Carex breviculamis is an important native species that is water-saving and drought resistant， with advantages such as long green period， shade tolerance， and high fruiting rate. However， in the actual harvesting process， the problem of seeds easily falling off limits the mechanization of seed harvesting and large-scale production applications. In order to explore the function of SH4 gene in the process of seed-shattering in C. breviculmis and further use gene editing technology to create new germplasm resistant to seed shattering， the CbSH4 gene was cloned and the gene editing target was screened. The CbSH4 encoded 319 amino acid residues， was a hydrophilic protein， and was most closely related to Carex littledalei， containing a highly conserved Myb4 DNA-binding domain， which belonged to a typical MYB transcription factor. The transient expression results of Nicotiana benthamiana showed that CbSH4 protein was localized in the nucleus and cytoplasm. The real-time fluorescence quantification results showed that the relative expression level of CbSH4 in the spike was significantly higher than that in the roots and leaves， and it was expressed in the abscission zone at different developmental stages. At the same time， in order to achieve efficient gene editing in C. breviculmis， three specific targets were designed in this study， and sgRNA1 was obtained by sgRNA transcription and screening in vitro with a cleavage efficiency of 58.3%， which could be used for subsequent gene editing of C. breviculmis. In this study， CbSH4 was successfully cloned and the preliminary functional analysis was completed， and the high-efficiency gene editing targets were screened， which provided a basis for the creation of new germplasm with low seed shattering.

In order to study the adaptability of Sorghum sudanense to salt stress， 10 varieties of Sorghum sudanense with different salt tolerance grades were used as materials and treated with different concentrations of NaCl solution at the germination stage to study the morphological indexes physiological characteristics， and leaf anatomical structure changes. The results showed that salt stress had a significant effect on the morphological indexes of S. sudanense， especially under high salt concentration. In addition， salt stress could significantly increase the contents of malondialdehyde， proline and soluble protein in S. sudanense leaves. With the increase of salt concentration， the activities of peroxidase and superoxide dismutase in salt-tolerant materials continued to increase， while the activities of the two enzymes in salt-sensitive materials increased first and then decreased. Salt stress significantly increased the thickness of midvein， thickness of vascular bundle， thickness of bulliform cells and thickness of lower epidermal cell of high-sensitivity S. sudanense leaves， and significantly decreased the thickness of midvein， thickness of leaf and thickness of vascular bundle of high-sensitivity S. sudanense leaves. Principal component analysis （PCA） was used to screen proline， thickness of vascular bundle， thickness of leaf and thickness of upper epidermal cell as the key indexes for salt tolerance screening of S. sudanense.

To investigate the mechanisms of the effects of different frequencies and intensities of freeze-thaw cycles on the soil carbon mineralization process and the characteristics of stable carbon isotope （δ¹³C） fractionation in alpine swamp meadows， this study focused on the soil of alpine swamp meadows on the Qinghai-Tibet Plateau. Two freeze-thaw intensities （-15 to 15℃ and -10 to 10℃， a total of 15 freeze-thaw cycles） and a control group at 10℃ were established. A 15-day indoor continuous monitoring experiment was conducted to compare the dynamics of carbon mineralization and changes in δ¹³C. The results showed that low-intensity freeze-thaw cycles significantly inhibited the rate of carbon mineralization， causing a decrease of 7.67%. In contrast， high-intensity freeze-thaw cycles significantly promote the cumulative carbon mineralization， with an increase of 2.70%. The differences among treatments were relatively small after the first 3 freeze-thaw cycles， but the growth rate of carbon mineralization significantly slowed down under the low-intensity treatment after the third cycle. The δ¹³C values under different freeze-thaw intensities ranged from -21.49‰ to -28.03‰， which showed -15-15℃>10℃>-10-10℃， and showed a trend of first decreasing and then increasing with the increase of freeze-thaw frequency. Redundancy analysis （RDA） showed that ammonium nitrogen （NH₄⁺-N） and microbial biomass nitrogen （MBN） were the key factors regulating carbon mineralization and isotope fractionation. Under the -15-15℃ treatment， δ¹³C values were significantly positively correlated with nitrate nitrogen （NO₃^--N）. In contrast， under the -10-10℃ treatment， the carbon mineralization rate was significantly negatively correlated with MBN and significantly positively correlated with microbial biomass carbon to microbial biomass nitrogen ratio （MBC/MBN）. Additionally， its stable isotopes were significantly positively correlated with NH₄⁺-N and MBC/MBN. Overall， the reduced freeze-thaw intensity significantly inhibits soil carbon mineralization processes and causes changes in microbial metabolic pathways. It is crucial to pay attention to the long-term impacts of the continued weakening in freeze-thaw intensity on the carbon sequestration function of alpine wetlands.

