This study employed conventional chromosome squash techniques to analyze the ploidy levels and karyotypes of eight samples from five Gynostemma species， aiming to investigate their evolutionary trends and phylogenetic relationships. The results revealed that all eight samples exhibited a basic chromosome number of 11. Among them， G.pentaphyllum collected from Fujian Nanjing was tetraploid， while the remaining seven samples were diploid. Satellite chromosomes were observed in two samples. Chromosome types included two categories： m （metacentric） and sm （submetacentric）. Karyotype classifications comprised four types： 1A， 2A， 1B， and 2B. The ratio of the longest to shortest chromosome ranged from 1.48 to 3.26， with an average arm ratio of 1.26-1.45. The karyotypic asymmetry coefficient varied between 55.59% and 58.56%. Based on karyotype evolution， the samples were ordered as follows： GXH， WZ>GXY>AH， FJ>MD， GXB， YJ. These findings provide cytological evidence for the taxonomic classification and phylogenetic analysis of Gynostemma species.

To clarify the effects of different grazing intensities on the plant community structure， species diversity， and population niche characteristics in desert steppe， reveal the laws of community species replacement and the niche response mechanisms of dominant species， and provide a theoretical basis for scientific grazing management， this study set up four different grazing treatments to analyze changes in community species composition， diversity， and niche characteristics. The results showed that with the increase of grazing intensity， the community species shifted from perennial forbs and shrubs/subshrubs to perennial grasses； grazing significantly reduced the total aboveground biomass of the community and the biomass of various functional groups， and the Shannon-Wiener index， Simpson index， and species richness index. Stipa breviflora， Cleistogenes songorica， and Convolvulus ammannii maintained a wide niche breadth under all grazing treatments， and the niche overlap among species with high niche breadth was generally high， with the niche overlap between Stipa breviflora and Cleistogenes songorica reaching the highest under the heavy grazing treatment. The study indicated that grazing significantly affected the structure of desert steppe communities by altering the resource competition relationships among species. Therefore， grazing intensity should be controlled in desert steppe management to maintain ecosystem stability.

The development and utilization of saline-alkali land is a key focus for grassland improvement in China， and enhancing the germination capacity of native grass seeds is a crucial step of this process. In this study seeds of Mongolian wheatgrass （Agropyron mongolicum） was used as the material to investigate the effects of nano-iron particle suspensions at different concentrations （25， 50， 75 and 100 mg·L^-1） and different priming duration （4 h and 36 h） on seeds germination， seedling growth characteristics and antioxidant enzyme activities of seedling under 175 mmol·L^-1 mixed salt solution stress （NaCl∶Na₂SO₄=5∶1）. Multispectral imaging technology was also used to rapidly and visually assess seedling vigor and to screen for the most salt-tolerant priming treatments. The results showed that the priming treatment with 4 h significantly outperformed than the 36 h treatment according to the analysis of seed germination and seedling growth indexes （P<0.05）. Nano-iron priming for 4 h at all concentrations significantly improved the germination percentage and germination index （P<0.05）， reduced mean germination time， and increased seedling height， fresh weight， vigor index， and antioxidant enzyme activities （e.g. POD， CAT， APX and MDHAR） in the seedlings （P<0.05）. The nCDA images from multispectral imaging were highly consistent with the trends of these physiological and biochemical changes. Among all the treatments， 50 mg·L^-1 nano-iron priming for 4 h was the most effective， significantly enhancing germinability and growth performance of Mongolian wheatgrass under salt stress and markedly improving its salt tolerance. These findings provide important scientific evidence for vegetation restoration and ecological rehabilitation in saline-alkali lands.

Soil microorganisms serve as key drivers of biogeochemical cycling processes and are essential for maintaining the structure and stability of terrestrial ecosystems. Although existing studies have made progress in understanding the patterns and mechanisms of microbial responses to warming， there remains insufficient integration of microbial response mechanisms and the scientific application of their trait parameters in ecosystem models. Therefore， this paper focused on five core microbial traits： microbial community structure， biomass， extracellular enzyme activity， respiration， and carbon use efficiency. We systematically expounded the response mechanisms of these core traits driven by warming， clarifying the regulatory effects of relevant environmental variables on them. Meanwhile， this paper outlined current research progress in integrating microbial traits into the carbon cycle models， aiming to enhance the accuracy of assessing changes in ecosystem functioning under climate warming. Based on current research progress， we advocated that future studies should focus on long-term field monitoring and multi-ecosystem， large-scale comprehensive investigation. This would enable accurate prediction of the effects of warming on microbial communities， thereby enhancing model prediction capabilities for microbial-driven ecosystem functions. This will advance mechanistic understanding of soil microbial responses to climate warming and provide theoretical support for sustainable ecosystem management.

