Soil salinization is a growing concern that degrades soil quality and inhibits agricultural productivity. Miscanthus species have received wide attention because of their high calorific potential, their value as an energy plant, and their ability to maintain high biomass accumulation. However, most studies focused on the biochemical and physiological responses to salt stress while neglecting the osmotic adjustment processes and the contribution of both organic and inorganic substances to these processes. This study evaluates the response mechanism of Miscanthus sinensis to salt stress (0-300 mM of NaCl) by evaluating the growth and photosynthetic parameters, photosynthetic response to light, and contribution of organic and inorganic substances to osmotic potential. The results revealed that M. sinensis adopted Na + compartmentalization and reallocation of biomass to the aboveground parts to mitigate the negative impact of salinity stress. Specifically, Na+ accumulated more in the root and leaf, with an increment magnitude of 75.4-173.9 and 56.7-217.1 times, respectively. This was supported by the changing trend of the stem/leaf ratio (25.1 %-55.9 %) compared to the root/shoot ratio (12.3 %-18.3 %). Also, salt-induced stress decreased the leaf's water content and water use efficiency as a result of low intracellular osmosis, and to mitigate osmotic damage, M. sinensis enhanced the accumulation of proline. These results offer theoretical and scientific insights into managing the cultivation and improving the yield of M. sinensis and other energy herbaceous plants in saline soils.

The negative impact of climate change is potentially damaging agroecosystem services that have constrained agricultural production and caused water scarcity in Central Asian countries, particularly in Uzbekistan. This study evaluates the efficiency of full (FDI) and deficit (DDI) drip irrigation regimes for amaranth (Amaranthus spp.) cultivation in the Tashkent region of Uzbekistan using the HYDRUS-1D simulation model. Field experiments were conducted over two growing seasons, accompanied by soil moisture monitoring, root zone analysis, and crop performance measurements while the accuracy of the obtained results was assessed against ground measured data. The results showed that compared to the FDI regime, amaranth under the DDI improved water productivity by 56.5% while exhibiting tolerance to water scarcity. The Pearson correlation analysis revealed a strong relationship between the simulated and observed SWC data for both irrigation regimes (R2 = 0.862 for FDI and R2 = 0.936 for DDI), indicating the model's predictive reliability. Although FDI produced higher yield (2004 kg/ha) over the two-year period, which was 25% (2 t ha-1) higher than the DDI regime (1,604 kg/ha). However, DDI demonstrated significantly greater water productivity (56.5% higher), attributed to reduced unproductive evaporation and the C4 nature of amaranth. Root system analysis revealed deeper penetration under DDI, suggesting adaptive responses to water stress. The findings of this study suggest that implementing precise irrigation technology in amaranth cultivation combined with the use of the HYDRUS-1D model in the context of inevitable climate change, can ensure the long-term sustainable management of water and land resources in arid regions.

D ROUGHT is a highly damaging abiotic stress that affects crops' development, functioning, productivity, and quality. In contemporary farming, nanoparticles are advantageous because of their extensive surface area and enhanced ability to penetrate plant leaves when applied as a spray. Lately, nano-fertilizers have been employed in agriculture to help reduce the negative impacts of drought stress. This study aims to investigate the effects of different forms (nano and chelated) of iron (Fe), zinc (Zn), and manganese (Mn) foliar application, as well as their combinations, on the growth, yield, and water productivity of faba bean plants under different soil moisture levels (100, 80, and 60% of field capacity, FC). The results indicated the best readings of traits studied in the faba bean plant were observed under soil moisture at 100% of FC (control) compared to 60% of FC. On the other hand, results showed that the combined foliar application (FA) of FeZnMn-nanofertilizers (FeZnMn-NFs) to faba bean plants yielded the most favorable growth characteristics and chlorophyll content compared to the untreated plants (control). Also, the FA of FeZnMn-NFs treatment resulted in the highest seed yield and macronutrient (NPK) content in both straw and seed. The seed yield under FeZnMn-NFs treatment (21.24 g pot-1) was significantly more significant than the control (15.47 g pot-1). Regarding water use efficiency (WUE), the FeZnMn-NFs treatment achieved the highest WUE for the faba bean (2.44 kg m-3) compared to the control (1.60 kg m-3). Conversely, the amount of irrigation water applied (IWA) was lowest with the FeZnMn-NFs treatment (8.72 L pot-1) compared to the control (9.64 L pot-1). Concerning the interaction between irrigation levels and foliar spray treatments of faba bean plants, there were no significant differences in seed yield between the 100% irrigation level and the 80% level when foliar application of FeZnMn-NFs. Additionally, nano-fertilizers (NFs) demonstrate greater effectiveness than chelated fertilizers (EDTA), significantly enhancing yield and macronutrient content. Thus, the results highlight the crucial role of NFs in mitigating damage from drought stress, improving growth characteristics, and saving 20% of the amount of IWA for faba bean plants, allowing it to be used elsewhere in agriculture. Consequently, these findings suggest that using NFs of Fe, Zn, and Mn as foliar applications (FA) could be a promising approach to boost the growth parameters, seed yield, and WUE of faba bean plants in arid and semi-arid regions.

