Arbuscular mycorrhizal fungi （AMF） are key symbiotic microorganisms that support nutrient acquisition by grassland plants and contribute to soil structure maintenance. This review synthesizes current progress on how different forms of carbon input， nitrogen addition， and their interactions influence AMF in grassland ecosystems， focusing on colonization， hyphal growth， community composition， and symbiotic network structure. Elevated atmospheric CO₂ mainly promotes AMF hyphal growth and biomass accumulation by increasing belowground carbon allocation in plants. Biochar application and organic fertilizer addition improve soil physical properties and nutrient retention， thereby facilitating AMF colonization and community recovery. In contrast， the effects of soluble organic carbon inputs are moderated by plant functional group identity and nitrogen-phosphorus availability. Long‑term or high‑intensity nitrogen addition generally suppresses AMF， a response closely associated with soil acidification， reduced carbon allocation to mycorrhizae， and reorganization of AMF communities. The interactive effects of carbon inputs and nitrogen addition are constrained by carbon source characteristics， nitrogen legacy effects， and the availability of soil nutrients. Future research should increase the comparability of carbon input studies， clarify the combined regulatory roles of carbon source， nitrogen addition intensity and duration on AMF responses， and provide theoretical support for soil nutrient management and degraded grassland restoration.

Grasses in Pennisetum genus are important high-quality forages in tropical and subtropical regions， characterized by high biomass， strong stress tolerance， and excellent feeding value. They serve as a key resource to alleviate the shortage of forage supply in China. To date， 17 Pennisetum cultivars have been registered in China， most of which are adapted to the southern ecological zones， while there is a lack of stress-tolerant and high-yielding cultivars in northern China， highlighting an urgent need for breeding elite new varieties. This paper reviewed the research progress in conventional breeding techniques， including introduction and domestication， cross breeding， and mutation breeding， as well as molecular breeding approaches such as molecular marker-assisted breeding and genetic engineering. It also analyzed the existing problems， including the shortage of self-incompatible lines， low efficiency of distant hybridization， and an underdeveloped molecular breeding system. Finally， the paper discussed prospects for germplasm resource exploration， optimization of breeding objectives， and application of new technologies， aiming to provide a reference for genetic improvement and industrial development of Pennisetum forages.

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.

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.

The seed yield and quality of the leguminous forage alfalfa （Medicago sativa L.） are significantly influenced by water and fertilizer management. This study aimed to investigate the effects of different water and phosphorus fertilizer treatments on seed yield and seed quality of alfalfa. The experiment was designed to combine treatments with different irrigation levels （600， 900， and 1200 m³·hm^-2） and phosphorus fertilizer rates （100， 200， and 300 kg·hm^-2）. Seed yield， yield components， soluble protein content， and starch content were measured. Additionally， multispectral information of 19 bands was acquired， and an nCDA-CNN model was constructed to evaluate the potential of multispectral image technology for seed detection under different water and fertilizer treatments. The results showed that the appropriate water and phosphorus fertilizer application significantly increased seed yield， protein content， and starch content （P<0.05）. Among all treatments， the combination of 600 m³·hm^-2 irrigation and 200 kg·hm^-2 phosphorus fertilizer achieved the highest seed yield （885.44 kg·hm^-2）， representing an increase of 287.96 kg·hm^-2 compared to the control. Higher soluble protein and starch contents of seeds were observed under the treatment with 600 m³·hm^-2 irrigation and 100 kg·hm^-2 phosphorus fertilizer. Path analysis indicated that the number of seeds per pod had a greater influence on seed yield. Multispectral image analysis revealed that the nCDA-CNN model accurately predicted alfalfa seeds subjected to different water and fertilizer treatments， with a recognition accuracy of 95%. This provides a high-throughput， non-destructive detection method for alfalfa seed production. Optimized water and fertilizer manag-ement can significantly enhance alfalfa seed production. Multispectral image technology combined with deep learning models holds important application prospects for quality detection and sustainable development in the grass seed industry.

