To reveal the spatial distribution characteristics and driving mechanisms of soil microbial biomass carbon （MBC）， nitrogen （MBN）， and phosphorus （MBP） stoichiometry under precipitation gradients， this study collected 57 sampling points of three grassland types along a 3000 km transect in Inner Mongolia. The spatial distribution characteristics of microbial biomass and its stoichiometry were analyzed， and their relationship with climate and soil physicochemical factors was explored. The results showed that MBC content was significantly higher than that of MBN and MBP. Microbial biomass was positively correlated with available carbon， nitrogen， and phosphorus in the soil. MBN was negatively correlated with aridity， mean annual temperature （MAT）， and soil bulk density （SBD）. MBP was negatively correlated with aridity， MAT， and soil pH. The microbial biomass carbon-nitrogen ratio （Mcn） was significantly negatively correlated with mean annual precipitation （MAP）， the microbial biomass carbon-phosphorus ratio （Mcp） was significantly positively correlated with aridity， and the microbial biomass nitrogen-phosphorus ratio （Mnp） was significantly positively correlated with soil pH. Random forest analysis indicated that MAP， aridity， and soil pH were the main driving factors of microbial biomass. This study deepened our understanding of the response of soil microorganisms to climate change and provided theoretical support for protecting the nutrient cycling function of grassland ecosystems.

The GRAS family is a class of specific transcriptional regulatory factors widely present in plants， which play vital roles in regulating plant growth and development， as well as responses to biotic and abiotic stress. It is of great significance to explore the characteristics and functions of GRAS gene family in elephant grass （Pennisetum purpureum） and clarify their regulatory roles under low-temperature stress. Based on the genomic data of elephant grass， in this study we identified members of the GRAS gene family， and analyzed their chromosomal localization， physicochemical properties， gene structural characteristics， phylogenetic relationships， as well as the expression patterns of elephant grass materials with different cold resistance under low-temperature stress. The results showed that a total of 18 GRAS genes were identified in the elephant grass genome， which were distributed on 10 chromosomes and classified into five subfamilies via phylogenetic analysis. Cis-acting element analysis revealed that the promoter regions of 10 PpGRAS members contained regulatory elements related to low-temperature response. Collinearity analysis indicated that elephant grass shared more homologous genes with Sorghum bicolor than that with Oryza sativa. Expression pattern analysis demonstrated that the expression levels of multiple GRAS family members， especially genes such as PpGRAS7 and PpGRAS10 belonging to the LISCL subfamily， were significantly positively correlated with cold resistance capacity of materials. This study provides valuable references for further exploring the functions of elephant grass GRAS family and their response mechanisms to Low-temperature stress.

To investigate the responses of soil carbon， nitrogen， and phosphorus content and their stoichiometric characteristics in alpine wetlands of the Qinghai-Tibet Plateau to nitrogen and phosphorus addition， this study took the Gahai swamp meadow as the research subject. Through field manipulation experiments， four treatments were established： control （CK）， nitrogen addition （N）， phosphorus addition （P）， and combined nitrogen-phosphorus addition （NP）. The research explored the response patterns of soil nutrient contents and their stoichiometric characteristics in the 0~40 cm soil layer to three consecutive years of nitrogen and phosphorus addition. Results indicated that nitrogen， phosphorus， and combined nitrogen-phosphorus applications reduced soil pH， bulk density， soil water content， and ammonium nitrogen content while increasing aboveground biomass. Nitrogen application alone increased nitrate nitrogen content. All treatments reduced soil organic carbon and C∶N ratios while increasing total nitrogen and N∶P ratios. Individual nitrogen and phosphorus addition significantly increased total phosphorus content and decreased C∶P ratios， whereas the combined addition of nitrogen-phosphorus showed no significant changes in these parameters. Correlation analysis revealed highly significant negative correlations between C∶N and total nitrogen， as well as N∶P； significant positive correlations existed between C∶P and organic carbon， N∶P， and between N∶P and total nitrogen. Soil total nitrogen emerged as the primary driver of changes in soil stoichiometric characteristics. Effect analysis indicated positive effects of different nutrient additions on both total nitrogen and N∶P ratios. In summary， nitrogen and phosphorus additions exerted significant effects on soil carbon， nitrogen， and phosphorus， providing insights for predicting responses of alpine wetland ecosystems to climatic and environmental changes and formulating conservation strategies.

