To investigate the long-term ecological impacts of photovoltaic （PV） power stations in desert steppe ecosystems， this study was conducted at the Lingwu PV facility in Ningxia， China. We compared plant communities and soil characteristics across different microhabitats within the solar array over restoration periods of 1 and 5 years. The results indicated that the PV array created highly heterogeneous microhabitats by altering the distribution of light and heat， which significantly influenced the vegetation restoration process. A clear spatiotemporal differentiation in community succession was observed. In the initial restoration stage， pioneer species such as Salsola ruthenica were dominant. After five years， the community gradually transitioned to a stable state dominated by perennial herbs， including Ceratoides latens. Notably， in the shaded areas under the PV panels， strong environmental filtering intensified competition among shade- and drought-tolerant species. This led to a significant decrease in plant diversity indices after five years， although species richness remained high. Structural equation modeling （SEM） revealed that the restoration period is the primary driver of community succession. Microhabitat heterogeneity guides the direction of this succession by regulating soil resources， such as the availability of nitrogen and potassium. This study proposes an ecological restoration pathway for PV sites defined by “environmental filtering-resource competition-stability maintenance”， providing a scientific basis for the ecological restoration and sustainable management of PV power stations in arid regions.

The stability and applicability of reference genes in alfalfa vary significantly depending on the cultivar， growth and development stages， and environmental conditions. In this study， alfalfa （Medicago sativa L.） cultivar ‘Gongnong No.1’ was used as material， and eight candidate reference genes， glyceraldehyde-3-phosphate dehydrogenase GAPDH， ubiquitin protein ligase 2a UBL-2a， Retention in Endoplasmic Reticulum Rer1， eukaryotic elongation factor-1 alpha eEF-1α， actin-depolymerizing factor ADF， ubiquitin carrier protein UBC， tubulin beta-1 chain TUB， and Actin were selected to evaluate their expression stability of different tissues in seedling and adult plant， as well as under waterlogging stress. The analysis employed quantitative real-time PCR （qRT-PCR） and four softwares， including geNorm， NormFinder， BestKeeper， and RefFinder. The results showed that， at the seedling stage， Rer1， Actin， and UBC were the most stable reference genes. At the tissue level， the most stable reference genes for leaves， stems， and roots were Actin， Rer1， and GAPDH， respectively. At the adult stage， ADF， Actin， and TUB exhibited the highest stability， while the most stable reference genes for leaves， stems， roots， and flowers were eEF-1α， Rer1， Actin， and UBL-2a， respectively. Under waterlogging stress， the three most stable reference genes in seedling leaves were TUB， ADF， and eEF-1α， whereas in seedling roots they were ADF， UBL-2a， and Rer1. In the adult stage， the most stable genes were ADF， Actin， and TUB in leaves， and UBL-2a， UBC， and ADF in roots. Overall， Rer1 and UBL-2a are recommended as reference genes for studies of tissue-specific expression， as their stability was less affected by developmental stage or tissue type. ADF and TUB are suitable reference genes for studies involving waterlogging stress.

Small heat shock proteins （Small heat shock proteins， sHSPs） are a class of stress-induced proteins widely present in plants， play crucial roles in plant growth， development， and response to drought and salt stresses. To investigate the function of the MsHSP18.2 gene in Medicago sativa， bioinformatics tools were employed to predict and analyze its theoretical properties， structure， and function. Plants were treated with methyl jasmonate （MeJA）， salicylic acid （SA）， abscisic acid （ABA）， indole-3-acetic acid （IAA）， gibberellin （GA）， and cytokinin （6-BA）， as well as subjected to drought and salt stress. Gene expression levels were analyzed by qRT-PCR at 0， 0.5， 1， 3， 6， 9， and 12 hours post-treatment. Transcriptional autoactivation was examined by using a yeast expression system. The stress resistance function was verified using a heterologous yeast system. The results showed that this protein has a molecular weight of 18.18 KDa and a theoretical isoelectric point of 5.55， exhibiting relatively high instability （instability index： 54.67）. Its secondary structure was predominantly composed of random coils. Expression analysis demonstrated that MsHSP18.2 was upregulated under drought and salt stress treatments and displayed differential responses to various plant hormones. Yeast autoactivation assays confirmed its autoactivation activity. Heterologous overexpression of MsHSP18.2 gene significantly enhanced the salt tolerance （NaCl） and osmotic stress （PEG） tolerance of yeast cells.

The medicinal plant Delphinium albocoeruleum is rich in diterpenoid alkaloids， and possesses significant medicinal and ecological values. However， studies on the characteristics of its chloroplast genome and systematic taxonomic status still remain scarce. In this study， the complete chloroplast genome of this species was sequenced and characterized for the first time， and comparative analyses within Delphinium and related taxa were also conducted. The results indicated that the chloroplast genome of D. albocoeruleum had a total length of 154 258 bp， and exhibited a typical quadripartite structure， including a large single copy （LSC） region of 84 847 bp， a small single copy （SSC） region of 16 301 bp， and an inverted repeat （IR） region of 26 555 bp. The total GC content was 38.25%. A total of 131 genes were annotated， including a unique ycf1 pseudogene， which presented a boundary differentiation pattern characterized by truncation at the IRb/SSC boundary and intact function at the SSC/IRa boundary. We identified 243 simple sequence repeats （SSR） loci， with 67.1% of these SSR loci concentrated in the LSC region and A/T mononucleotide repeats being the dominant type. Furthermore， seven positive selection genes （e.g.， matK， ndhD） and 15 highly divergent regions （Pi>0.020） were detected， indicating that the genome was overall conserved but local variations. Phylogenetic analysis demonstrated that D. albocoeruleum had the closest genetic relationship with D. candelabrum. These results provide an important basis for research on the phylogeny， genetic evolution， and geographical origin of the tribe Delphineae.

