The development of water-saving management relies on understanding the physiological response of crops to soil drought. The coordinated regulation of hydraulics and stomatal conductance in plant water relations has steadily received attention. However, research focusing on grain crops, such as winter wheat, remains limited. In this study, three soil water supply treatments, including high (H), moderate (M), and low (L) soil water contents, were conducted with potted winter wheat. Leaf water potential (Ψ_leaf), leaf hydraulic conductance (K_leaf), and stomatal conductance (g_s), as well as leaf biochemical parameters and stomatal traits were measured. Results showed that, compared to H, predawn leaf water potential (Ψ_PD) significantly reduced by 48.10% and 47.91%, midday leaf water potential (Ψ_MD) reduced by 40.71% and 43.20%, K_leaf reduced by 64.80% and 65.61%, and g_s reduced by 21.20% and 43.41%, respectively, under M and L conditions. Although g_s showed a significant difference between M and L, Ψ_leaf and K_leaf did not show significant differences between these treatments. The maximum carboxylation rate (V_cmax) and maximum electron transfer rate (J_max) under L significantly decreased by 23.11% and 28.10%, stomatal density (SD) and stomatal pore area index (SPI) under L on the abaxial side increased by 59.80% and 52.30%, respectively, compared to H. The leaf water potential at 50% hydraulic conduction loss (P₅₀) under L was not significantly reduced. The g_s was positively correlated with Ψ_MD and K_leaf, but it was negatively correlated with abscisic acid (ABA) and SD. A threshold relationship between g_s and K_leaf was observed, with rapid and linear reduction in g_s occurring only when K_leaf fell below 8.70 mmol m⁻² s⁻¹ MPa⁻¹. Our findings demonstrate that wheat leaves adapt stomatal regulation strategies from anisohydric to isohydric in response to reduced soil water content. These results enrich the theory of trade-offs between the carbon assimilation and hydraulic safety in crops and also provide a theoretical basis for water management practices based on stomatal regulation strategies under varying soil water conditions.

Soil salinization is a global problem that causes huge losses in agricultural production. Salt can interfere with crop absorption and metabolism of nutrients and water, affect plant physiological responses and reduce plant biomass. Maize, a very important economic crop, can adapt to a certain degree of saline-alkali soil. It is essential to understand the physiological indexes of response to soil salinity concentrations and explore the effects of different nitrogen fertilizer treatments on maize growth. In this study, three soil salinity gradients (S1, S2 and S3 were with soil salt concentration, Ssc, of 0, 0.1% and 0.25%, respectively) and two nitrogen application rates (N0 and N1 were without and with nitrogen applied (13.2 g per pot), respectively) were set up. Plant growth and photosynthetic parameters were measured. Whether nitrogen was applied or not, with the increase in Ssc, leaf area, plant height, stem diameter, SPAD, leaf water potential, RuBP carboxylase, and PEP carboxylase activities, photosynthetic rate (A), stomatal conductance (g_s), the maximum stomatal conductance (g_smax), and the stomatal morphological parameters such as stomatal width and maximum stomatal area (a_max), all showed a downward trend. Under the S1 and S2 treatments, compared with the N0, the N1 treatment alleviated the stress effect of the Ssc on these indicators. However, under S3 treatment, the stress degrees of leaf water potential, g_s, g_smax and a_max, were aggravated after nitrogen application. This indicated that under the high Ssc of S3, the interaction between nitrogen application and soil salinity should be considered. WUE_in increased with the increase in Ssc. Moreover, under N1 treatments, the increase in WUE_in with Ssc was greater than that with N0. With the increase in Ssc, whether nitrogen was applied or not, the dry weight of maize declined by 44.2% and 73.0%, respectively, for the S2 and S3 treatments. Under S2 treatment, N1 significantly improved the dry matter mass of maize compared with the N0 treatment. The results showed that soil salt stress can inhibit crop growth, physiology and dry matter accumulation, and that nitrogen application can alleviate this within a specific salinity range. Such results indicate that in saline-alkali areas, whether nitrogen fertilizer is applied or not should depend on the level of Ssc to improve plant growth.

This study was carried out to investigate effects of subsoiling on the diversity and composition of the bacterial community in a wheat–maize rotation field in the Guanzhong area of Shaanxi Province, China. After the wheat harvest, surface soil samples were collected under two tillage methods (single rotary tillage (RT) and subsoiling + rotary tillage (ST)) to perform high-throughput sequencing and bioinformatics analysis. Soil properties and root length density (RLD) of winter wheat at booting and flowering stages were also studied. Results showed that ST treatment significantly raised the water storage, organic carbon and total nitrogen contents of deep soil (>40 cm), and notably increased the total soil pH, ammonium nitrogen content and RLD in the tillage layer from 0–70 cm at booting stage and 0~100 cm at flowering stage, but the residual nitrate nitrogen significantly decreased by 17.74%. Compared with RT, soil bacterial richness and diversity in the 10~20 cm layer of ST treatment showed a significantly decreased trend. The relative abundances of GAL15, Actinobacteria, Nitrospirae, Rhizobiales, Burkholderiales, Pseudomonas and Serratia in the 10–20 cm layer were remarkably increased in ST. Principal Component Analysis (PCA) and Redundancy Analysis (RDA) results showed that surface soil pH, ammonium nitrogen and nitrate nitrogen contents have the strongest effect on the bacterial structure. In addition, there were positive correlations between the RLD and the relative abundances of Rhizobiales, Burkholderiales, Pseudomonas and the ammonium nitrogen content. In conclusion, although subsoiling was not conducive to improving soil bacterial community richness and diversity, it significantly increased soil beneficial bacteria (biological nitrogen-fixing bacteria, ammonifying bacteria, nitrobacteria) abundances, reduced the nitrogen loss caused by denitrifying bacteria, promoted earlier root development and improved the plant utilization ratio of soil nutrients.

