This study evaluated the acclimation of eight soybean varieties to water deficit through changes in photosynthetic performance and physiological, biochemical, and epigenetic traits. Plants were grown under controlled conditions in two treatments: control (80% water-holding capacity; WHC) and drought (40% WHC). Water status was assessed using relative water content and osmotic potential, while photosynthetic performance was evaluated using gas exchange, water use efficiency, maximum quantum efficiency of photosystem II, chlorophylls, and carotenoids. Total flavonoid content, reducing power, proline accumulation, and 5-methylcytosine content were determined. Water deficit induced marked variety-specific changes across traits. The varieties Hana and Atacama maintained higher relative water content (RWC), less negative leaf osmotic potential ('Ps), and more favourable photosynthetic performance under drought, while the variety Atlas showed a favourable profile in several other traits. In contrast, the varieties Dornburg, York, and Impala showed a less favourable response, whereas the varieties Labrador and Zaria occupied intermediate positions depending on the trait evaluated. Multivariate and correlation analyses showed that photosynthetic performance was closely associated with plant water status, while stronger biochemical and epigenetic responses were more evident in less favourable or intermediate profiles. These results indicate that soybean acclimation to water deficit is coordinated and variety-specific and cannot be assessed using a single parameter.
The major objective of this study is to investigate changes in radish growth parameters (fresh and dry biomass and photosynthetic efficiency) and the stability of water-stable soil aggregates under contamination by different microplastic materials (high-density polyethylene (HDPE), polyvinyl chloride (PVC), and polystyrene (PS)) in contrasting soil types (Chernozem, Luvisol and Umbrisol). The study was conducted as a pot experiment under laboratory conditions, including three soil types and three microplastic types, with five replicates per variant. The results indicate that the effects of microplastics on plant biomass were significantly dependent on the interaction between soil type and microplastic type. In Chernozem, PS contamination significantly increased both dry and fresh biomass production (by approximately 46% and 50%, respectively) compared with the control. This response was directly associated with increased photosynthetic efficiency and greater stability of water-stable microaggregates in this variant. These findings confirm the stimulatory effect of PS on plant growth in Chernozem. The presence of PS in Chernozem appears to promote the formation of stable microaggregates and decrease macroaggregates, thereby altering the pore system (distribution of micro-and macropores) and supporting plant growth and nutrient absorption. An improvement in the stability of water-stable microaggregates was also observed in Luvisol and Umbrisol under PS contamination (statistically significant in Umbrisol); however, these changes were not reflected in the analysed plant growth parameters. In contrast, HDPE and PVC microplastic pollution had no statistically significant effect on biomass production or photosynthetic efficiency in Chernozem, Luvisol, or Umbrisol. Overall, the findings demonstrate that the effects of microplastic contamination on soil properties and plant growth are strongly influenced by both the type of microplastic polymer and soil characteristics.
To clarify the regulatory mechanisms and optimal combinations of magnesium fertiliser application rates and machine-transplanting density on rice yield, quality, and magnesium uptake and utilisation in the hilly regions of Sichuan. This study utilised a two-factor split-plot design in field trials conducted from 2024 to 2025. The main plot was magnesium application rate, with four treatments: 0 kg/ha (Mg0), 30 kg/ha (Mg1), 45 kg/ha (Mg2), and 60 kg/ha (Mg3). With the secondary factor being machine-transplanting density, comprising three treatments: 14 cm x 30 cm (D1), 18 cm x 30 cm (D2), and 22 cm x 30 cm (D3). The study investigated the effects of interactions between magnesium fertiliser application rates and planting density on rice yield components, leaf physiological characteristics, dry matter transport, and magnesium fertiliser use efficiency. The results showed that, compared with the Mg0 treatment, the Mg3 treatment significantly increased rice yield, with the best results observed in combination with the D1 treatment, yielding a 14.52% increase over the Mg0 treatment. Dry matter transport in rice increased significantly with the application of magnesium fertiliser. Compared to the Mg0 treatment, the Mg3 treatment increased stem and leaf dry matter transport by 19.64%, and post-heading dry matter transport by 30.76%; the D1 treatment further optimised dry matter transport. Compared to the D3 treatment, the amount of stem and leaf dry matter transport, the transport rate, and the contribution rate to grain increased by 26.44, 34.28, and 40.32%, respectively. Magnesium uptake and utilisation efficiency were highest under the Mg3 treatment. Compared to the Mg0 treatment, magnesium uptake and utilisation efficiency increased by 31.25%, and the physiological utilisation rate of magnesium fertiliser increased by 24.71%; under the D1 treatment, the agronomic utilisation rate and uptake and utilisation efficiency of magnesium fertiliser increased by 38.22% and 20.20%, respectively, compared to the D3 treatment. Furthermore, the Mg3D1 treatment significantly increased the rice leaf area index and chlorophyll content, while simultaneously improving rice processing and appearance quality and reducing chalkiness and amylose content. This series of measures achieved synergistic optimisation of magnesium fertiliser application rates and machine-transplanting density.