To clarify the molecular characteristics of the WRKY gene family in highly cold-resistant Pennisetum alopecuroides and their functions in cold stress response， in this study we conducted systematic identification， phylogenetic analysis and cold stress-related expression pattern analysis of the WRKY gene family via combined genome-wide and transcriptome analyses. The results showed that a total of 104 PaWRKY genes with complete WRKY domains were identified， which were unevenly distributed on nine chromosomes. All the encoded proteins were hydrophilic， and most of them had poor in vitro stability and were susceptible to degradation. Based on phylogenetic analysis， the taxa were divided into seven subtribes， and Subtribe IIc comprises the most members， and ten core conserved motifs were predicted in total. Extensive homologous collinearity was found between this gene family and Oryza sativa subsp. japonica. The promoter regions of PaWRKY genes were enriched with numerous cis-acting elements responsive to abiotic stresses and phytohormones. Transcriptome data revealed that eight PaWRKY genes were differentially expressed under cold stress， including four upregulated and four downregulated genes， all of which harbored MeJA-responsive elements. This study clarified the molecular and evolutionary characteristics of the WRKY gene family in Pennisetum alopecuroides and screened out key cold stress-responsive genes， which laid a theoretical foundation for cold-tolerant molecular breeding of Pennisetum alopecuroides and evolutionary research of the WRKY gene family in Panicoideae.

Phytochrome A （phyA） is a key receptor that enables plants to perceive far-red light signals and regulates their growth， development， and stress responses. To investigate the function of the MsphyA gene and its molecular mechanism in response to abiotic stress in alfalfa （Medicago sativa L.）， this study conducted a bioinformatic analysis of the cloned MsphyA gene and detected its expression patterns under various abiotic stresses using qRT-PCR. Bioinformatic analysis revealed that the MsphyA gene has a CDS length of 3375 bp， encoding 1124 amino acids， and possesses typical PAS， GAF， and PHY motifs characteristic of the PHY family. Protein analysis indicated that MsphyA has a relative molecular mass of 124.3 kDa and a theoretical isoelectric point of 6.1. It is classified as an unstable， hydrophilic， non-secretory protein without a signal peptide and lacks transmembrane domains. Subcellular localization prediction suggested that MsphyA is localized to the nucleus. Phylogenetic analysis showed that MsphyA is most closely related to MtphyA from M. truncatula. qRT-PCR results demonstrated that salt， drought， acid， high-temperature， and low-temperature stresses all induced MsphyA expression. These findings indicate that MsphyA is widely involved in the abiotic stress responses in alfalfa. This study provides a foundation for further exploration of the MsphyA gene’s function.

Ethylene response factors （ERFs） are key regulatory proteins involved in plant responses to abiotic stresses. In this study， based on the genome data of Pennisetum purpureum， 53 members of the PpERF gene family were identified. The encoded proteins ranged from 191 to 1145 amino acids in length， with predicted isoelectric points ranging from 4.75 to 11.79 and molecular weights ranging from 20 536.11 to 124 866.3 Da. Among these genes， three were not mapped to the chromosomes， whereas the remaining genes were unevenly distributed across eight chromosomes. Phylogenetic analysis classified the PpERF genes into three evolutionary clades. Most PpERF proteins contained highly conserved Motifs 1， 2， and 4， and multiple stress-responsive cis-acting elements were identified in their promoter regions. Expression analysis showed that 11 PpERF genes exhibited spatiotemporal expression specificity under low-temperature stress， among which PpERF17， PpERF21， and PpERF32 were significantly upregulated after 24 h of cold treatment. Transient overexpression assays in tobacco further demonstrated that these three genes significantly enhanced plant tolerance to low-temperature stress. This study provides a theoretical basis for elucidating the molecular mechanisms underlying low-temperature responses in Pennisetum purpureum and offers potential candidate genes for the breeding of cold-tolerant forage grasses.

