strength, roughness, and thickness), and soil properties (pH, electrical conductivity, soil water content) on SMF across these layers. The presence of BSCs significantly enhanced soil nutritional status [soil organic carbon (SOC), total nitrogen (TN), total phosphorus (TP), ammonia (NH4+-N), nitrate (NO3--N), and available phosphorus (AP)] throughout the 0-20 cm soil depth and increased SMF in the top 0-10 cm. These positive effects intensified with as BSCs progressed from cyanobacterial to lichen to moss stages, but decreased with soil depth. In the crust layer, SMF across all BSC types was positively influenced by our climatic factors. However, as BSCs developed, the negative influence of climatic factors (mainly solar radiation) and soil properties (mainly pH) on SMF decreased, while the positive influence of crust characteristics (mainly thickness) increased. The influence of climate, crust, and soil factors on SMF also decreased with increasing soil depth and varied by BSC type. Further, our findings demonstrate that the BSC development can buffer the negative effects of increased soil pH and solar radiation on SMF while enhancing the positive effects of crust properties, particularly thickness. This highlights the importance of preserving and promoting BSC development to enhance surface soil multifunctionality and mitigate the adverse effects of climate change on dryland ecosystem multifunctionality.

Small nucleolar RNAs (snoRNAs) function in ribosome biogenesis, and many ribosome biogenesis-related genes were downregulated by osmotic stress, implying a negative role of snoRNAs in drought tolerance. A snoRNA, namely, the NON-CODING RNA 1 (NCR1) was studied for its roles in drought tolerance in Arabidopsis. In comparison with wild-type (WT) plants, the loss-of-function ncr1 mutant plants showed enhanced drought tolerance, which was restored in the NCR1-complemented plants, whereas the NCR1-overexpressing plants revealed a drought-sensitive phenotype. Physiological analyses revealed that the ncr1 plants had a higher leaf surface temperature, lower water loss rates, and improved cell membrane integrity compared with WT. Comparative leaf transcriptomics and proteomics suggested that wax biosynthesis, anthocyanin metabolism, and leaf senescence processes are regulated by NCR1 under both normal and water-deficit conditions. Under drought, an increase in wax and anthocyanin accumulations and a delay in leaf senescence in ncr1 plants, when compared with WT, supported the transcriptome and proteomics data. Additionally, the ncr1 plants exhibited higher abscisic acid (ABA) sensitivity and longer root hairs than WT. Collectively, our results suggest that NCR1 negatively regulates drought tolerance through modification of wax biosynthesis, anthocyanin accumulation, leaf senescence, cell membrane integrity, ABA responses, and root hair development.

Soil alkalinization is a major environmental stress that severely limits plant growth and development. Rice (Oryza sativa) is a globally important food crop, and to improve its yield and quality in saline-alkaline environments, its molecular responses to alkaline stress must be better understood. Here, we cloned and overexpressed the abscisic acid (ABA)-synthesizing gene 9-cis-epoxycarotenoid dioxygenase 3 (OsNCED3) in the alkaline-resistant rice cultivar Dongdao-4 to generate three transgenic lines (OE-1, -2, and -3). These transgenic lines exhibited enhanced root phenotypes and increased tolerance to alkaline stress compared to wild-type (WT) plants. The content of ABA and activity of antioxidant enzymes, including superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), and ascorbate peroxidase (APX), were significantly higher in the transgenic lines, whereas the levels of reactive oxygen species (ROS) (O2·- and H2O2) and malondialdehyde (MDA) were reduced in the transgenic lines under hydroponic alkaline stress conditions. Transcriptome analysis of the roots under 15 mmol L-1 Na2CO3 stress identified 2915 upregulated and 2070 downregulated differentially expressed genes (DEGs) between the WT and transgenic lines. Gene Ontology (GO) and Kyoto Encyclopaedia of Genes and Genomes (KEGG) pathway analyses of the DEGs revealed enrichment in plant hormone signal transduction and MAPK signalling pathways, suggesting a role in stress response regulation. Additionally, agronomic surveys indicated that the grain yield of OsNCED3-overexpressing lines was significantly higher than that of the WT. These findings provide a theoretical and practical foundation for improving rice alkaline tolerance and productivity in saline-alkaline soils.

Ascorbic acid (ASA) is often recommended to mitigate the effects of saline stress on crop growth. However, no such research exists on its priming effect on the growth of quinoa (Chenopodium quinoa Willd.). Thus, the main goal of this study was to evaluate the potential benefits of ASA (0.1 and 0.5 μM) against salt-induced stress in quinoa seedlings. The results showed that ASA significantly improved germination, and biomass, especially fresh weight (≥47.14%) and dry weight (≥83.33%) even higher than CK, indicating enhanced plant vigor under such salt stress of 200 mM. Additionally, ASA-treated plants enhanced chlorophyll and carotenoid biosynthesis, with low ASA increased carotenoids by 95.45%, improving photosynthesis. Furthermore, ASA enhanced gas exchange, non-photochemical quenching (NPQ), and antioxidants enzymes activities, suggesting improve energy dissipation and potential support for oxidative stress tolerance. Notably, metabolic indicators, especially proline (≥29.89%) showed higher levels, indicating enhanced osmotic adjustment. Moreover, ASA effectively mitigated sodium (Na+) and chloride (Cl-) in roots through potassium (K+) uptake by at least 93.41% and elevated K+ levels by 99.76% in shoots, underscoring its role in mediating ion homeostasis under salinity. This study provides the first evidence that ASA could enhance biological, physiological and biochemical responses in quinoa. Applying ASA at 0.1 μM/L is feasible and effective as a priming concentration under suitable salt stress conditions.