To explore the role of MfWRKY3 in regulating the response of Medicago falcata to stresses， the MfWRKY3 gene was cloned from wild Medicago falcata in this study， and the characteristics of it encoded protein and the expression pattern were preliminarily identified. The results showed that the length of MfWRKY3 ORF （open reading frame） is 1575 bp， encoding a protein with 524 amino acids， predicted molecular mass of 57.36 kDa and an isoelectric point of 6.96. The MfWRKY3 had transcriptional activation activity and was localized in the nucleus， belonging to the WRKY Ⅰ sub-group transcription factor member. Meanwhile， it was found that the MfWRKY3 gene had the highest expression level in the leaves of Medicago falcate， and the its expression in the roots， stems and leaves were regulated by salt， low temperature and ABA treatment. However， the salt stress could significantly induce the expression of MfWRKY3 gene. These findings laid a foundation for further investigating the biological function and molecular mechanism of MfWRKY3 in regulating the response of Medicago falcata to abiotic stresses.

Elytrigia elongata （Host） Nevski， a perennial bunchgrass， possesses outstanding stress tolerance and forage quality. This study aimed to examine the chromosome number， karyotype composition， and gene expression profiles across various ploidy levels within E. elongata germplasm. Three accessions， designated EE030， EE031， and Ae4x， were used as experimental materials. Karyotype analysis was conducted via an enzymatic maceration method， and differences in gene expression among accessions with varying ploidy levels were analyzed through full-length transcriptome sequencing on the PacBio platform. The results revealed that accession EE031 is a diploid （2n=2x=14） with a karyotype formula of K（2n）=2x=10m+4sm， classified as the “1A” type. Accession Ae4x is identified as a tetraploid （2n=4x=28） with a karyotype formula of K（2n）=4x=20m+6sm+2st， classified as the “2A” type. Accession EE030 is a decaploid （2n=10x=70） with a karyotype formula of K（2n）=10x=56m+12sm+2st， also categorized as the “2A” type. In parallel， transcriptome analysis revealed that increased ploidy level was associated with an essential expansion in transcript abundance and functional diversity. Differentially expressed genes in EE031， Ae4x， and EE030 were enriched in 10， 12， and 15 KEGG metabolic pathways， as well as in 39， 38， and 64 GO functional terms， respectively. Furthermore， core functional pathways specific to each ploidy level were identified： （1） EE031 （diploid） was enriched in proteins related to Chromosomes and Chromosome-binding， Stress response， and Signal receptor activity； （2） Ae4x （tetraploid） was enriched in Transporter and Hydrolase activities； （3） EE030 （decaploid） was associated with Metabolism， Transporter， and Transferase activities.

In this study， Poa pratensis var. Qinghai was used as the research subject. The changing trends in leaf stoichiometric ratios and nutrient resorption efficiency under six phosphorus （P） addition levels （30， 45， 60， 75， 90， and 105 kg·hm^-2， sequentially labeled as P₁， P₂， P₃， P₄， P₅， and P₆） were investigated. The results indicated： （1） The leaf carbon （C）， nitrogen （N）， and P contents generally exhibited the pattern of senescent stage < full ripeness stage < milky ripeness stage， with the highest accumulation of leaf nutrient contents observed under the P₃ level. （2） Leaf C/N and C/P ratios generally followed the pattern of senescent stage > full ripeness stage > milky ripeness stage， while the N/P ratio generally showed full ripeness stage > milky ripeness stage > senescent stage. （3） The Nitrogen Reabsorption Efficiency （NRE） was the highest under the CK （control， no P addition） treatment， whereas the Phosphorus Reabsorption Efficiency （PRE） was the highest under the P₂ addition level. （4） A generally positive correlation was observed between leaf NRE and stoichiometric ratios， while PRE exhibited a generally negative correlation with stoichiometric ratios in mature leaves and a generally positive correlation with stoichiometric ratios in litter leaves. This study suggests that the appropriate P addition amount is P₂-P₃ （45~60 kg·hm^-2）. This research provides practical guidance for precision fertilization and scientific management of artificial grasslands in alpine regions.