To screen salt-tolerant and growth-promoting bacterial strains adapted to the extreme environment of Southern Xinjiang from the rhizosphere soil of Cyperus esculentus L. and enrich the strain resource bank for saline-alkali sandy soils in Xinjiang， this study employed the targeted screening medium culture method， shake flask culture method， and 16S rDNA identification method to isolate salt-tolerant and growth-promoting strains， determine their growth-promoting characteristics， and finally further verify the growth-promoting effects of these strains through Cyperus esculentus seed germination tests and potted seedling experiments. A total of 10 salt-tolerant and growth-promoting strains were obtained， which belonged to the genera Bacillus， Vreelandella， Exiguobacterium， and Bisbaumannia， with their salt tolerance thresholds ranging from 4% to 8% NaCl. Among these strains， strain Y-38 （Exiguobacterium acetylicum） exhibited prominent inorganic phosphorus-solubilizing ability （0.65 mg·L^-1）， strain Y-35 （Exiguobacterium mexicanum） showed the highest production of indole-3-acetic acid （IAA） （64.35 mg·L^-1）， and strain Y-46 （Bisbaumannia pacifica） could tolerate 8% NaCl. In the seed germination experiment， the germination rate of the Y-38 treatment group reached 82.00%， which was significantly 26.89% higher than the control group （P<0.05）； in the potted experiment， growth indicators of the Y-38 treatment group， including plant height （39.17 cm）， leaf width （5.22 mm）， and stem diameter （5.52 mm）， were all significantly higher than those of the Y-46 and Y-35 treatment groups （P<0.05）. The comprehensive ranking of the growth-promoting effects of the three strains was Y-38>Y-46>Y-35. Ultimately， the high salt tolerance and growth-promoting function of strain Y-38 （Exiguobacterium acetylicum） was confirmed， providing a bacterial strain resources for the improvement of saline-alkali soils.

To screen biocontrol strains with high herbicidal potential， the pathogenic fungus JZ-28 was isolated from naturally infected leaves of Viola philippica in Qinghai Province. Through morphological characterization and multi-gene （ITS， EF-1α， LSU） phylogenetic analysis， the isolate was identified as Clonostachys rosea. Pathogenicity assays demonstrated potent herbicidal activity of strain JZ-28， inducing chlorosis in detached leaves of four dominant broadleaf weed species from the Qinghai-Xizang Plateau（Malva verticillata， Elsholtzia densa， Senecio vulgaris， and Chenopodium album）within 7 days post-inoculation （dpi）. Disease incidence rates in whole-plant assays reached 83%， 95%， 100%， and 70%， respectively. Safety evaluation on six major crops and three cool-season vegetables in Qinghai revealed that JZ-28 was safe for four crops： Zea mays， Vicia faba， Pisum sativum， Brassica napus， and three vegetables： Cucumis sativus， Solanum lycopersicum， and Solanum melongena. Lightly Susceptible was observed in highland barley Hordeum vulgare and Triticum aestivum. These findings indicated JZ-28’s potential as a broad-spectrum bioherbicide against broadleaf weeds in multiple cropping systems. Culture optimization identified sucrose and soybean meal as optimal carbon and nitrogen sources for enhancing mycelial growth and sporulation. This study provided the first evidence of Clonostachys rosea’s bioherbicide potential in alpine ecosystems， addressing a critical research gap in microbial herbicide development and offering sustainable weed management solutions for fragile environments.

To explore the allelopathic mechanism of Euphorbia jolkinii Boiss， a degradation indicator species of mountain meadows in northwest Yunnan， in this study we analyzed its effects on soil phosphorus transformation and related indicators by adding different concentrations of 4-Nitrophenol （4-NP） and 2-Phenethylamine （2-PEA） to the soil. The results showed that both allelochemicals significantly increased soil microbial biomass phosphorus， aluminum-bound phosphorus， calcium-bound phosphorus， and moderately reactive organic phosphorus content， decreased pH and iron-bound phosphorus， occluded phosphorus， moderately stable and highly stable organic phosphorus content （P<0.05）， and promoted the proliferation of bacteria and actinomycetes. 4-NP significantly enhanced phytase activity and reduced acid phosphatase activity. 2-PEA significantly increased acid phosphatase， phytase， and phosphodiesterase activities， while reduced alkaline phosphatase activity （P<0.05）. In summary， the addition of 4-NP and 2-PEA directly affects soil physicochemical properties， changes the content of organic and inorganic phosphorus components， indirectly achieves the accumulation of soil nutrients in its rhizosphere environment， and promotes its further expansion.

The responses of carbon/water cycles in different grassland ecosystems to extreme climatic events and the underlying mechanisms varied. This study， employed the biogeochemical cycle model Biome-BGCMuSo （BGC with Multilayer Soil Module）， integrated with eddy covariance data，conducted sensitivity analysis and parameter optimization to investigate variations in carbon/water fluxes across different grassland types and their responses to extreme climates. The results showed that carbon flux simulations were sensitive to vegetation photosynthetic physiology and carbon allocation parameters， while water flux simulations were sensitive to leaf and root parameters， with variations across grassland types. Optimizing highly sensitive parameters significantly improved carbon flux simulation accuracy， but water flux simulations still require refinement. During growing season heatwaves， all three grassland types remained carbon sinks， though diurnal carbon sequestration decreased by 28.7% and 29.4% in temperate desert steppe and mountain meadows， respectively. Extreme rainfall enhanced carbon and water fluxes across all three grasslands. Drought events increased carbon sequestration by 62.5% in temperate desert steppe but decreased it by 16.3% in mountain meadows. This study reveals distinct response mechanisms of carbon and water cycles in grasslands of arid-semiarid regions to extreme climatic events， providing scientific basis for predicting the evolution of grassland ecological processes under climate change.

Dichondra （Dichondra repens） is a warm-season perennial ground cover plant belonging to the Convolvulaceae， which is widely utilized in landscaping， soil and water conservation， and orchard ground cover. Low-temperature stress is a main limiting factor restricting its promotion and utilization. In this study， we evaluated turf performance and cold adaptability of 12 dichondra genotypes， including nine wild materials which were collected from Southwest China， two nationally certified cultivars， and one widely-used introduced cultivar. The results found significant variations in leaf area， uniformity， leaf color， green period， canopy height， and establishment rate among the 12 genotypes. A comprehensive evaluation of turf performance by using the subordinate function values analysis indicated that the wild Dr5 exhibited superior characteristics including fast establishment， short canopy height， dark green leaf color， high uniformity， and the longest green period， demonstrating high lawnscape value. In contrast， wild Dr17 showed the poorest turf performance. Under consecutive two-year low-temperature stress， all genotypes showed significant declines in chlorophyll content and fluorescence parameters （Fv/Fm and PI_ABS）， but electrolyte leakage and malondialdehyde content exhibited varying degrees of increase. Notably， Dr5 demonstrated the lowest semilethal temperature， lower EL and MDA content， and higher chlorophyll content， Fv/Fm， and PIABS. These findings indicated that Dr5 had significantly lower oxidative damage to cell membrane， enhanced membrane stability， and superior photosynthetic performance under cold stress. Based on a comprehensive evaluation of cold tolerance using the subordinate function values analysis over two years， cold tolerance of 12 genotypes was ranked in descending order as follows： Dr5>Dr21>Dr1>Dr32>Dr2>Dr33>Dr30>Dr3>Dr4>Dr15>Dr11>Dr17. Dr5 exhibited the strongest cold resistance， and Dr17 had the weakest cold tolerance. Given its excellent turf quality and exceptional cold tolerance， Dr5 could be used as a superior germplasm for landscaping and a key candidate for breeding cold-tolerant dichondra cultivars. These findings also lay a foundation for further research into the low-temperature adaptation mechanism of different dichondra genotypes.