Balancing soil nitrogen leaching with production benefits remains a critical challenge in sustainable greenhouse tomato cultivation. This study evaluated the effects of reduced water-soluble nitrogen fertilizer (N) application rates on soil environmental parameters and production outcomes to optimize nitrogen management strategies. Four treatments were implemented across two growing seasons: control (CK), high-N (H), medium-N (M), and low-N (L) nitrogen fertilizer applications in soil solution (SS) and autumn–winter (AW) systems. Results demonstrated that reduced nitrogen inputs significantly decreased soil electrical conductivity and soil nitrogen retention by 88% and 83% in SS and AW, respectively, while reducing soil residual nitrate nitrogen. The tomato yield decreased by 14–26% under low fertilizer treatment, while fruit quality was substantially enhanced, with soluble solid content increasing by 56% in SS and 217% in AW for the L treatment compared to the CK. Nitrogen-use efficiency improved by 54.7% and 34.78% in SS and AW, respectively, demonstrating superior resource utilization under reduced fertilizer applications. Principal component analysis revealed that fruit quality was primarily influenced by soluble solid content, organic acid, total soluble solids, and sugar–acid ratio. Gray relational analysis identified the L treatment (361.62 kg ha⁻¹ in SS and 182.6 kg ha⁻¹ in AW) as optimal for comprehensive performance evaluation. The findings demonstrate that strategic nitrogen reduction effectively balances production benefits with environmental sustainability, providing a practical framework for sustainable nitrogen management in controlled environment agriculture.

Drought stress severely limits agricultural productivity, with atmospheric and soil water deficits often occurring simultaneously in field conditions. While plant responses to individual drought factors are well-documented, recovery mechanisms following combined atmospheric–soil drought remain poorly understood, hindering drought resistance strategies and irrigation optimization. We set up two VPD treatments (low and high vapor pressure deficit) and two soil moisture treatments (CK: control soil moisture with sufficient irrigation, 85–95% field capacity; drought: soil moisture with deficit irrigation, 50–60% field capacity) in the pot experiment. We investigated wheat’s hydraulic transport (leaf hydraulic conductance, K_leaf) and gas exchange (stomatal conductance, g_s; photosynthetic rate, A_n) responses to combined drought stress from atmospheric and soil conditions at the heading stage, as well as rewatering 55 days after treatment initiation. The results revealed that: (1) high VPD and soil drought significantly reduced leaf hydraulic conductance (K_leaf), with a high VPD decreasing K_leaf by 31.6% and soil drought reducing K_leaf by 33.2%; The high VPD decreased stomatal conductance (g_s) by 43.6% but the photosynthetic rate (A_n) by only 12.3%; (2) After rewatering, g_s and A_n of atmospheric and soil drought recovered relatively rapidly, while K_leaf did not; (3) Atmospheric and soil drought stress led to adaptive changes in wheat’s stomatal regulation strategies, with an increasing severity of drought stress characterized by a shift from non-conservative to conservative water regulation behavior. These findings elucidate wheat’s hydraulic–stomatal coordination mechanisms under drought stress and their differential recovery patterns, providing theoretical foundation for improved irrigation management practices.

Plant cell wall-derived oligosaccharides, such as xylo-oligosaccharides (XOS), serve as key signaling molecules regulating plant growth and immunity. The bioactivity of XOS is closely tied to their degree of polymerization (DP), yet the molecular mechanisms underlying DP-specific effects remain poorly understood. Here, we investigated the transcriptional and phenotypic responses of lettuce (Lactuca sativa) to foliar application of four high-purity XOS variants: xylobiose (XOSY, DP2), xylotriose (XOSB, DP3), xylotetraose (XOSD, DP4), and xylopentose (XOSW, DP5). Phenotypic analyses revealed that high-DP XOS (XOSD and XOSW) significantly enhanced aboveground biomass and root system development, with XOSD showing the most pronounced effects, including a 31.74% increase in leaf area and a 20.71% increase in aboveground biomass. Transcriptomic profiling identified extensive transcriptional reprogramming across treatments, with XOSD eliciting the highest number of differentially expressed genes (DEGs). Functional enrichment analyses indicated that XOSD and XOSW upregulated genes involved in plant hormone signaling, starch and sucrose metabolism, and cell wall biosynthesis, while downregulating photosynthesis-related genes. Notably, MapMan and KEGG pathway analyses revealed that XOSD significantly activated biotic stress-related pathways, including MAPK signaling, β-1,3-glucanase activity, and PR protein pathways. In contrast, XOSY treatment primarily upregulated genes linked to basal immunity, highlighting distinct mechanisms employed by low- and high-DP XOS. These findings demonstrate that XOS with varying DP differentially modulate growth- and immunity-related processes in lettuce. High-DP XOS, particularly XOSD, not only promote plant biomass accumulation but also enhance immune responses, highlighting their potential as biostimulants for sustainable agriculture. This study provides a molecular framework for understanding the DP-specific bioactivity of XOS and their dual role in optimizing plant growth and defense.