To investigate the effects of shrub introduction on soil moisture， C-N-P stoichiometry， and their trade-off relationships in a desert steppe， this study was conducted in the desert steppe of eastern Ningxia. The research compared sites with shrubs introduced for different durations （8， 17 and 27 years） with a site enclosed for grassland restoration for 17 years. Soil water， soil organic carbon （SOC）， total nitrogen （TN）， total phosphorus （TP） contents， and their stoichiometric ratios in the 0-100 cm soil layer were analyzed. The root mean square deviation （RMSD） was used to quantify the trade-off between soil water and nutrients. The results showed that soil water content significantly decreased with increasing shrub introduction years （P<0.05）. Soil TN showed a significant increasing trend （P<0.05）， while TP initially increased and then decreased； both were consistently higher than those in the enclosed grassland. SOC and TN exhibited a strong coupling relationship. The soil N∶P and C∶P ratios fluctuated and decreased with increasing soil depth. Trade-off analysis revealed that the mean RMSD was 0.55 in the enclosed grassland， compared to 0.39 in the sites of shrub introduction. As soil water decreased， the synergistic effect between soil water and nutrients disappeared in the 0-100 cm layer. In summary， nearly 30 years of shrub introduction improved the nutrient content in the 0~100 cm soil layer while maintaining relatively stable soil stoichiometric ratios. However， water stress might emerge as a consequence.

In alpine meadows， the surface soil heaves to form hummocks under the influence of frost heaving， transforming the originally relatively homogeneous habitat into a heterogeneous one. In this study， 9 sampling plots were established along a soil moisture gradient in the alpine meadows of the Western Sichuan Plateau. We compared and analyzed the differences in plant communities and species diversity between hummocks and inter-hummock meadows under different soil moisture conditions. The results showed that： Soil physical properties and soil chemical properties exerted effects on the plant diversity of hummocks and inter-hummock meadows， respectively. The plant community on hummocks gradually transitioned from Kobresia （sedge）-dominated vegetation to shrub-dominated vegetation， while the plant community in inter-hummock meadows gradually shifted from Carex （sedge） and Kobresia-dominated vegetation to grass-dominated vegetation. The abundance of weedy plants and occasional species in hummocks was significantly higher than that in inter-hummock meadows. Habitat aridification increased the dissimilarity in species composition between hummocks and inter-hummock meadows， and the dissimilarity in species composition of hummocks was higher under different soil moisture conditions. In conclusion， hummocks tend to aridify the microhabitat and provide favorable conditions for the invasion of occasional species. Although hummocks increase plant diversity， they have a negative impact on the stability of alpine meadow vegetation. This research holds significant implications for guiding the conservation and management of alpine meadow vegetation.

To investigate the effects of Carboxymethyl cellulose （CMC） on the physiological characteristics of Cynodon dactylon under Salt Stress in vegetation concrete， a controlled simulation experiment was conducted. The experiment utilized Cynodon dactylon as the test material， with four salinity gradients [normal salt level （0 g·kg^-1）， mild Salt Stress （3 g·kg^-1）， moderate Salt Stress （6 g·kg^-1）， and severe Salt Stress （9 g·kg^-1）] and four CMC concentration treatments （0%， 0.1%， 0.2%， 0.4%），The study examined the impacts of CMC on the physiological characteristics of Cynodon dactylon under varying Salt Stress intensities. The results showed that with the intensification of Salt Stress and the extension of stress duration， the physiological performance of Cynodon dactylon decreased. Carboxymethyl cellulose （CMC） treatment effectively enhanced the plant height， biomass， net photosynthetic rate， transpiration rate， stomatal conductance， and proline content of Cynodon dactylon， reduced the intercellular CO₂ concentration and malondialdehyde content ，and enhanced its ability of salt stress. Specifically， under normal salt conditions， mild salt stress， and moderate salt stress， the application of 0.4% CMC yielded the best promoting effect on the growth of Cynodon dactylon； whereas under severe Salt Stress， 0.2% CMC showed the optimal growth-promoting efficacy.