The restoration of saline grasslands relies on effective soil amelioration， precise seeding timing， and successful seedling establishment. In this study， the pioneer grass species Leymus secalinus was used as test material， and low， medium， and high salinity levels of salt stress were set up using a 1∶2 ratio of NaCl and Na₂SO₄. The effects of salt stress and its interaction with seedling age on root system phenotypic plasticity were investigated. Our results showed that salt stress made roots grow shallower. Seedling age was the main factor controlling root biomass distribution （P<0.001）. Salt alone and its interaction with age were only significant in some cases. Salt and age both reduced root length， surface area， and volume （P<0.01）. Their interaction had the strongest effect on root volume （F=36.878）. Salt damage increased nonlinearly as the seedling grew. Root tip number decreased with higher salt. Older seedlings were more sensitive to salt. Root angle significantly reduced at the two- and three-leaf stages. Also， root fractal dimension showed a nonlinear response， and increased under low salt but decreased under medium and high salt （P<0.05）. This study revealed the phased adaptation strategies of Leymus secalinus seedlings under salt stress， providing a basis for enhancing the application potential of Leymus secalinus in ecological restoration of saline grasslands.

The identification and characterization of phenotypic traits are the foundation for understanding crop germplasm resources for breeding new cultivars. The sorghum germplasm from Central Asia demonstrated unique genotypes. It is of great significance to fully understand these materials for sorghum breeding in China. This study focused on 44 sorghum germplasm resources introduced from Central Asia. Precise characterization of phenotypic traits was systematically conducted， combined with multivariate statistical methods （including correlation analysis， cluster analysis， and principal component analysis） for systematic evaluation. Data analysis revealed that the tested accessions exhibited high heterogeneity at the phenotypic level， possessed diverse genetic backgrounds， and demonstrated complex interrelationships among traits. Cluster analysis grouped the 44 sorghum accessions into five clusters. Based on different breeding objectives， suitable germplasm resources can be selected. Principal component analysis （PCA） and comprehensive evaluation were performed on the sorghum resources. Based on F-values， the top 10 accessions with the best overall performance were identified. Among them， 7 germplasm materials belonged to Cluster II， and their phenotypic characteristics were significantly superior to that of the other clusters （e.g.， with mean plant height reaching 286.33 cm and panicle weight at 102.50 g）. They showed particularly outstanding performance in stalk lodging resistance and grain yield potential， making them valuable core parental materials for germplasm innovation and the development of hybrid combinations. This study analyzed the phenotypic diversity of sorghum germplasm resources and classified them based on similar phenotypes. This study provides a theoretical foundation for sorghum cultivation in semi-arid and arid regions， and also lays a foundation for the efficient utilization of sorghum germplasm resources and the development of new varieties.

Though the Loess Plateau dryland region in northern Shanxi is a key oat-producing area in China， its forage productivity remains low due to limited rainfall and a lack of suitable oat varieties. To identify high-quality， high-yield forage oat （Avena sativa） cultivars， we evaluated 38 widely promoted domestic and imported varieties， assessing their growth periods， agronomic traits， yields， and nutritional quality. The results showed that there was significant variation in maturity time （86-127 days）， with late-maturing types predominating （21/38）. ‘Molasses’ and ‘Tianyan No.3’ achieved the highest fresh （27 100 and 23 500 kg·hm^-2） and dry forage yields （11 700 and 11 500 kg·hm^-2）. Five cultivars-including ‘Magnum’-had the highest soluble sugar content （16.4%-18.1%）， while ‘Shooter’‘Longyan No.2’ and ‘Longyan No.1’ had the greatest crude protein content （8.7%-8.8%）. Seventeen varieties exhibited premium forage quality， with Relative Forage Value values of 113.7-126.1. Based on the “Quality Classification of Oat Hay” standard， 13 cultivars were classified as Type A hay and 9 as Type B （all Grade III）. Overall， ‘Molasses’ ‘Magnum’ ‘Tianyan No.3’ ‘Jiayan No.2，’ and ‘Monida’ demonstrated superior performance and are recommended for priority adoption in eastern dryland areas of northern Shanxi’s Loess Plateau.

To explore the influence of urban grassland types on soil DOC and its characteristics， this study took the urban green space ecosystem in Beijing as research object. Four treatments were established： bare land， cool-season grassland， warm-season grassland， and urban understory ground cover. The soil DOC content was measured， and the spectral characteristics of soil dissolved organic matter （DOM） were analyzed by using ultraviolet-visible spectroscopy and three-dimensional fluorescence spectroscopy. The results showed that compared to the bare land， the DOC content of the cool-season grassland surface soil was significantly decreased by 30% （P<0.05）， but there was no significant difference from warm-season grassland and urban understory ground. The UV spectra showed there was no significant difference between the aromaticity and the hydrophobicity of the DOM among the treatments. The fluorescence spectra showed that the DOM of urban grasslands had mixed source characteristics. In compared with the bare land， the humization process of the urban grasslands was enhanced but self-source contribution was decreased， with strong microbial activity but weak bio-availability. The results showed that the dynamic of DOC in urban grassland was regulated by vegetation type， management measures and microbial activity. The optimization of fertilization management and the consideration of carbon sequestration type of grass species could enhance the function and stability of urban soil carbon sequestration， which provided theoretical support for the improvement of urban green space ecological function.