The soil carbon cycle constitutes the core of the global carbon cycle， governing the carbon sink function of terrestrial ecosystems. As key driving factors， nitrogen and phosphorus additions regulate the balance between soil carbon sequestration and release by altering the transformation processes of soil carbon fractions and microbial community activities. Based on CiteSpace bibliometric analysis， this study systematically reviewed global research progress over the past decades. Results indicated that the number of studies were growing exponentially， with research hotspots focusing on： the dynamics of labile and stable carbon fractions in soils， metabolic responses of microbial functional communities， and the nonlinear equilibrium of carbon input-output fluxes. While domestic research had made significant contributions to regional differential response mechanisms and micro-scale analysis of microbial-carbon coupling processes， shortcomings persisted in experimental designs for multi-factor interactions and the integration of long-term observational data. Future research should prioritize breakthroughs in long-term in-situ controlled experiments to elucidate the coupling mechanisms between nitrogen-phosphorus stoichiometry and carbon component transformation， and achieve precision prediction of carbon turnover through model-data fusion. This study provides a theoretical framework for quantitatively evaluating the carbon sequestration potential of grassland ecosystems under anthropogenic nitrogen and phosphorus input， and has guiding significance for the adaptive management of ecosystems under the goal of “Double Carbon”.

This study aims to screen the suitable grass species with low sowing rate and high coverage. Four ecological grass species， Poa pretensis ‘Qinghai’， Deschampsia cespitosa， Koeleria macrantha and Elymus tangutorum， were selected as experimental materials to carry out the screening experiment of suitable sowing rate. The characteristics of plant phenotypic traits， biomass and soil nutrients under three sowing rates were analyzed. The results showed that when the sowing rate was 9 g·m^-2， the aboveground biomass of Poa pretensis ‘Qinghai’， Deschampsia cespitosa and Koeleria macrantha were the highest， which were 296.45 g·m^-2，224.32 g·m^-2 and 236.35 g·m^-2 respectively. The aboveground biomass of Elymus tangutorum was 356.24 g·m^-2 when the seeding rate was 18 g·m^-2， which was significantly higher than other treatments （P<0.05）. When the sowing amount of Poa pretensis ‘Qinghai’， Deschampsia cespitosa and Koeleria macrantha reached 9 g·m^-2， the soil nutrient indexes such as organic matter， total nitrogen and total phosphorus performed well. The seeding rate of Elymus tangutorum was 18 g·m^-2， which showed a good soil nutrient status. Principal component analysis of 13 indexes of plants and soil showed that the cumulative contribution rate of the first five principal components reached 89.615%. The comprehensive evaluation of membership function showed that the comprehensive evaluation values of Poa pretensis‘Qinghai’， Deschampsia cespitosa and Koeleria macrantha were the highest when the sowing amount was 9 g·m^-2， which were 0.420， 0.486 and 0.698 respectively. When the seeding rate of Elymus tangutorum was 18 g·m^-2， the comprehensive evaluation value was the highest， which was 0.634. To sum up， 9 g·m^-2 is the most suitabel sowing amount for planting Poa pretensis‘Qinghai’， Deschampsia cespitosa and Koeleria macrantha in Muli mining area， and 18 g·m^-2 is Elymus tangutorum in Muli mining area.

To investigate the effects of different additives on the silage quality and microbial population of Elymus dahuricus，Elymus dahuricus was used as the raw material and herein and set up five treatment groups： P₁ （no additive， add the same amount of distilled water）， P₂ （adding Lactobacillus plantarum，the addition amount was 1×10⁶ CFU·g^-1 FW）， P₃ （adding molasses， the addition amount was 20 g·kg^-1 FW）， P₄ （adding Lactobacillus buchneri，the addition amount was 1×10⁶ CFU·g^-1 FW）， and P₅ （adding cellulase，the addition amount was 50 U·g^-1 FW）. After 60 days of ensiling， the nutritional quality， fermentation characteristics， and microbial counts were determined. The results showed that different silage additives significantly affected the contents of water soluble carbohydrates （WSC）， neutral detergent fiber （NDF）， acid detergent fiber （ADF）， and crude ash in Elymus dahuricus silage（P<0.05）. The additives significantly decreased the pH value of the silage and significantly increased the lactic acid content （P<0.05）， while significantly reducing the propionic acid content （P<0.05）. Comprehensive membership function analysis indicated that quality of Elymus dahuricus silage was the best when the addition amount was 20g·kg^-1 FW molasses.

Grassland degradation is one of the major global ecological challenges， especially in the arid and semi-arid areas of northwest China， where degraded grassland seriously affects the ecosystem functions and the development of animal husbandry. In this study， a four-year field experiment was conducted in Yuyang District， Shaanxi Province， and systematically evaluated the effects of reseeding and modern intensive grazing techniques on degraded grassland productivity， vegetation community structure， soil physicochemical properties， and meat quality of sheep. The results showed that reseeding significantly enhanced grassland productivity， particularly by increasing the biomass proportion of legumes， which increased soil nitrogen content and improved vegetation nutritional quality. In addition， principal component analysis （PCA） revealed that reseeding restructured plant communities to include more plants with high nutrtional value. Grazing on reseeded grassland increased amino acid content in sheep meat and enhanced its flavor. In general， reseeding technology plays a pivotal role in restoring degraded grassland and advancing sustainable development of animal husbandry， offering a scientific foundation for grassland management in arid and semi-arid areas.