This study aimed to evaluate the effects of replacing whole-plant corn with waste tea branches and leaves on the aerobic stability of fermented total mixed ration （FTMR）. Five treatments were prepared based on dry matter ratios： 0%， 10%， 20%， 30%， and 40% substitution levels （T0， T10， T20， T30， and T40）. The samples were vacuum-packed （35 cm×45 cm， approximately 400 g per bag， four replicates per treatment） and fermented for 60 days. After fermentation， aerobic exposure was conducted for 0， 1， 3， 5， 8， and 14 days to determine temperature， nutrient composition， fermentation quality， and microbial counts. The results showed that crude protein content increased with higher substitution levels， and the decline in crude protein during aerobic exposure was reduced. T10 and T20 exhibited slower temperature rise and maintained a temperature difference below 2 ℃ for a significantly longer duration （P<0.05）， indicating better aerobic stability. T10 maintained lower pH， higher lactic acid content， and higher V-score during aerobic exposure， showing superior fermentation quality. In contrast， T40 had higher crude protein but showed rapid pH increase and early mold growth， indicating poorer quality. In conclusion， moderate inclusion （10%-20%） of waste tea branches and leaves improves both aerobic stability and fermentation quality of FTMR.

Hybrid Pennisetum （Pennisetum glaucum × P. purpureum） is an important high-yield and high-quality forage grass； however， its poor cold tolerance restricts its cultivation and utilization in northern and high-latitude regions. Heavy-ion irradiation is a relatively new mutagenic approach and has been rarely applied in forage breeding. In this study， seeds of the hybrid Pennisetum cultivar ‘Bangde No.1’ were treated with heavy-ion irradiation at doses of 50， 100， 150， 200， and 300 Gy. Seedling growth traits and physiological responses under low-temperature stress were systematically evaluated to investigate the mutagenic effects of heavy-ion irradiation， establish a heavy-ion mutagenesis system for hybrid Pennisetum seeds， and develop novel cold-tolerant germplasm. The results showed that heavy-ion irradiation exerted a clear dose-dependent effect on hybrid Pennisetum. Among the treatments， 100 Gy not only maintained a high seedling establishment rate but also significantly increased soluble sugar content and the activities of superoxide dismutase （SOD） and peroxidase （POD）， reduced membrane damage， and resulted in the lowest semi-lethal temperature （LT₅₀） of plant mutants， indicating the strongest cold tolerance and relatively high mutagenic efficiency. Based on a comprehensive evaluation integrating laboratory and field assessments， principal component analysis， membership function analysis， field survival rate， and field overwintering rate， three potential cold-tolerant mutants were identified from the M₁ generation.

To explore the effects of moisture content and mixing ratio on the silage quality of Avena sativa and Sesbania cannabina mixed silage， this experiment was designed with three moisture content gradients （55%-60%， 60%-65%， 65%-70%） and seven mixing ratios （fresh weight ratio from 100∶0 to 0∶100）. Samples were vacuum ensiled for 60 days， after which nutritional and fermentation quality indices were determined， and a comprehensive evaluation was conducted using the membership function method. The results showed that moisture content， mixing ratio， and their interaction had significant effects on silage quality （P<0.05）. With the increase of moisture content， dry matter （DM）， crude protein （CP） and water-soluble carbohydrates （WSC） decreased， while fiber content， lactic acid （LA） content and relative forage quality （RFQ） increased. pH and butyric acid （BA） decreased first and then increased， and acetic acid （AA） increased first and then decreased. Among the mixing ratios， Avena sativa silage had the highest DM content， Sesbania cannabina silage had the highest CP， WSC， and LA contents， and the 30∶70 mixture （Avena sativa∶Sesbania cannabina） exhibited the optimal RFQ. Higher Sesbania cannabina ratios resulted in lower fiber contents. The pH values of all treatments were below 4.2. Comprehensive evaluation revealed that the mixed silage with 60%-65% moisture content and an Avena sativa-to-Sesbania cannabina ratio of 30：70 performed the best， and Sesbania cannabina silage with 55%-60% moisture content also showed excellent quality. The former can be recommended in production to achieve balanced nutrition， and the latter can be adopted for high nutrient value and single raw material utilization.

To screen cold-tolerant germplasm resources of Pennisetum， clarify the cold resistance differences among different germplasms， and provide a theoretical basis for cold resistance breeding， 118 Pennisetum germplasm resources were used as experimental materials in this study， and comprehensive evaluation of cold resistance was carried out via field low-temperature stress treatment combined with eight cold resistance-related indicators. The results revealed that the cold resistance-related traits of the tested germplasms possessed abundant genetic diversity， which could provide sufficient genetic basis for cold resistance breeding. Chlorophyll content was significantly correlated with regrowth seedling number and stem sugar content， serving as key factors affecting cold resistance differences among Pennisetum germplasms. Principal component analysis simplified eight indicators into four principal components with a cumulative contribution rate of 80.924%， with chlorophyll reduction value after low-temperature stress， chlorophyll content under low temperature， regrowth seedling number and stem sugar content identified as the core indicators. Based on cluster analysis， all the germplasms were classified into three groups， and a total of 30 excellent cold-resistant germplasms including Pp20230630-3， Pp20230628-5 and Pp014 were screened out using membership function method. This study provides important germplasm resources and theoretical references for cold-resistant germplasm innovation and new variety breeding of Pennisetum.