In this study， we used S. transiliense seedlings as a research object and conducted a pot experiment with continuous drought stress to systematically investigate the dynamic changes in root system morphology， physiological response and anatomical structure. The results showed that with the increass of drought stress intensity， root system morphology changed significantly， with a decrease in topological index and fractal dimension， and a shift in root branching patterns towards a more efficient “dendritic” structure. At the physiological level， there was a significant accumulation of reactive oxygen species （ROS）， increase in membrane lipid peroxidation and enhanced ability to regulate osmosis. Antioxidant enzyme activity showed a trend of increasing first and then decreasing. The anatomical structure analysis revealed that the root tip epidermal and endodermal cells thickened to enhance water-holding capacity， while the cortical parenchyma， vascular system and root tip diameter all showed a decreasing trend to optimize water transport efficiency. This study revealed the adaptive strategy of S. transiliense by integrating root system configuration plasticity， physiological regulation， and anatomical structure optimization， providing a scientific basis for studying the drought resistance mechanisms of desert plants and also offering an important reference for ecological restoration and breeding in arid areas.

The mechanism of the influence of vegetation restoration on soil characteristics in the loess hilly landslide area is unclear， in this study we selected the typical landslide area in the loess hilly and gully region of central Gansu in the upper reaches of the Yellow River as the experimental site. Through field sampling and indoor analysis， combined with fractal theory， the differences in soil particle size characteristics and physical and chemical properties under three ecological restoration measures， namely natural restoration， honeysuckle planting， and corn planting， were compared. The results showed that： （1） Under different ecological restoration measures， the composition of soil particles was mainly composed of sand grains （34%~37%）， fine sand grains （27%-28%）. （2） Compared with natural restoration， the pH in the honeysuckle area decreased significantly， and the moisture content in the corn area increased significantly. The contents of soil organic matter， total nitrogen and total phosphorus in artificial restoration were all higher than those in natural restoration. （3） The range of the single fractal dimension was 2.44 to 2.72， specifically corn （2.72）> honeysuckle （2.65）> natural recovery （2.44）， and the recovery of corn leads to better soil quality. Under different ecological restorations， the single fractal dimension of soil showed an increasing trend as the soil texture changes from coarse to fine. The nutrient content and moisture content of soil restored artificially were higher than those restored naturally， that was， artificial restoration measures were more conducive to enhancing the soil's water retention capacity and nutrient fixation capacity. The study shows that in the process of landslide control， appropriately adopting auxiliary measures of artificial restoration can effectively improve soil structure， increase vegetation coverage of the landslide site， and reduce soil erosion.

To investigate the response mechanism of terpenoid root exudates to salt stress in halophytes， Elytrigia elongata was used as a model species. Gradients of NaCl solutions were applied to soil to simulate control， light， moderate， and severe salt stress conditions. A non-targeted metabolomics approach was employed to identify the profiles and relative abundances of terpenoid compounds in root exudates， and correlations between terpenoid abundance， root morphological traits， and rhizosphere soil physicochemical properties were analyzed. The results showed that compared with the control， the relative abundance of sesquiterpenes， monoterpenes， diterpenes and other terpenoids in root exudates significantly decreased by 8.61%-16.41% under light， moderate and severe salt stress treatments. Triterpenoids and triterpene saponins significantly decreased by 24.54% and 12.43% respectively only under light salt stress. Soil pH emerged as the primary factor influencing terpenoid exudation in Elytrigia elongata. As soil salinity increased， pH decreased， thereby suppressing the secretion of sesquiterpenoids， monoterpenoids， diterpenoids， and other terpenoid classes. These findings provide critical insights into the physiological mechanisms underlying plant adaptation to saline environments.

Grass mulching has been proven to effectively enhance soil organic carbon accumulation and improve soil fertility in orchard systems. However， the mechanisms regulating the dynamics of labile organic carbon and humified carbon fractions remain unclear. From 2021 to 2023， a field experiment was conducted in an apple orchard with four grass mulching treatments established in both interrow and tree disk areas： perennial ryegrass （Lolium perenne L.）， sweet clover （Melilotus officinalis L.）， perennial ryegrass + alfalfa （Medicago sativa L.）， with traditional clean tillage as the control （CT）. We analyzed soil labile organic carbon fractions， humic carbon fractions， carbon-cycling enzyme activities， and the carbon pool management index. The results showed that sweet clover significantly increased soil organic carbon content by 14.38% and elevated the carbon pool management index by 89.55% in the interrow area compared to CT in 2022 （P<0.05）. In 2023， sweet clover further reduced soil pH in the interrow areas and the bulk density of the tree disk areas. Meanwhile， the perennial ryegrass + alfalfa mixture treatment increased soil organic carbon by 19.19% in the tree disk area， with concurrent rises in dissolved organic carbon and microbial biomass carbon （P<0.05）. Mantel tests and partial least squares path modeling revealed distinct responses of the interrow and tree disk areas to grass mulching. Increased labile organic carbon fractions primarily characterized the interrow areas， while the tree disk areas showed a strong positive response in humified carbon accumulation. In conclusion， sweet clover performed the best in interrow areas， while the perennial ryegrass + alfalfa mixture was the most effective in tree disk zones. Grass mulching in apple orchards can positively regulate the soil carbon pool through improvements in soil physical structure， activate carbon-cycling enzymes， and increase soil carbon fractions.

Drought and phosphorus deficiency are key factors limiting oat （Avena sativa） production in the Qinghai-Tibet Plateau. In order to elucidate the effects of water and phosphorus stress on oat growth， identify the primary limiting factors， and screen for key indicators of oats’ synergistic adaptation to water and phosphorus constraints. This study utilized 14 oat cultivars in pot experiments， with treatments including a control （CK）， low phosphorus stress （-P）， drought stress （-W）， and combined drought and low phosphorus stress （-W-P）. Additionally， this experiment measured 18 indicators， including agronomic traits， biomass， and phosphorus accumulation， among others. Results indicated that stress treatment significantly suppressed oat aboveground biomass and biomass of individual aboveground organs， spikelet number， grain per spike， and phosphorus accumulation at the 0.05 level. Moreover， the degree of inhibition is greater under combined stress than under single stress. Different indicators exhibited varying degrees of susceptibility to each factor， with water availability being the primary growth-limiting factor. Methods such as grey relational analysis and principal component analysis jointly identified grain biomass， aboveground biomass， spikelet number， grain per spike， belowground biomass， flag leaf area， and phosphorus accumulation in plants and grains as key indicators reflecting oats' tolerance to water and phosphorus stress. The findings of this study provide theoretical foundations and methodological guidance for the breeding and evaluation of drought-tolerant and low-phosphorus-tolerant oat cultivars on the Qinghai-Tibet Plateau.