Despite the extensive research conducted on plant-soil-water interactions, the understanding of the role of plant water sources in different plant successional stages remains limited. In this study, we employed a combination of water isotopes (delta 2H and delta 18O) and leaf delta 13C to investigate water use patterns and leaf water use efficiency (WUE) during the growing season (May to September 2021) in Hailuogou glacier forefronts in China. Our findings revealed that surface soil water and soil nutrient gradually increased during primary succession. Dominant plant species exhibited a preference for upper soil water uptake during the peak leaf out period (June to August), while they relied more on lower soil water sources during the post-leaf out period (May) or senescence (September to October). Furthermore, plants in late successional stages showed higher rates of water uptake from uppermost soil layers. Notably, there was a significant positive correlation between the percentage of water uptake by plants and available soil water content in middle and late stages. Additionally, our results indicated a gradual decrease in WUE with progression through succession, with shallow soil moisture utilization negatively impacting overall WUE across all succession stages. Path analysis further highlighted that surface soil moisture (0- 20 cm) and middle layer nutrient availability (20- 50 cm) played crucial roles in determining WUE. Overall, this researchemphasizes the critical influence of water source selection on plant succession dynamics while elucidating un- derlying mechanisms linking succession with plant water consumption.

Background Stable carbon isotope composition (delta C-13(p)) can be used to estimate the changes in intrinsic water use efficiency (iWUE) in plants, which helps us to better understand plants' response strategies to climate change. This study focused on the variations in delta C-13(p) and iWUE for the different life-form plants (i.e., herbs, shrubs, and trees) along an altitudinal gradient (3300, 3600, 3900, 4100, 4300, and 4500 m) on the eastern slope of Yulong Snow Mountain, southeastern margin of the Qinghai-Tibet Plateau. The response mechanisms of delta C-13(p) and iWUE for different life-form plants to altitude were thoroughly analyzed in this mountain ecosystem. Results The delta C-13(p) values of plants on the eastern slopes of Yulong Snow Mountain ranged from - 30.4 parts per thousand to - 26.55 parts per thousand, with a mean of - 28.02 parts per thousand, indicating a dominance of C-3 plants. The delta C-13(p) and iWUE values varied among different life-form plants in the order of herbs > shrubs > trees, particularly in 3600, 3900, and 4300 m. The delta C-13(p) and iWUE values for herbs and shrubs increased with altitude and were mainly controlled by air temperature. The two parameters for trees exhibited a trend of initial decrease followed by an increase with altitude. Below 3900 m, the delta C-13(p) and iWUE values decreased with altitude, influenced by soil moisture. However, above 3900 m, the two parameters increased with altitude, mainly regulated by air temperature. In addition, iWUE was positively correlated with leaf P content but negatively correlated with leaf N:P ratio, especially for herbs and trees, suggesting that P plays a key role in modulating iWUE in this region. Conclusions The differentiated responses of water availability for different life-form plants to a higher altitudinal gradient are regulated by air temperature, soil moisture, and leaf P content in the Yulong Snow Mountain. These results provide valuable insights into understanding the water-carbon relationships in high-altitude ecosystems.

Extreme climate occurred frequently in subtropical region, which seriously affects carbon and water fluxes such as evapotranspiration (ET) and gross primary productivity (GPP) of terrestrial ecosystems. The process -based biome biogeochemical cycles (Biome-BGC) model is widely used for simulating carbon and water fluxes of forest ecosystems. However, the lack of the interaction information of climate, vegetation and soil, such as the hysteresis effect, canopy stratification on photosynthesis, impedes better simulations of the ecohydrological processes. Here, we tended to improve the simulation accuracy of Biome-BGC model at a subtropical forest on the Xin'an River in Southeastern China by reconstructing the precipitation series, modifying the ET and canopy multilayers modules, and optimizing the parameters. The spatiotemporal patterns of GPP, ET, water use efficiency (WUE) and their response to environmental factors across the Xin'an River Basin from 1982 to 2018 were further explored. The results showed that the improved model performed well, with the determination coefficient, root means square error and mean absolute error being 0.730, 1.522 gC/m2/d and 1.218 gC/m2/d for GPP, 0.857, 1.082 mm/d and 0.838 mm/d for ET, respectively. Basin -averaged GPP, ET and WUE increased during 1982-2018 and these increasing trends were more pronounced during 1999-2018. Significant positive trends of WUE occurred in the northeast corner. The increasing air temperature and precipitation respectively dominated the increase in GPP and ET, the increasing CO2 concentration and NDVI mitigated the negative effect of extreme precipitation on WUE. Given that human activities such as afforestation have effectively reduced the extent of damage to forest ecosystems from extreme precipitation, we highlight an urgent need to formulate adaptation strategies aimed at reducing the risk of extreme climate in humid regions.