To clarify the key indicators for evaluating the cold tolerance of perennial forage Pennisetum spp.， a total of 42 Pennisetum germplasms were used as experimental materials in this study. Combining indoor low-temperature simulation with field trials， we analyzed the growth and physiological characteristics at the seedling stage and full growth period， overwintering rate， and their correlations of Pennisetum. The results showed that： Low-temperature stress significantly reduced seedling dry matter accumulation by 41.55% and plant height by 11.53%. The malondialdehyde （MDA） content in leaves and tiller nodes increased significantly by 90.43% and 108.48%， respectively. Osmotic regulation substances and antioxidant enzyme activities exhibited distinct responses to low temperature. A total of 9 indicators including soluble sugar and MDA contents in tiller nodes and leaves were screened out by principal component analysis to characterize cold tolerance at the seedling stage. Four accessions including ‘Sumu No.2’ ‘Guimu No.1’， Hybrid Pennisetum No.7 and Sweet Elephant Grass exhibited strong cold tolerance with an above 75% overwintering rate， while WQ Hybrid Pennisetum and Chinese Forage Grass showed weak cold tolerance with a below 50% overwintering rate.The overwintering rate was significantly negatively correlated with MDA content in tiller nodes， and significantly positively correlated with bud soluble sugar content. Soluble sugar and MDA contents were crucial indicators for characterizing the cold tolerance of Pennisetum. This study provides a theoretical foundation for the breeding and innovation of new Pennisetum germplasms with high cold tolerance.

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.

In order to explore the alleviation effect of exogenous plant growth regulators （ PGRs ） on the growth of reed canarygrass （Phalaris arundinacea L.）under salt， waterlogging and salt-waterlogging combined stress， reed canarygrass at tillering stage was used as material， and different concentrations of ethephon （ETH）， indole-3-acetic acid （IAA）， spermidine （Spd） and γ-aminobutyric acid （GABA） were applied under three stresses， and the related physiological indexes were determined. The results showed that all three stresses significantly inhibited the growth of reed canarygrass， and the application of PGRs could effectively alleviate the stress damage. Among them， the application of 80 mg·L^-1 ETH under salt stress had the best mitigation effect， the Pro content was significantly increased by 20.36% and the MDA content was decreased by 34.52% compared with the stress group. Under flooding stress， 60 mg·L^-1 ETH was the best， and the activities of SOD and CAT were significantly increased by 105.83% and 40.07%， respectively. Under combined stress， 10 mmol·L^-1 GABA had the best effect， chlorophyll content increased by 30.30%， MDA decreased by 43.75%， and CAT increased by 23.31%（P<0.05）. In summary， the application of PGRs can alleviate stress damage by enhancing osmotic adjustment and antioxidant capacity and reducing membrane lipid peroxidation， and the type and concentration of optimal regulators vary depending on the type of stress.

To screen surfactants suitable for foliar application on Leymus chinensis and capable of enhancing the absorption efficiency of 6-benzylaminopurine （6-BA）， five surfactants （Silwet 408，SDS，MES，DDM，orange） commonly used on hydrophobic leaves of gramineous plants were evaluated based on surface tension， critical micelle concentration， contact angle， and maximum stable retention. The results showed that the leaves of L. chinensis exhibited super hydrophobicity， and the apparent surface free energy at the heading stage was significantly lower than that at the regreening stage（P<0.05）. Polyether-modified silicone Silwet 408 exhibited the optimal performance， achieving the lowest surface tension at the critical micelle concentration （21.27 mN·m^-1） and complete spreading （contact angle <5°） at both growth stages， followed by orange peel essential oil. SDS and orange peel essential oil showed the highest retention at the regreening stage （36.16 mg·cm^-2） and heading stage （34.60 mg·cm^-2）， respectively. Therefore， Silwet 408 is recommended as the preferred surfactant， while orange peel essential oil serves as a green alternative at the heading stage. This study provides a theoretical basis and technical support for efficient delivery of foliar regulators in L. chinensis.

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.

To elucidate the physiological basis underlying provenance-dependent variation in seed germination of Acanthopanax senticosus， seeds collected from four locations in Heilongjiang Province， China-Acheng District （AC）， Mulan County （ML）， Gaoleng Town of Fangzheng County （GL）， and Tongbei County （TB）-were examined for phenotypic traits and germination performance， together with endogenous hormone dynamics during sand stratification and metabolomic profiles. The results showed that seeds from GL exhibited significantly higher germination rates and greater hundred-seed weight than those from the other provenances. In terms of hormonal regulation， GL seeds displayed the highest brassinosteroid （BR） content and the lowest abscisic acid （ABA） content at the late stage of stratification. Metabolomic analysis further indicated that prior to stratification， GL seeds were characterized by an accumulation of carbohydrates accompanied by reduced levels of stress-associated metabolites， whereas after stratification they preferentially enriched metabolites related to energy supply and biosynthetic processes. Weighted gene co-expression network analysis （WGCNA） revealed that the MEturquoise and MEred modules were positively associated with hundred-seed weight before stratification， while the MEyellow module was correlated positively with germination rate after stratification， highlighting key metabolite regulators. Collectively， these findings suggested that the superior germination potential of GL seeds was attributable to favorable seed traits， a more balanced hormonal status， and metabolically efficient reprogramming. This study provides a theoretical foundation for optimizing sand stratification practices and improving artificial propagation efficiency.

