A sand culture pot experiment by using a two-factor completely randomized design was conducted to investigate the growth patterns of Trisetum tibeticum seedlings under nitrogen， phosphorus， potassium deficiency， and water shortage conditions. The experiment included four nutrient treatments： complete nutrition （CN）， nitrogen deficiency （ND）， phosphorus deficiency （PD）， and potassium deficiency （KD）. And four water treatments： 80% field capacity （W₁）， 60% field capacity （W₂）， 40% field capacity （W₃）， and 20% field capacity （W₄）. The results showed that plants of ND treatment exhibited stunted growth with withered leaves， leaves of PD treatment appeared dark green， and leaves of KD treatment showed yellowing and curling at the tips. Water shortage reduced plant height， and growth rates of ND and PD treatments showed declining trends after three weeks. Nutrient-water interactions significantly influenced leaf length， leaf width， root length， root surface area， root volume， above-ground and below-ground biomass， and root-to-shoot ratio （P<0.05）. Under different water conditions， ND treatment consistently resulted in the shortest leaf length， while CN treatment exhibited the greatest leaf width. Water shortage promoted root development in CN treatment， with the largest root surface area and root volume observed at W₄. ND and PD treatments increased the root-to-shoot ratio， with biomass allocation shifting towards below ground parts， while KD had no significant effect on the root-to-shoot ratio. Therefore， the interaction between water shortage and nutrient deficiency synergistically inhibits the growth of Trisetum tibeticum. In seedling cultivation of Trisetum tibeticum， enhanced growth monitoring and timely targeted supplementation should be implemented.

The aim of this study was to screen low phosphorus-tolerant oat （Avena sativa L.） varieties and to investigate their morphophysiological response mechanisms. Thirty oat varieties were used as materials， and two treatments of normal phosphorus （1000 μmol·L^-1 KH₂PO₄， CK） and low phosphorus （10 μmol·L^-1 KH₂PO₄， LP） were set up by hydroponics. Morphological and physiological indexes were measured after 21 days， and principal components， subordinate functions， and cluster analyses were used for the comprehensive evaluation. The results showed that low phosphorus stress significantly inhibited the aboveground growth of most oat seedlings， but promoted root development. Physiologically， low phosphorus treatment led to a decrease in phosphorus uptake and a significant increase in phosphorus utilization efficiency in most seedlings； soluble sugar content， acid phosphatase and nitrate reductase activities generally increased. Through systematic evaluation， ‘Weidu You No.5’ （D=0.818） and ‘Jin Yan No. 17’ （D=0.643） were identified as the most low-phosphorus-tolerant varieties， whereas ‘Ba You No. 18’ （D=0.341） and ‘Jun Ma’ （D=0.366） were the most sensitive ones. The results of this study provide a theoretical basis and material foundation for the selection and breeding of low phosphorus tolerant oat varieties.

To investigate the responses of forage growth and grassland soil nutrients to nitrogen fertilizer application， and to promote forage yield enhancement and soil nutrient balance， this study conducted a meta-analysis of 62 selected publications comprising 629 valid data sets. The analysis examined the effects of nitrogen fertilizer application on forage growth and soil nutrients under varying meteorological conditions （climatic zones， mean annual rainfall and mean annual temperature）， soil conditions （alkali-hydrolyzable nitrogen （AN）， total nitrogen （TN）， and organic matter （OM））， as well as the amount of nitrogen fertilizer applied （low， medium， and high）. The results indicated that nitrogen fertilizer application significantly enhanced forage growth and improved soil nutrient status. Specifically， forage height and dry matter yield increased by 25.7% and 58.4%， respectively， while soil TN， AN， and OM contents increased by 21.8%， 19.3%， and 9.0%， respectively. Nitrogen fertilizer application in wet， low-temperature regions most effectively promoted forage growth， whereas nitrogen fertilizer application in wet， high-temperature regions was more conducive to enhancing soil nutrient availability. Nitrogen fertilizer application to nutrient-poor grasslands resulted in a more pronounced increase in forage dry matter yield， and even low rates of N addition produced substantial benefits. Our results demonstrate that nitrogen fertilizer addition exerts positive effects on both forage productivity and soil fertility， providing a scientific basis for grassland fertilization decision-making.