Grassland ecological governance is a critical measure for ensuring ecological security and promoting the sustainable development of pastoral areas. Based on the theory of social embeddedness， this study utilizes survey data from 410 herder households in Inner Mongolia constructed a five-dimensional framework comprising policy， cognitive， cultural， structural， and relational embeddedness， empirically analyzed the mechanisms influencing herders’ willingness to participate in grassland ecological governance and their willingness to pay （WTP）. The findings indicated that cognition and relationship embedding positively affected the willingness to participate， while cultural embedding exerted a significantly negative effect. Conversely， the WTP was driven positively by cognitive and relationship embedding alone. Furthermore， the ISM model revealed that resource endowments-including years of experience in animal husbandry， total number of family members， grassland contract area， and livestock inventory-constitute the underlying root factors. Their influence was channeled through the key mediating variables of awareness of governance policies and expenditure on forage， which subsequently indirectly affected socially embedded factors such as the perception of policy impacts， recognition of governance necessity， and perceived attitudes of peers. This pathway ultimately shapes both the willingness to engage in neighborhood cooperation and the overall willingness of herders. Heterogeneity analysis showed that the effects of social embeddedness factors varied significantly across different grassland types. It was recommended to implement differentiated policies based on grassland types， enhance economic compensation， strengthen policy communication and community atmosphere building， and effectively leverage social norms to boost herders’ participation motivation.

This study focused on the wetland ecosystem of the Black-necked Crane National Nature Reserve in the Lhasa River Basin， systematically explores the niche characteristics， interspecific associations， and community stability of the dominant populations in the shrub layer and herb layer， analyzes the survival strategies， resource competition， and symbiotic relationships of dominant species in the alpine wetland environment， aiming to promote the positive associations between dominant species and companion species and optimize the community structure； The results show that： the average value of the Levins index in the herb layer （7.97） is higher than that in the shrub layer （3.27）， and the average value of the Shannon index （2.03） is also higher than that in the shrub layer （1.20）， indicating that herbaceous plants have better breadth and uniformity of resource utilization. The niche overlap index shows that the average value in the herb layer （0.22） is higher than that in the shrub layer （0.18）， with more intense resource competition. The interspecific association analysis shows that the shrub-herb layer presents a positive association as a whole （all VR values are greater than 1）. The overall symbiosis of plants in the shrub layer is stronger than competition， while the resource competition among species in the herb layer is more intense than that in the shrub layer. The community stability model shows that the Euclidean distances between the shrub layer， the herb layer and the theoretical stable point （20， 80） are 7.98 and 22.77 respectively， and the herb layer is in an unstable state. The study suggests optimizing vegetation configuration by screening species with matching ecological habits to enhance community stability， so as to provide a theoretical basis for the vegetation management of the reserve and the protection of the Qinghai-Xizang Plateau ecosystem.

To explore the distribution pattern and influencing factors of plant communities in the desert zone of the Aksu River basin’s landscape engeneering area， this study used field survey results as the research object. The TWINSPAN method was used for quantitative classification of communities， and the CCA （canonical correspondence analysis） method was emplyed to screen significant influencing factors. The structural equation modeling was used to investigate the interactive relationship between the distribution patterns of plant communities and environmental variables. The results showed that the TWINSPAN hierarchical classification classified the 30 survey locations into 6 association types. The Simpson and Shannon-Wiener diversity indices showed that association II and III had the highest values， while association I and V had the lowest. The Mrgalef richness index showed that association II had the highest value， which was significantly higher than association V by 1.02 times （P<0.05）. The Pielou index showed that association IV had the highest value， with relatively uniform distribution. The similarity of each community type was highest between association I and II， with the highest Jaccard’s index and Sorenson’s index values of 0.478 and 0.393. CCA ranking results indicated that the primary environmental factors influencing community distribution patterns were multi-year average precipitation， elevation， soil organic matter， and soil bulk density （P<0.001）. Further analysis of the interaction between environmental factors and association distribution patterns revealed that topographic factors， consisting of elevation and slope， had the greatest influence， with a total effect size of 0.852. These factors significantly influenced meteorological and soil factors such as annual average precipitation， evaporation， and soil organic matter， thereby influencing association spatial distribution patterns. This research provides a scientific theoretical foundation and empirical support for setting ecological restoration targets， vegetation selection， and measurement formulation for the Aksu River Basin landscape engineering project.

Investigating the effects of grazing on the ecological chemometric characteristics of carbon （C）， nitrogen （N）， and phosphorus （P） in the plant-soil continuum of long-term enclosed grasslands is crucial for sustainable grassland management. This study investigated a 38-year-old enclosed grassland in Yunwu Mountain， Ningxia， by systematically analyzing ecological-metabolic ratios and their coupling relationships at the community level （community-weighted average） for leaves and soil across four grazing intensities of Gansu Cervus canadensis （Cervus elaphus kansuensis）： ungrazed， light grazing， moderate grazing， and heavy grazing. Results indicated： （1） Moderate grazing most effectively promoted N and P accumulation. Plant growth shifted from P limitation under no grazing and combined N-P limitation under light/moderate grazing to N limitation under heavy grazing； （2） With increasing grazing intensity， both topsoil soil organic carbon （SOC） and C∶N ratio in the topsoil （0~10 cm） showed an initial increase followed by a decrease， peaking at moderate grazing levels at 40.40 g·kg^-1 and 12.08， respectively. Conversely， soil N， C∶P， and N∶P ratios were the lowest at light grazing levels at 3.22 g·kg^-1， 48.15， and 4.43， respectively. All soil parameters decreased with increasing soil depth. （3） Leaf C and N contents showed negative correlations with most soil SOC， N， P， and their ratios， while leaf P content was correlated positively with these parameters. Soil depth influenced both plant leaf and soil chemical parameters， whereas grazing intensity primarily affected soil-related indicators. In summary， grazing significantly influenced the chemical-nutrient characteristics of the plant-soil system in the long-term enclosed grassland of Yunwu Mountain. Moderate grazing promoted plant growth and soil nutrient accumulation， representing a critical grazing intensity threshold for maintaining regional grassland health. These findings provide data support and theoretical basis for further optimizing grazing management and promoting the sustainable use of long-term closed-pasture grasslands.