To investigate the salt tolerance of wild Annual bluegrass （Poa annua L.） germplasm resources in Northwest China， ten wild populations collected from Lanzhou （LZ）， Jiuquan （JQ）， Maiji （MJ）， Zhangye （ZY）， Huangzhong （HZ）， Wuwei （WW）， Baiyin （BY）， Jinchang （JC）， Xihe （XH）， and Zhouqu （ZQ） were used as experimental materials. A pot experiment was conducted to investigate the effects of different soil salinity levels （0.2%， 0.5%， 0.8%， and 1.1%） on plant growth， cell membrane system， and osmotic adjustment system of P. annua， and to comprehensively evaluate their salt tolerance. The results showed that with increasing salt stress， plant height， leaf length， leaf width， and potassium and calcium ion contents of the ten germplasms decreased gradually， whereas relative electrical conductivity， malondialdehyde content， free proline content， soluble sugar content， and sodium ion content increased. The overall salt tolerance of the germplasms was ranked as LZ>JQ>BY>JC>ZY>WW>HZ>ZQ>XH>MJ. At a soil salinity level of 0.8%， theLZ and JQ exhibited lower salt injury than the others， indicating stronger salt tolerance， and suggesting their potential for cultivation in saline soils of Northwest China.

Elephant grass （Pennisetum purpureum） and hybrid Pennisetum are high-quality forage grasses with remarkable biomass potential. However， evaluation of their adaptability and agronomic performance in Northern China remains insufficient. This study aims to systematically evaluate the agronomic traits of 80 Pennisetum accessions in Beijing and screen the excellent germplasm suitable for northern cultivation. Seven key agronomic traits， including plant height， leaf length， leaf width， tiller number， stem diameter， fresh weight， and dry weight were measured for the 80 accessions. Then coefficient of variation （CV） analysis， correlation analysis， principal component analysis （PCA）， and subordinate function analysis were employed for comprehensive evaluation. The results showed that the 80 accessions exhibited rich genetic diversity. The CVs of the seven traits ranged from 10.97% to 78.77%， with dry weight （78.77%） and fresh weight （69.85%） exhibiting the highest variation， this indicates that there are significant differences in biomass-related traits among different genotypes. By correlation analysis， individual that leaf length and leaf width， as well as fresh weight and dry weight， were both highly significantly positively correlated （P < 0.01）. Principal component analysis （PCA） revealed that four principal components accounted for a cumulative contribution rate of 89.70%， primarily representing biomass factors， plant architecture factors， and tillering factors. Based on the membership function values， the top 10 accessions with superior comprehensive performance were identified. P.americanum×P. purpureum ‘Sumu No.4’，P. purpureum ‘Chuanyu No.1’ ， P. purpureum ‘Zise’ ， P. purpureum ‘Huanan’， P.americanum×P. purpureum ‘No.11’， P. purpureum ‘No.31’，P. purpureum ‘Guiminyin’ ， P.americanum×P. purpureum ‘CHP31’，P. purpureum ‘No.10’ and P. purpureum ‘Dehong’. This study provides high-yielding Pennisetum germplasm for forage cultivation and breeding in Northern China.

The relationship between biodiversity and ecosystem functioning has become a central issue in the fields of climate change and biodiversity conservation. The Qinghai-Tibet Plateau represents a globally typical ecologically fragile region， and with the intensification of global climate change， the structure and functioning of alpine meadow ecosystems are undergoing significant alterations. In this study， open-top chamber warming experiments were conducted to comprehensively assess plant species diversity and multiple ecosystem functions. Ecosystem multifunctionality was quantified using the averaging method to explore the relationships among simulated warming， species diversity， ecosystem functions， and multifunctionality. The results showed that warming suppressed the accumulation of aboveground and belowground biomass， while Margalef index， Simpson index， and Shannon-Weiner index decreased significantly （P<0.05）. Redundancy analysis indicated that ecosystem multifunctionality was significantly positively correlated with Margalef index， Shannon-Weiner index， and Simpson index （P<0.05）， with improvements in these indices accompanying enhancements in ecosystem functioning. Among these， species richness appeared to be a more critical influencing factor compared with species evenness and dominance. This study provides an important theoretical reference for understanding the responses and adaptive mechanisms of alpine meadow ecosystems under global climate change on the Qinghai-Tibet Plateau.