In order to explore the effects of alkaline salt stress on the ascorbic acid-glutathione cycle（AsA-GSH） of mitochondria in the radicle and plumule of Bothriochloa ischaemum， this experiment used ‘Taihang’ Bothriochloa ischaemum as material， which was germinated in NaHCO₃ and Na₂CO₃ solutions with Na⁺ concentration of 0（CK）， 10 and 30 mmol·L^-1， and then changes in the activities of AsA-GSH enzymes and lipid peroxidation in their mitochondria of radicle and plumule were analyzed. The results showed that the activities of superoxide dismutase， catalase， glutathione peroxidase and monodehydroascorbate reductase in the mitochondria of radicle increased with the increase of Na⁺ concentration （0-30 mmol·L^-1）， but the opposite phenomenon was observed in the activities of glutathione sulfur transferase， ascorbate peroxidase and glutathione reductase. With the increase of Na⁺ concentration （0-30 mmol·L^-1）， the activities of superoxide dismutase， catalase and glutathione peroxidase in the mitochondria of plumule increased significantly （P<0.05）， but the activities of glutathione sulfur transferase， glutathione reductase and monodehydroascorbate reductase decreased significantly （P<0.05）. There were differences in the effects of type and concentration under alkaline salt on the AsA-GSH in radicle and plumule of Bothriochloa ischaemum， and the sensitivity of mitochondrial AsA-GSH in radicle of Bothriochloa ischaemum to alkaline salt stress was higher than that in plumule.

To evaluate the differences in salt tolerance among different alfalfa （Medicago sativa L.） cultivarsunder salt stress conditions and screen high-quality salt-tolerant germplasm resources，this study used 25 alfalfa cultivars as experimental materials， with two treatments of salt stress （200 mmol·L^-1 NaCl solution）and control （ultrapure water）. Germination and growth parameters were measured during the germination period （eight indicators， such as germination energy and germination rate， etc.） and seedling stage （six indicators， such as plant height and branch number， etc.）， and a comprehensive evaluation of salt tolerance was conducted using methods such as membership function value， comprehensive salt tolerance （D value）， and cluster analyses. The results showed that salt stress significantly reduced all germination parameters， with the seed vigor index exhibiting the highest reduction rate （-92.26%）， whereas the seedling dry weight was the least affected （-11.76%）. Cluster analysis classified the 25 alfalfa cultivars into five salt tolerance grades at the germination stage： included 2 of the strongest salt-tolerant cultivars， 4 strong salt-tolerant cultivars， 5 moderate salt-tolerant cultivars， 10 weak salt-resistance cultivars， and 4 salt-sensitive cultivars. Further evaluation of salt tolerance of 12 representative alfalfa cultivars during the seedling stage revealed salt stress had extremely significant effects on the plant height， above-ground fresh weight， relative water content， and electrical conductivity of alfalfa （P<0.01）， with significant differences between cultivars. By integrating the indicators of both germination and seedling stages， the three strongest salt-tolerant cultivars， namely ‘Xinmu No.4’‘Zhongmu No.4’， and ‘Bara520YQ’， were ultimately selected as important germplasm resources for salt-tolerant breeding and cultivation in saline-alkali soil regions.

To evaluate the effects of intercropping arrangements on phosphorus use efficiency and interspecific competition in legume-grass mixtures， same-row intercropping （T） and alternate-row intercropping （Y） was conducted by the pot experiment. The study investigated the relationships among phosphorus use efficiency （PUE）， interspecific competition， and the overyielding effect in triticale-hairy vetch and triticale-common vetch systems. The results showed that for the triticale-hairy vetch mixture， yield and overyielding were higher in the same-row arrangement， whereas the triticale-common vetch mixture was the opposite. The relative yield （RY） was higher in the alternate-row arrangement for both systems. Metrics including encroachment rate （A）， competition rate （CR）， and relative crowding rate （K） indicated that triticale was the competitively dominant species. Phosphorus use efficiency varied in the triticale-hairy vetch system， and it was higher for triticale under alternate-row but higher for hairy vetch under same-row intercropping； in the triticale-common vetch system， both species showed higher PUE in the alternate-row arrangement. Threshold analysis revealed that highly competitive ability coupled with high PUE synergistically induced the overyielding effect under the alternate-row arrangement. In conclusion， for establishing annual forages in the cool region of Zhaosu， the alternate-row intercropping of triticale and common vetch is recommended.

To identify the SWEET genes in Avena sativa and its responses to drought and salinity-alkalinity stress， this study systematically characterized the AsSWEET gene family using bioinformatics approaches and analyzed their expression patterns under drought and salt-alkali stress conditions by RT-qPCR. A total of 37 AsSWEET genes were identified and mapped to 19 chromosomes. All AsSWEET proteins contained the conserved MtN3_saliva domain， most members possessed seven transmembrane helices （TMHs）， and subcellular localization prediction indicated that they were primarily located on the plasma membrane. Phylogenetic analysis revealed that AsSWEET proteins could be classified into four major clades and shared high homology with SWEET proteins from Hordeum vulgare. Promoter analysis showed that AsSWEET family members harbored numerous cis-acting elements associated with light responsiveness， hormone signaling， development， and abiotic stress responses. Expression profiling indicated that 10， 7 and 18 AsSWEETs genes were significantly upregulated in leaves under drought， salt and alkali stress， respectively. Among them， AsSWEET15a and AsSWEET15c exhibited consistently high expression levels across all stress conditions， suggesting that they might serve as key candidate genes involved in oat tolerance to drought and salt-alkali stress. These findings provide theoretical insights into the functional roles of the AsSWEET gene family in abiotic stress responses and offer potential gene resources for molecular breeding of stress-tolerant oat varieties.