To investigate the effects of different composite improvement measures on soil enzyme activities and microbial communities in degraded meadow steppes， this study set up four treatments： root cutting+organic fertilizer+microbial inoculant （YQJ）， root cutting+organic fertilizer （YQ）， root cutting+foliar fertilizer （YY）， and control （CK）. High-throughput sequencing was used to determine the community structure and diversity of soil bacteria and fungi.The results showed that the YQJ treatment had a significant effect on increasing the activities of soil catalase， invertase， urease， and alkaline phosphatase， followed by the YY treatment. The composition of dominant bacterial and fungal species among different composite improvement treatments was basically similar， but the relative abundance of dominant fungal community species varied greatly. The YQJ treatment significantly reduced the relative abundance of Basidiomycota； the YY treatment significantly increased the relative abundance of Ascomycota （P<0.05）. The root cutting+foliar fertilizer treatment significantly increased the Alpha diversity indices of soil bacteria and fungi （P<0.05）. Correlation analysis results showed that soil catalase， urease， and invertase were closely related to changes in the bacterial community； soil urease and aboveground biomass were closely related to changes in the fungal community. In conclusion， composite improvement measures could improve soil enzyme activities and grassland productivity by regulating and improving the structure of soil bacterial and fungal communities， and the root cutting+foliar fertilizer treatment had the best improvement effect.

To clarify the occurrence trends of poisonous weeds in grasslands under future climate change， and to scientifically prevent their spread and reduce economic losses in the livestock industry， this study based on the distribution data of five frequently occurring grassland poisonous weeds in the Ili River Valley： Sophora alopecuroides， Aconitum leucostomum， Xanthium spinosum， Rumex thianschanicus， and Peganum harmala—and combined with 55 influencing factors， employed the Maximum Entropy model to explore the impact of climate change on the occurrence trends of these five grassland poisonous weeds. The results showed that the prediction models for the five grassland poisonous weeds all had an accuracy greater than 0.8， indicating high precision. Under four future climate scenarios， the total potential occurrence area of Aconitum leucostomum decreased， while that of the other four grassland poisonous weeds increased. Under the medium-to-high emission scenario （SSP370）， grassland poisonous weeds were more prone to expansion and posed greater risks. In terms of migration direction， in the future， Aconitum leucostomum， Rumex thianschanicus， and Peganum harmala would mainly migrate southward， Sophora alopecuroides would migrate eastward， and Xanthium spinosum would migrate toward the southeast and northeast， with an overall trend of grassland poisonous weeds migrating toward lower latitudes. Under the four future climate scenarios， the area of overlapping zones for multiple grassland poisonous weed species increased， with the largest overlapping area occurring under the high-emission scenario （SSP585）. In conclusion， continuous increases in carbon emissions will exacerbate the spread and harm of grassland poisonous weeds.

This study aimed to clarify the potential suitable habitats of three Orinus species， including O. thoroldii， O. kokonoricus and O. intermedius， under the background of climate change. Based on the data of species distribution records and climate variables， MaxEnt model and ArcGIS were applied to conduct spatial simulation and prediction of three Orinus species. The results showed that the predictive accuracy was high （AUC>0.95）. The key environmental factor influencing habitat suitability was altitude for O. thoroldii， the mean temperature of the wettest quarter was the main factor for O. kokonoricus， while the mean diurnal temperature range was the key one for O. intermedius. From the Last Interglacial to the Mid-Holocene， the suitable area for O. thoroldii and O. kokonoricus decreased， while that for O. intermedius increased. Under the future climate scenarios， the suitable area of O. thoroldii and O. kokonoricus showed an initial increase followed by a decrease， whereas the opposite trend was observed for O. intermedius. Currently， the high suitable area of O. thoroldii was mainly located in the southwest of the Qinghai-Xizang Plateau， that of O. kokonoricus was in the east of the Qinghai-Xizang Plateau， while that of O. intermedius was in the central part and northeast of the Qinghai-Xizang Plateau. We thought that the high suitable habitat of Orinus species was in the southwest， east， northeast and central parts of the Qinghai-Xizang Plateau. It is suggested to strengthen in situ protection to cope with the pressure brought by future climate change.

Exploring the effects of grazing on ecosystem multifunctionality （EMF） in long-term enclosed grasslands is of great significance for sustainable grassland management. A 4-year grazing experiment with four intensities （control， light， moderate， and heavy） using Cervus elaphus kansuensis was conducted in the long-term enclosed grasslands of Yunwushan， Ningxia. Plant traits， species diversity， functional diversity and 11 grassland functional indicators were measured， and correlation analysis， linear regression and random forest models were employed to investigate the impacts of grazing intensity on grassland EMF.Results showed that compared with heavy grazing， moderate grazing （light and moderate intensities） significantly increased the coverage and density of gramineous and leguminous plants， as well as leaf nitrogen content， Shannon-Wiener index， species richness， Pielou evenness index， functional divergence index， soil total phosphorus content and EMF. Correlation analysis indicated significant positive correlations between EMF and community coverage， density， leaf carbon and nitrogen contents， and multiple diversity indices. Grazing intensity， community structural characteristics， leaf functional traits and species diversity indices were confirmed as important predictors of EMF.In conclusion， EMF in long-term enclosed grasslands is significantly enhanced by moderate grazing through the improvement of community structure， optimization of leaf functional traits and promotion of community species diversity.