To optimize the alfalfa-maize intercropping system in the Hexi Irrigation District and identify the suitable maize cultivars， 10 maize （Zea mays L.） cultivars were used to compare their agronomic traits， yield performance， and nutritional quality under sole-cropping and intercropping conditions. Structural equation modeling and a multi-criteria decision-making model were further employed for integrated analysis. The results showed that cultivar， cropping pattern， and their interaction had highly significant effects on plant height， stem diameter， effective plant density， fresh weight per plant， and dry matter yield （P<0.01）. Under intercropping， ‘Jinzhangye 1706’ had the highest dry matter yield （27.12 t·hm^-2）. ‘Tunyu 168’ had the highest ear fresh weight （522.33 g）， and its fresh weight per plant reached 1.32 kg. ‘Ganyu 23’ had the highest number of green leaves and the highest crude protein （CP） content （10.77%）. Structural equation modeling indicated that the pathways by which agronomic traits affected dry matter yield and relative feed value （RFV） differed between planting patterns. Based on the multi-criteria decision-making results， cultivar selection for the intercropping system should comprehensively consider agronomic traits， yield and nutritional quality. Among the tested cultivars， ‘Ganyu 23’ ‘Jinzhangye 1706’ and ‘Tunyu 168’ can be selected as optimal cultivars for the alfalfa/maize intercropping system in this region.

To reveal the regulatory mechanisms of different utilization methods on the relationship between plant diversity and soil phosphorus in temperate meadow steppe， this study selected the grassland within the Huihe National Nature Reserve as the object and systematically compared the response characteristics of plant diversity indicators and surface soil phosphorus activation coefficient （PAC） under grazing， mowing， and enclosure modes. The results showed that plant diversity responded significantly to the utilization methods. The number of species， Margalef index， Simpson index， and Shannon-Wiener index under mowing were significantly higher than those under enclosure and grazing （P<0.05）， and enclosure was significantly higher than grazing； the Pielou evenness index was only significantly higher under mowing than grazing （P<0.05）. Soil phosphorus and its availability varied depending on the utilization methods. The content of total soil phosphorus （TP） under mowing was significantly higher than that under enclosure and grazing （P<0.05）； grazing significantly increased the content of surface soil available phosphorus （AP） and PAC （P<0.05）. The relationship between plant diversity and soil phosphorus was regulated by the utilization methods. Under enclosure， AP was significantly negatively correlated with all diversity indices， and PAC was significantly negatively correlated with most indices； under grazing， TP was significantly negatively correlated with the Margalef index， while significantly positively correlated with the Pielou index， and AP was only negatively correlated with the Margalef index； under mowing， there was no significant correlation between soil phosphorus indicators and plant diversity indices. In summary， the utilization methods not only independently affected plant diversity and soil phosphorus availability， but also regulated the relationship between them.

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.

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.

Based on multi-year， multi-site field trials combined with physiological and photosynthetic measurements， in this study we evaluated the cold tolerance and production adaptability of a new Pennisetum purpureum line ‘Yunmu No.1’（YM-1）， in comparison with two local predominant cultivars， P. purpureum ‘Dehong’（DH） and P. purpureum ×P. typhoideum ‘Reyan No.4’（RY-4）. The results indicated that the cold tolerance of the tested materials， in descending order， was YM-1>DH>RY-4. YM-1 had the lowest semi-lethal temperature （LT₅₀） of -5.413℃. Under low-temperature stress， its superoxide dismutase （SOD） activity increased significantly by 237.12%， while malondialdehyde （MDA） content increased only marginally by 1.25%， indicating that it primarily responds to low temperature through an antioxidant mechanism. In contrast， DH mainly responded to low temperature by accumulating osmotic adjustment substances， including soluble sugar （+76.77%） and proline （+60.24%）. RY-4 exhibited weak responses in both antioxidant and osmotic adjustment mechanisms， with an MDA increase of 43.07%. The freezing injury index during the first-frost period was consistent with the above physiological ranking. At an altitude of 2350 m， YM-1 showed the highest sprouting rate （50.4%； i.e.， the proportion of stumps with newly sprouted tillers） and regreening rate （43.0%）. Its three-year average hay yield was 6.1% and 11.3% higher than those of DH and RY-4， respectively. In conclusion， ‘Yunmu No.1’ possesses both strong cold tolerance and high and stable yield potential， making it suitable for cultivation in complex environments below 2000 m elevation on the Yunnan Plateau. A comprehensive evaluation method based on LT₅₀， MDA content， SOD activity， field freezing injury phenotype， and natural overwintering capacity can be used for the systematic identification of cold tolerance in Pennisetum purpureum.