In　this study， 15 oat varieties were used to investigated the effects of different seed moisture content [12% （T1）， 14% （T2）， and 16% （T3）] and storage methods （conventional and hermetic storage） on the germination characteristics. The results revealed that there were significant genotypic differences （P<0.05） in response to moisture stress among the varieties， which were further influenced by storage duration and method. For example， ‘Baiyan 7’ exhibited the best performance during the initial germination stage at 16% moisture treatment （T3）， whereas varieties such as ‘Qinghai Sweet Oat’ showed higher germination rates under low moisture conditions （T1）. In addition， storage methods significantly altered moisture sensitivity of varieties： conventional storage increased the suitable moisture threshold to T3 for certain varieties， while hermetic storage reduced the moisture requirement of most varieties. Embryo development analysis revealed that distinct patterns in radicle and plumule biomass responses to moisture levels among varieties. Hermetic storage induced a shift from linear to peak-curve responses in these traits. Differential sensitivity to moisture between radicles and plumules was also observed， indicating genotype-specific resource allocation strategies. Hermetic storage had a highly significant effect （P<0.01） on oat seed germination characteristics. Based on TOPSIS comprehensive evaluation， ‘Qingyan 1’ was identified as the best stablity. Furthermore， strong correlations were observed between embryo indicators and germination parameters， suggesting that they could be used as a reliable predictor of seed vigor.

Soil nematodes are pivotal for material cycling and energy flow in grassland ecosystems. Clipping is a widespread grassland management practice in northern China. However， the mechanisms by which clipping affects the composition and structure of soil nematode communities remain unclear. nematode functional footprints across plant communities remain poorly understood. This experiment examined how clipping influenced soil nematode composition， structure， and functional footprint across six plant communities in the typical steppe of Inner Mongolia， providing a theoretical basis for grassland ecosystem management. Clipping significantly increased the total abundance of soil nematodes， the relative abundance of bacterivores， the maturity index， and the Wasilewska index. At the same time， it reduced the relative abundance of plant parasitic nematodes， the nutritional diversity index， the Shannon-Wiener index， the evenness index， and the enrichment index. Fauna analysis revealed that clipping increased the functional footprint of soil nematodes and food web complexity， while it reduced the enrichment index. Soil nematode community composition was significantly affected by soil nitrate nitrogen content， total carbon content， and litter mass. Our results demonstrated that clipping restructured nematode community composition， reducing plant parasitic nematodes’ abundance， thereby improving soil nutrient functions and promoting plant growth. This study concludes that clipping effectively maintains soil nematode community structure in typical steppe， offering a science-based framework for sustainable grassland management in northern China.

This experiment was conducted to study the effects of combined application of organic fertilizer and chemical fertilizer on the production performance， nutritional quality and economic benefits of different triticale （×Triticosecale） varieties， and to provide theoretical basis for high yield cultivation techniques of triticale in dry farming areas of central Gansu. The experiment used a split-plot design， and the main plot factor was nitrogen application rate， which was set at four levels： 120 （A1）， 240 （A2）， 360 （A3）， and 480 kg·hm^-2 N （A4）. For these nitrogen application treatments， nitrogen was applied as a combination of organic fertilizer and urea， with 2/3 of the nitrogen from organic fertilizer used as base fertilizer and 1/3 from urea as topdressing. Two control treatments were also included： no fertilization （CK1） and single application of chemical fertilizer （CK2）. The subplot was two triticale varieties （C1： ‘Gannong No.2’； C2： ‘Gannong No.4’）. The results showed that among the fertilization treatments， when the combined application rate of organic fertilizer and chemical fertilizer was 360 kg·hm^-2 N， the average hay yield （8.36 t·hm^-2）， crude protein content （10.73%）， and comprehensive evaluation value （0.95%） of the two triticale varieties were relatively higher. From the perspective of triticale varieties， the comprehensive evaluation value of ‘Gannong 2’ triticale （0.60） was higher than that of ‘Gannong 4’ triticale （0.40）. Their interaction showed that when the combined application of organic fertilizer and chemical fertilizer was 360 kg·hm^-2 N， the comprehensive evaluation value of Gannong No.2 was the highest （0.84）， which was higher than that of the two triticale varieties under single application of chemical fertilizer （0.52， 0.72）. In conclusion， under dry climate conditions， to balance high-quality and high-yield forage as well as economic benefits， the recommended nitrogen application strategy is as follows： for ‘Gannong 2’ triticale， a combined application of organic fertilizer and chemical fertilizer at a rate of 240 kg·hm^-2 N is suitable； for 'Gannong 4' triticale， a single application of chemical fertilizer at 360 kg·hm^-2 N is appropriate.