Grasslands play a vital role in safeguarding ecological security and sustaining ecosystem functions. Xinjiang hosts some of China’s most abundant grassland resources. However， under the combined impacts of climate change and human activities， grassland degradation has become increasingly prominent in recent years. To comprehensively assess the current status and degree of ecological restoration in the Xinjiang “Grazing Withdrawal and Grassland Restoration” project areas， we evaluated ecosystem structure， ecosystem quality， and ecosystem services by integrating the InVEST and RUSLE models to quantify restoration outcomes. The results show that： （1） In terms of ecosystem quality， net primary productivity （NPP） increased from 190.96 g·m^-2·a^-1 in 2003 to 205.34 g·m^-2·a^-1 in 2021， and fractional vegetation cover （FVC） continued to rise， with improving areas accounting for 69.78% of the total areas. （2） Regarding ecosystem services， water conservation increased from 98.2 mm during 2003-2015 to 121.1 mm during 2015-2021. Soil retention increased from 273.74 to 283.61 t·hm^-2， while windbreak and sand-fixation capacity changed from 2.82 to 3.62 t·hm^-2. （3） The ecological restoration index （ERI） indicated that high-restoration areas （ERI>0.5） accounted for 19.08% of the study areas， whereas low-restoration areas （ERI≤0.2） represented only 0.02%. These findings provide quantitative evidence to support ecological protection and management in the project areas， facilitating zoned， graded， and differentiated ecological restoration strategies.

Drought is one of the primary stress factors affecting plant production， and the germination stage is the most vulnerable period in the plant life cycle. In the breeding of drought-resistant Bromus inermis， evaluating drought tolerance during the germination stage is particularly important. This study employed the double-layer filter paper germination method， measuring eight indicators-including germination rate， germination potential， germination index， root length， and shoot length-under 25% PEG-6000 stress for 100 B. inermis germplasm resources. Principal component analysis， membership functions， and hierarchical clustering analysis were used to comprehensively assess drought tolerance during the germination stage. The results showed that， compared to the control， all observed indicators decreased under 25% PEG stress， with coefficient of variation ranging from 20.853% to 97.876%. There was a significant correlation （P<0.05） among most experimental indicators. There were substantial differences in drought tolerance among materials， with the comprehensive drought tolerance coefficient ranging from 0.612 to 0.169 and the D-value ranging from 0.861 to 0.068. Cluster analysis classified the 100 t100 Bromus inermis germplasm resources into four groups： highly drought-resistant （14 materials）， moderately drought-resistant （34 materials）， weakly drought-resistant （45 materials）， and drought-sensitive （7 materials）. This study identified drought-resistant germplasm such as W1Z622， W1Z627， and W1Z595. The research provides high-quality materials and theoretical support for drought-resistant breeding of B. inermis.

To investigate the effects of grazing and topography on alpine shrub populations， in this study the effects of topography and grazing on population growth， inter-species relationships in alpine scrub in the Qilian Mountains were analyzed by using the populations of Potentilla anserina and Poa subfastigiata as the research objects， through setting up three kinds of terrain， namely， valley， shady slopes， and sunny slopes and five different distances from livestock pens for each terrain type as grazing plots. The results showed that grazing and topography jointly regulated the growth of two plant populations. The increase in grazing pressure gradient （reduced distance from the livestock pens） inhibited the vertical （plant height） and horizontal （crown width） growth of the two species， and increased the population density and vegetation cover. The valley was characterized by a balance of water and heat resources， and the two species coexisted in the highest density， with shady slope has better humidity conditions and stable water supply， which was conducive to the growth and reproduction of moisture-loving Potentilla anserina. The sunny slope had ample sunlight and suitable thermal conditions， favoring the dominance of Poa subfastigiata in their ecological niche. The topography indirectly influenced the competition of the populations by altering the heterogeneity of microhabitats， while grazing directly influenced the competition through trampling. Topography indirectly affected population competition by altering microhabitat heterogeneity， grazing directly affects population dynamics through trampling and foraging. Topography and grazing influenced the competitive landscape of moisture-loving and drought-tolerant species， thereby affecting their status in the community. This study quantified the pathways of topography and grazing on the growth and interspecific relationships of alpine shrub populations， which can provide a scientific basis for the sustainable utilization of the alpine ecological barriers.