To screen salt-tolerant Medicago sativa L. germplasm， 43 alfalfa hybrid F₂ materials were treated with four NaCl concentrations （0%， 0.3%， 0.6%， and 1.2%）. Agronomic traits， including germination potential， germination rate， fresh weight， shoot length， and root length， were measured， and key physiological indicators such as proline and malondialdehyde were analysed. Principal component analysis， membership function method， and cluster analysis were used to comprehensively evaluate salt tolerance at the germination stage. The results indicated that 0.6% NaCl was suitable for screening salt tolerance at this stage. Germination rate， root length， shoot length， and relative proline content （R-Pro） were identified as core indicators for evaluation. Seven highly salt-tolerant materials—GW141， GD131， GZ21， GW71， GD111， GD171， and GD301—were selected， which exhibited both agronomic advantages （“high germination rate and strong root development”） and physiological resistance （“strong osmotic adjustment and weak membrane lipid peroxidation”） under salt stress， providing valuable candidates for salt-tolerant breeding and saline-alkali soil improvement.

This study aimed to elucidate the effects of varying grazing intensities on soil active organic carbon fractions and their environmental driving mechanisms in the typical steppe of Xilingol League， which could provide empirical support for carbon management strategies in grassland ecosystems. Three grazing treatments—no grazing （CK）， moderate grazing （MG）， and heavy grazing （HG）—were established in the experimental area using a completely randomized block design with five replicates per treatment. Soil physicochemical properties， soil organic carbon （SOC）， and its active fractions were quantified and analyzed. Compared to CK， MG significantly decreased the contents of particulate organic carbon （POC） and microbial biomass carbon （MBC）， but significantly increased the easily oxidizable organic carbon （EOC） content. The HG treatment significantly reduced the contents of POC and dissolved organic carbon （DOC）. Furthermore， POC and MBC contents under MG were significantly higher than those under HG. SOC exhibited a highly significant positive correlation with all its active fractions （P<0.05）. Soil water content （SWC） and total nitrogen （TN） were identified as the key factors influencing SOC and its fractions. Overall， grazing reduced the contents of SOC and its active fractions in the typical steppe. Therefore， avoiding heavy grazing is recommended. Incorporating soil moisture regulation and moderate nitrogen supplementation during pasture utilization can enhance soil carbon sequestration， thereby maintaining soil quality and carbon pool functionality.

Clarifying the effects of different vegetation types on soil quality is of great significance for maintaining ecological stability in the hilly-gully region of the Loess Plateau. This study was conducted in the Anjiapo watershed， Dingxi City， Gansu Province as an example. Five vegetation types were selected， including spruce forestland， sea-buckthorn forestland， alfalfa grassland， wheat cropland and abandoned bare land. A total of 18 soil indicators were measured in the 0-20 cm soil layer. Soil quality indices were calculated based on the total data set， minimum data set， and revised minimum data set， combined with linear and non-linear scoring methods. The results showed that spruce forestland had the highest SQI of 0.53， which was 35.9% higher than that of abandoned bare land. The revised minimum data set combined with the linear scoring model （SQI-LRM） exhibited the strongest explanatory power. Partial least squares structural equation modeling revealed that different vegetation types primarily affected soil biological properties through their influence on soil chemical properties. Random forest combined with multiple linear regression analysis revealed that different vegetation types mainly drove soil quality by regulating soil pH， which in turn influenced protease activity. In conclusion， spruce forestland can significantly improve soil quality， and the SQI-LRM model can provide a quantitative basis for soil quality improvement and sustainable ecosystem development in the study area.