To clarify the community structure， distribution pattern of wild vascular plants in wetlands of the National Nature Reserve for Black-necked Cranes in the Lhasa River Basin and their relationship with environmental factors， the study conducted field surveys on 23 typical plots in the reserve from 2022 to 2023， using methods such as TWINSPAN classification， CCA ordination， and diversity index analysis， to systematically investigate community type classification， spatial distribution characteristics， environmental driving mechanisms， and the coupling relationship with black-necked crane habitats. Results showed that a total of 114 species of wild vascular plants belonging to 83 genera and 34 families were recorded in the study area， with dicotyledonous herbs as the main components； TWINSPAN classified the communities into 7 types， among which the communities were mainly composed of herbaceous plants， with fewer arbor plants. CCA ordination indicated that longitude， mean annual precipitation ， slope gradient ， and slope aspect were the key environmental factors driving community distribution. Diversity analysis showed that the Shannon-Wiener index （1.31-2.95） and Simpson index （0.37-0.99） were significantly different among communities （P<0.05）， and the Mantel-test confirmed that mean annual precipitation had the most significant impact on the Pielou evenness index and Shannon-Wiener index . Further quantification by RDA analysis showed that longitude， mean annual precipitation， slope aspect， and slope gradient were the core factors regulating community diversity. Among them， the Shannon-Wiener index and Pielou index were positively correlated with mean annual precipitation， and the Simpson index responded significantly to the longitude gradient. The results revealed the adaptation patterns of plateau wetland plant communities to hydrothermal gradients， providing a theoretical basis for the protection of black-necked crane habitats and wetland ecosystem management.

To reveal the characteristics and spatial differentiation mechanisms of soil fertility at different degradation stages of alpine marsh wetlands， 84 plots were selected in this study， including non-degraded， lightly degraded， and moderately degraded wetlands in Qilian Mountain National Park， Qinghai. An improved Nemerow index and principal component analysis were used to evaluate soil fertility， and the geographical detector model was employed to quantify the influence of environmental factors on its spatial heterogeneity. The results showed that soils at all degradation stages were within the fertile level. The comprehensive fertility index was the highest in non-degraded wetlands （2.03）， slightly decreasing in lightly （1.87） and moderately degraded wetlands （1.83）， with total nitrogen being identified as the main limiting factor. As degradation intensified， soil organic matter， cation exchange capacity， total nitrogen， and total phosphorus gradually decreased， whereas total potassium increased. Except for total potassium， all indicators declined with soil depth. Geographical detection revealed that mean annual precipitation （q=0.741）， altitude （q=0.403）， and mean annual temperature （q=0.402） were the dominant factors influencing the spatial differentiation of soil fertility. Among the multi-factor interactions， the combinations of mean annual precipitation and temperature （q=0.897）， and temperature and NDVI （q=0.870） showed the strongest explanatory power for the spatial pattern of soil fertility. These findings provide a theoretical basis for degradation diagnosis and ecological restoration of alpine marsh wetlands.

The Qaidam Basin is a typical inland arid saline basin in China， characterized by high soil salinity and harsh plant growth conditions. Soil amendment is therefore of great significance for the rational development and utilization of saline-alkali land. This study focused on oat （Avena sativa） grown with the application of four soil amendments （single superphosphate， potassium humate， cattle manure+desulfurized gypsum， and attapulgite） to analyze oat production performance and nutritional quality， aiming to identify the ideal soil amendment for saline-alkali soils in the Qaidam Basin. The results showed that oat treated with single superphosphate achieved greater plant height， stem diameter， and forage yield， measuring 107.57 cm， 3.47 mm， and 1001.00 g·m^-2， respectively. Oat treated with potassium humate exhibited higher crude fat and water-soluble carbohydrate content， at 3.15% and 25.40% respectively， while its acid detergent fiber and neutral detergent fiber content were lower. Piecewise Structural Equation Modeling （SEM） analysis indicated that the soil amendments affected nutritional quality by influencing forage yield and stem diameter. The TOPSIS multi-criteria decision model demonstrated that oat treated with single superphosphate had superior production performance and nutritional quality， which is the ideal soil amendment for application in saline-alkali soils of the Qaidam Basin.

In order to explore the effects of spraying brassinosteroid （BR） on the growth and physiological characteristics of alfalfa （Medicago sativa） seedlings under low temperature stress， the new cold-resistant alfalfa line （P4） and Longdong alfalfa （Medicago sativa ‘Longdong’） were used as the research objects in this study. After 13 days of low temperature stress （4℃）， different concentrations of exogenous BR （0.00， 0.25， 0.50， 0.75， and 1.00 mg·L^-1， representing T₀， T₁， T₂， T₃， T₄ treatment， respectively） were sprayed on the leaves. After 5 days， the morphological and physiological indexes of the seedlings were measured. The results showed that low temperature stress significantly inhibited the growth of alfalfa seedlings. However， after applying different concentrations of BR， the plant height， leaf length， leaf width， leaf area， aboveground and underground biomass， root shoot ratio， total root length， total root surface area， root diameter， root volume， root tip number， root activity， phenylalanine ammonia lyase， cinnamic acid-4-hydroxylase， 4-coumaric acid coenzyme A ligase and total flavonoid content of alfalfa seedlings were significantly higher than those of T₀ （P<0.05）. The content of malondialdehyde decreased significantly （P<0.05）. The comprehensive evaluation of membership function showed that different concentrations of BR treatments were in the order of T₂>T₁>T₃>T₄>T₀， indicating that spraying 0.25-1.00 mg·L^-1 BR could alleviate the effects of low temperature on the growth of alfalfa seedlings， while the 0.5 mg·L^-1 （T₂） BR treatment was the best. The results provided a theoretical basis for the rational use of BR to solve the problem of chilling injury in alfalfa cultivation.

To investigate the effects of biochar and manure on the growth and nutritional quality of silage maize （Zea mays）， the experiment was conducted to determine the agronomic traits of silage maize at different growth stages， yield and nutritional quality by setting up 8 fertilization treatments of single or combined application of biochar， manure and inorganic fertilizer with no fertilization （CK） as the control. The results showed that biochar and manure could promote the growth of silage maize and improved its nutritional quality， and the combined application of biochar and manure was more effective than single application. Compared with no fertilization （CK）， single application of biochar （B） increased the fresh and hay forage yield of silage maize by 33.5% and 29.7%（P<0.05）， respectively. Under the condition of no chemical fertilizer， the content of ether extract， relative feeding value， total potassium and zinc in biochar combined with manure （BM） treatment was the highest， and the total phosphorus content of plants was significantly increased， while the neutral detergent fiber was reduced by 20.5% （P<0.05）. Under the condition of applying inorganic fertilizer， compared with the treatment of applying inorganic fertilizer （F） alone， the fresh forage yield， hay forage yield and zinc content of biochar combined with manure （BMF） treatment were the highest， and the acid detergent fiber decreased by 9.6% （P<0.05）. In summary， biochar combined with manure can significantly improve the production performance of silage maize， and provides theoretical guidance for promoting forage yield increase and farmland improvement in arid and semiarid areas.