Reducing fertilizer input is a goal for helping greenhouse farming to achieve higher sustainability in the production process while preserving overall crop performance and quality. Wild rocket plants were cultivated in a plastic greenhouse divided into two independent sectors, one for soil-bound (SbS) cultivation and another equipped for soilless (ScS) cultivation systems. In both SbS and ScS, the crop was subjected to treatments consisting of a high- and a low-input fertilization program (HF and LF treatment, respectively). Water use efficiency (WUE) and partial factor productivity (PFP) for nutrients (N, P, K, Ca, and Mg for ScS, and N for SbS) were measured. Rocket leaves, separated for the cultivation system and fertilization program and collected at different cuts during the growing cycle, were cold stored at 10 degrees C until 16 d. On each sampling day (at harvest and during storage), the sensory parameters, respiration rate, dry matter, color, electrolyte leakage, antioxidant activity, total phenols, total chlorophyll and ammonia content were evaluated. In ScS, the PFP for all nutrients supplied as fertilizers showed a significant increase with the LF treatment, with values higher than 30% recorded for N, K, and Ca. As for the postharvest performance, rocket leaves cultivated in ScS showed better qualitative traits than those cultivated in SbS, as suggested by the lower values of ammonia content and electrolyte leakage recorded at the end of storage period in samples grown in ScS. Moreover, in ScS, the data showed lower membrane damage in LF than HF rocket leaves. Finally, regarding total chlorophyll content, even if no effect of each treatment was recorded in SbS, rocket cultivated in ScS showed a better retention of this parameter by applying LF rather than HF treatment. In addition to this, a PLS model (R-2 = 0.7) able to predict the cultivation system, using as a variable non-destructively measured total chlorophyll content, was implemented. Low fertilization input, both in SbS and in ScS, allowed satisfying production levels and more sustainable management of nutrients. LF treatment applied to ScS also had in positive effects on the postharvest quality of fresh-cut rocket leaves.

Understanding the carbon-water coupling over permafrost regions is essential to projecting global ecosystem carbon sequestration and water dynamics. Ecosystem water use efficiency (EWUE), defined as the ratio of gross primary productivity (GPP) and evapotranspiration (ET), reflects plant acclimation strategies with varying ecosystem functioning against environmental stress. Yet EWUE change and its potential drivers across the northern permafrost regions remain poorly quantified, hampering our understanding of permafrost carbon-climatefeedback. Here, we compared and analyzed the difference using satellite observations and process based models to estimate the spatio-temporal variations of EWUE in 1982-2018 over northern permafrost regions. Using flux measurements as truth data, satellite-derived EWUE was more reliable than model-based EWUE. Satellite-derived EWUE showed biome-dependent spatial patterns, with a steady temporal trend (0.01 g C mm-1 decade-1, P > 0.05) for spatially averaged EWUE over northern permafrost regions. Carbon dioxide (CO2) concentration and nitrogen deposition positively affected interannual variations of EWUE, while vapor pressure deficit and other climatic factors (i.e., temperature, precipitation, and radiation) negatively controlled EWUE. Compared to satellite-derived EWUE, we found that EWUEs derived from an ensemble of process-based carbon cycle models are overestimated in seven out of ten models, with an increasing trend of 0.11 g C mm-1 decade 1 (P < 0.001) for spatially averaged EWUE of the ensemble mean. The relationships between climatic factors and EWUE are partially misinterpreted in model estimates, especially with overstated CO2 sensitivity and the opposite temperature effect. The fluctuating sensitivities to climate over time and the diminishing effect of CO2 fertilization on gross primary productivity (GPP) may partially explain the discrepancy observed between satellite-derived and model-based estimates of EWUE. Thus, this study calls for caution concerning model-based EWUE and aids in understanding permafrost-climate feedbacks and projections of carbon and water cycles.