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.

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.

To clarify the effects of the median lethal concentrations（LC₅₀） of lambda-cyhalothrin and thiamethoxam on the growth， development and reproduction of Frankliniella intonsa resistant populations in alfalfa fields， two field-resistant populations （YLC and MS） from Ningxia were used as test materials. Stress treatments were conducted based on laboratory toxicity assays， and the effects of the two insecticides on the fecundity， developmental duration， body length， body width， adult longevity and survival rate of the offspring of Frankliniella intonsa were investigated. The results showed that under the stress of median lethal concentration of the two insecticides， the fecundity of F₁ adults decreased significantly； the developmental duration of F₂ eggs and first-instar nymphs was significantly prolonged； the body length and body width of F₂ first-and second-instar nymphs were significantly reduced； the longevity of F₂ adults was significantly shortened； and the survival rate of F₂ at each developmental stage was significantly decreased. This study confirmed that the median lethal concentration of lambda-cyhalothrin and thiamethoxam could significantly inhibit the reproduction， growth， development and survival of Frankliniella intonsa populations， providing important technical support for the scientific management of field insect pests.

Herbicide prevention and control of weeds in the field is a common weed control method for field crops. At present， China’s Ministry of Agriculture and Rural Affairs has not yet passed the registration of any herbicide on oats. Therefore， it is of great reference and guiding significance to explore the effects of phenoxycarboxylic acid （2，4-D derivative） herbicides on weed control and oat grass yield in oat fields. In this study， the ‘Zhongcao No.16’ oat variety was used as the background oat. By setting up 8 different components， dosage treatments and a blank control treatment， foliar spraying was carried out at the jointing stage of oats. The fresh grass yield of oats and the control effect of weed plant numbers and fresh weight were measured at the milky stage of oats. The results showed that the four phenoxy carboxylic acid herbicides had different degrees of control effects on the number and fresh weight of quinoa and Artemisia， but had no control effect on gramineous weeds， and had a certain yield increase effect on oat fields. On the whole， 2.5 mL and 5 mL 2，4-D dimethylamine salt， 4 mL and 8 mL 2，4-D isooctyl ester were suitable for weed control of quinoa and artemisia in oat field， and had a certain yield-increasing effect on oat.

This study aimed to evaluate the effect of Lactobacillus plantarum （LP） addition on the silage quality of forage oat （Avena sativa） varieties grown in different regions， thereby providing a theoretical basis for the promotion of new forage oat varieties and the optimization of silage processing techniques. Three oat varieties， ‘Zhongxuyan No.1’ （a new strain）， ‘Qinghai Sweet Oat’， and ‘Qingyin No.2’， were grown in Qinghai and Ningxia. After harvesting at the milk stage， the oats were ensiled under identical conditions with either distilled water （control） or LP treatment for 60 days， after which the silage samples were subjected to sensory evaluation as well as nutritional and fermentation quality analyses. The results showed that LP addition significantly improved the sensory scores and V-Score grades. Nutritional analysis revealed that the crude protein （CP） and ether extract （EE） contents of ‘Zhongxuyan No.1’ silage were significantly higher than those of the other varieties （P<0.01）. Fermentation analysis demonstrated that region significantly affected pH （potential of hydrogen）， lactic acid （LA）， butyric acid （BA）， and the NH₃-N∶TN （ammonia nitrogen∶total nitrogen） ratio in oat silage （P<0.01）， and the pH and BA contents of ‘Zhongxuyan No.1’ were significantly lower than those of the other varieties （P<0.01）. A comprehensive comparison of treatments indicated that LP addition was more beneficial for improving silage fermentation quality. Among the three varieties tested， ‘Zhongxuyan No.1’ performed well in both regions and was identified as the most suitable variety for silage.