To address the current status of soil phosphorus deficiency， this study aimed to develop novel， safe， and efficient microbial fertilizers. Polygonatum cirrhifolium from Tibet was used as the test material， and the streak plate method was employed to isolate and screen phosphorus-solubilizing strains. Their phosphorus-solubilizing capacity was determined， and the culture conditions were investigated. The results showed that a total of 9 phosphorus-solubilizing bacterial strains were isolated. Among them， 5 strains with a phosphate solubilization index （PSI）>2.0 were screened， with phosphorus-solubilizing capacities ranging from 29.603 to 41.730 mg·L^-1. The strains were identified as follows： JYHJ-1 as Pseud-omonas yamanorum， JYHJ-2 as Pseudomonas koreensis， JYHJ-3 as Serratia proteamaculans， JYHJ-4 as Pseudomonas azotoformans， and JYHJ-5 as Microbacterium oxydans. Strain JYHJ-3 exhibited the strongest phosphorus-solubilizing ability， and it could secrete 7 types of organic acids as well as possess capabilities such as siderophore production， potassium solubilization， nitrogen fixation， and indole-3-acetic acid （IAA） production. In the single-factor experiments， the optimal phosphorus-solubilizing efficiency was achieved when lactose was used as the carbon source， ammonium acetate as the nitrogen source， initial pH was 5.5， inoculation volume was 2%， and NaCl concentration was 1%. Based on the single-factor experiments， response surface methodology （RSM） was applied to optimize the initial pH， inoculation volume， and NaCl concentration. The final optimal culture conditions were determined as follows： lactose as the carbon source， ammonium acetate as the nitrogen source， initial pH 5.5， inoculation volume 3%， and NaCl concentration 1%. In conclusion， the rhizosphere of Polygonatum cirrhifolium was rich in phosphorus-solubilizing bacterial resources. This study provided strain resources and a theoretical basis for the sustainable cultivation of medicinal Polygonatum cirrhifolium and the development of microbial fertilizers.

To screen the optimal Arbuscular mycorrhizal fungus （AMF） for Berberis poiretii Schneid. and B. sibirica Pall. and thereby accelerate commercial propagation of the genus， seedlings of both species were inoculated with Funneliformis mosseae （Fm）， Claroideoglomus etunicatum （Ce）， a 1∶1 mixture of both （Mix）， or left non-inoculated （CK）. Mycorrhizal colonization， growth and physiological parameters， and berberine concentration were subsequently quantified. Colonization peaked under Mix in B. poiretii and under Ce in B. sibirica. Root architecture responded similarly： Ce produced the greatest root-tip number and total root length in both species （significantly so in B. sibirica）， whereas Mix maximized mean root diameter and root volume， root surface area did not differ among treatments. Soluble-protein content and superoxide dismutase （SOD） activity were highest after Ce inoculation and the lowest in CK for both taxa. Peroxidase （POD） activity was also the highest under Ce in B. poiretii， but under Fm in B. sibirica. In conclusion， AMF inoculation consistently stimulated growth， antioxidant capacity， and berberine biosynthesis in the two Berberis species， providing a practical pratical referances for their large-scale cultivation.

Drought stress inhibits seed germination of alfalfa （Medicago sativa L.） and reduces its yield. This research studied the effects of cerium oxide nanoparticle priming on seed germination and physiological characteristics of alfalfa under drought stress. Alfalfa seeds were used as materials and primed with different concentrations of cerium oxide nanoparticle （CeO₂NPs） solutions （0， 50， 100， 150， 200 mg·L^-1） in the dark for 24 hours. Drought stress was simulated with 15% PEG to explore the mitigating effect of CeO₂NPs on seed germination. The results showed that 15% PEG significantly inhibited seed germination， while priming with 150 mg·L^-1 CeO₂NPs increased the germination rate to 77% （P<0.05）， which was 5% higher than the non-primed treatment. It also shortened the average germination time， increased the germination index， and enhanced the fresh weight of germinated seedlings. At the physiological level， the 150 mg·L^-1 CeO₂NPs priming treatment increased the activities of α-amylase and β-amylase， and significantly reduced the contents of reducing sugar （P<0.05）； the 100 mg·L^-1 treatment significantly improved the activity of antioxidant enzymes； the 50 mg·L^-1 treatment effectively reduced the ROS content； all concentrations of CeO₂NPs priming treatments significantly decreased the malondialdehyde content （P<0.05） and the proline content， and increased the soluble protein content as osmotic adjustment substances. Comprehensive analysis indicated that 150 mg·L^-1 CeO₂NPs priming had the best mitigating effect on alfalfa seed germination under drought stress.

To investigate the regulatory effects of exogenous ammonium sulfate on the silage quality and hydrogen cyanide （HCN） degradation of regrowth waxy sorghum [Sorghum bicolor （L.） Moench]， a 60-day silage experiment was conducted with three addition levels of ammonium sulfate （0%， 0.3%， and 0.5% of dry matter）. Fermentation characteristics， nutritional composition， feeding value， and HCN dynamics were continuously monitored. Principal component analysis （PCA） and redundancy analysis （RDA） were employed for comprehensive evaluation. The results showed that ammonium sulfate significantly improved both nutritional quality and silage safety. The 0.5% ammonium sulfate treatment increased crude protein by 12.3%， while neutral detergent fiber （NDF） and acid detergent fiber （ADF） decreased to 43.82% and 27.60%， respectively. Lactic and acetic acid concentrations increased by 35.7% and 28.4%， accelerating acidification （pH<4.2 within 7 days） and suppressing undesirable microorganisms. HCN degradation rate increased by 40% between 7 and 15 days， with final residual content below 170 mg·kg^-1 and a degradation rate of 53% after 60 days. Feeding performance was also enhanced， with relative feed value （RFV） and relative forage quality （RFQ） reaching 160 and 180， respectively. Overall， ammonium sulfate at 0.4%-0.6% of dry matter effectively improved silage fermentation， nutritional quality， and safety， meeting the standards for high-quality forage （RFV>145， HCN<200 mg·kg^-1） and providing a scientific basis for developing the “grain-forage dual-purpose” sorghum production model.