The features of ecological restoration， ornamental garden， and forage values are possessed by pennisetum plants. Research on the genetic diversity of pennisetum germplasm resources can be conducted to offer theoretical basis for new variety breeding， development， and utilization. In this study， 48 Pennisetum germplasm resources were used as materials. Through phenotypic trait determination and SSR molecular marker technology， phenotypic characteristics， genetic diversity， and population structure were systematically evaluated. The results showed that the coefficient of variation for four phenotypic traits was observed to range from 28.10% to 96.92%， with a genetic diversity index of 2.49 to 2.83， indicating rich diversity. Plant height was found to be significantly positively correlated with leaf width， while tillering was observed to be significantly negatively correlated with plant height and significantly negatively correlated with leaf width. Phenotypic clustering was determined to be divisible into three categories. A total of 122 alleles were detected from 20 primer pairs by SSR markers， with an average of 6.10 per pair. Shannon’s diversity index was measured to range from 0.35 to 0.64， polymorphism information content was measured to range from 0.25 to 0.79， and the average genetic distance was calculated to be 0.43. UPGMA clustering was divided into three to five categories as the similarity coefficient was increased， and the population genetic structure was determined to be divisible into three groups with significant differences in genetic background among groups. In this study， the genetic diversity and population structure of 48 Pennisetum germplasm resources were elucidated， and a theoretical foundation was laid for subsequent germplasm identification and new variety breeding.

Appropriate concentrations of ethephon can improve the drought tolerance of turfgrasses， but the specific mechanism of action remains unclear. As an osmotic regulator， proline plays an important role in plant responses to stress. In this study， Kentucky bluegrass （Poa pratensis） and perennial ryegrass （Lolium perenne） were used as materials. We examined the effects of ethephon on physiological indices of turfgrasses in response to drought stress， analyzed changes in the expression of genes related to proline biosynthesis and catabolism， and explored the role of proline in ethephon-improved drought resistance of turfgrasses. The results showed that ethephon alleviated the decrease of relative water content and the increase of electrolyte leakage of turfgrass leaves induced by drought stress， thus contributing to improved drought tolerance. Under drought stress， proline content increased in the two Poa pratensis cultivars， whereas the changes were inconsistent among Lolium perenne cultivars. Ethephon treatment down-regulated the expression of Proline Dehydrogenase （Pro DH） gene in Poa pratensis under drought stress， thereby inhibiting proline degradation. In conclusion， promoting proline accumulation by suppressing the expression of the Pro DH gene might be one of the mechanisms by which ethephon improves drought tolerance in Poa pratensis.

Previous in situ warming experiments have predominantly employed open-top chamber and infrared radiation for aboveground warming， which fail to adequately simulate the warming process in deeper soil （>30 cm）. In contrast， the whole-ecosystem warming， warming both aboveground vegetation and soil profile， represents the most realistic field-scale warming method. Peatland ecosystems are the terrestrial ecosystems with the highest organic carbon density per unit area globally. However， how their carbon sequestration function respond under climate warming remains inconclusive. This study focused on the Zoige alpine peatlands in Hongyuan County， Sichuan Province， China. A field experiment was established with four warming treatments， including control （CK）， above-ground warming （AW）， whole-soil profile warming （BW） and whole-ecosystem warming （EW）. This research analyzed the effects of different warming treatments on ecosystem carbon fluxes in the peatland ecosystem and the regulatory mechanisms. The results showed that elevating soil temperature and decreasing soil profile moisture content were key regulators of ecosystem carbon fluxes. BW and EW all promoted ecosystem respiration （ER）， while AW had no significant effect on ER. EW significantly reduced both soil profile water content and promoted soil evaporation， leading to a notable decrease in net ecosystem productivity （NEP）. Although EW stimulated plant growth and increased carbon inputs， the enhanced respiration effect outweighed the warming-induced stimulation of photosynthesis， resulting in a significant weakened carbon sink. This study provides a scientific basis for accurately assessing the carbon sequestration function of alpine peatlands under climate warming.