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 investigate the effects of intercropping ratios and cutting periods on forage production performance in a rapeseed-oat mixed cropping system， this trial measured and analyzed forage yield and quality indicators across nine mixing ratios and three cutting periods for the rapeseed （‘Qingyou No. 21’）-oat （‘Lena’） system. Results indicated that dry hay yields at the late rapeseed flowering stage （A₂） and the rapeseed pod milk stage （A₃） were significantly higher than at the peak rapeseed flowering stage （A₁） （P<0.05）. The relative feed value at A₃ was significantly higher than at A₁ and A₂ （P<0.05）. At A₃， the 5∶5 rapeseed-oat mixture （A₃R₅O₅） exhibited the highest land equivalent ratio of 2.21. TOPSIS multi-criteria decision analysis indicated that during A₃， the 7∶3 rapeseed-oat mixture （A₃R₇O₃） achieved the highest fit index of 0.75. This treatment exhibited comparatively high hay yield （454.16 kg‧hm^-2） and land equivalent （2.16）， with lower acid-detergent fiber （69.19%） and neutral-detergent fiber （38.64%） content. This constitutes an agronomic practice suitable for promotion within the study area.

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.

To optimize the lodging-resistant cultivation scheme for forage sweet sorghum （Sorghum bicolor （L.） Moench cv. ‘Jingxi’） in Kashi， Xinjiang， a split-plot design was used with two plant spacings （Z₁： 10 cm， Z₂： 20 cm） and six row spacing configurations （equal row spacing： 30， 40， 50 cm； wide-narrow row spacing： 20+40， 30+50， 40+60 cm）， resulting in 12 plant-row configuration treatments. Agronomic traits， stem chemical composition， stem mechanical strength， and field lodging rate were measured over two harvests. The results showed that plant–row configuration significantly affected lodging-related traits. Across both harvest s， equal row spacing of 50 cm and wide-narrow row spacing of 40+60 cm exhibited lower lodging rates. Among these， the equal row spacing of 50 cm （H₅） treatment produced the highest stem mechanical strength and the best accumulation of fiber components. Correlation analysis revealed fundamentally different lodging resistance mechanisms between the two stubbles： lodging resistance in the first stubble depended on the synergistic enhancement of stem diameter， wall thickness， and mechanical strength， whereas that in the second stubble relied on the accumulation of stem fiber components （acid detergent fiber， neutral detergent fiber， lignin） to maintain strength. Comprehensive evaluation of both stubbles indicated that the H5 configuration （equal row spacing of 50 cm）， whether combined with Z₁ or Z₂ plant spacing， significantly improved the overall lodging resistance of ‘Jingxi’ and was the optimal pattern under the experimental conditions. These findings provide a specific technical scheme and theoretical basis for lodging-resistant cultivation of forage sweet sorghum in arid regions.

In order to overcome the bottleneck of low seed yield during its propagation process， this study investigated the effects of foliar application of phosphorus （P）， potassium （K）， and zinc （Zn） on the seed yield of Kengyilia thoroldiana. Four gradient levels of potassium dihydrogen phosphate （KH₂PO₄）， including 30 kg·hm^-2 （A₁）， 60 kg·hm^-2 （A₂）， 90 kg·hm^-2 （A₃）， and 120 kg·hm^-2 （A₄）， were combined with a fixed amount of zinc sulfate （ZnSO₄） （6.25 kg·hm^-2） for foliar co-application. Key agronomic traits， photosynthetic characteristics， seed yield， and nutritional quality were systematically evaluated. A membership function analysis was employed to conduct a comprehensive assessment of all treatments， enabling the identification of the optimal fertilization combination. Results showed that compared with control （CK）， the A₃ treatment significantly increased the grass height， reproductive stem height， and flag leaf area of Kengyilia thoroldiana by 44.45%， 45.85%， and 45.15%， respectively. In terms of photosynthetic characteristics， the net photosynthetic rate and SPAD value of the flag leaf under the A₃ treatment were 30.72% and 54.10% higher than those under CK， respectively. Regarding seed yield， the A₃ treatment produced the highest yield， 593.23 kg·hm^-2， which was 40.68% greater than CK. Principal component analysis （PCA） and membership function analysis revealed that the A₃ treatment had the highest comprehensive evaluation D value （0.93）， followed by the A₂ treatment. The CK treatment exhibited the poorest performance in all evaluated parameters. In conclusion， foliar applications of KH₂PO₄ and ZnSO₄ enhanced the growth and development of Kengyilia thoroldiana， improved photosynthetic performance， and increased seed yield. The combined foliar application of 90 kg·hm^-2 KH₂PO₄+6.25 kg·hm^-2 ZnSO₄ demonstrated the most effective outcome， providing a scientific basis for optimizing seed production in Kengyilia thoroldiana.