In this experiment， the effects of single application of organic fertilizer and mixed application of organic fertilizer on the restoration of degraded natural mowing land were evaluated from the perspective of vegetation-soil-microorganism. The natural mowing land in Altay Mountains was used as the object of study. Three fertilization measures， single application of organic fertilizer （M）， mixed application of organic fertilizer and biological fertilizer （M+NY）， mixed application of organic fertilizer and compound fertilizer （M+NPK）， were used to explore the responses of grassland vegetation-soil-microorganism to fertilization. The results showed that fertilization significantly increased grassland community height， biomass， soil organic matter content， available nitrogen， available phosphorus， available potassium content and electrical conductivity （ P<0.05）， and significantly reduced soil pH value （ P<0.05）. There were significant differences in the richness of 5 phyla in soil bacteria （ P<0.05）， and there were significant differences in the richness of 2 phyla in soil fungi （ P<0.05）. The grey system correlation degree showed that compound fertilizer + organic fertilizer had the best effect on promoting vegetation growth， improving soil nutrients and increasing the number of microorganisms， and had a rapid recovery effect on the vegetation-soil-microbial system of reseeding natural mowing land. The results of the experiment provide theoretical basis， data support and technical support for the production and restoration of organic fertilizer single application and organic fertilizer mixed with other fertilizers in reseeding natural mowing land.

To explore the relationship between root characteristics and productivity of alfalfa in early growth stage,in this study,a field experiment was conducted with alfalfa ‘Gannong NO. 7’,‘Gannong NO. 3’,‘LW6010’ and ‘Longdong’ as experiment materials,and two treatments of no nitrogen application and nitrogen application (103.5 kg·hm ^-2) were set to study the performance and root characteristics of the 1 ^st cut alfalfa cut in the planting year and their correlation. The results showed as follows:regardless of nitrogen application,plant height,yield,taproot length,root volume,root surface area,root nodule number per plant,nodule weight per plant,crude protein content and relative feeding value of ‘LW6010’ were the highest,and the plant height,yield,taproot length,root surface area,crude protein content and relative feeding value of ‘LW6010’ were significantly higher than those of ‘Longdong’ alfalfa (P<0.05). The agronomic traits and quality of all varieties were better than that without nitrogen application. According to the correlation analysis,the root characteristics of alfalfa were positively correlated with yield,The root length,root volume,root surface area and nodule weight were positively correlated,and the number of nodule was positively correlated. Therefore,improving the taproot length,root surface area,root volume and nodule characteristics in the early growth stage of alfalfa will improve its yield.

To explore the planting methods of high yield and quality with efficient use of nitrogen fertilizer in tall fescue ( Festuca arundinacea L.) in the Longdong area,two years field trials were conducted by using three nitrogen application rates of 0 kg·hm ^-2(N1),80 kg·hm ^-2(N2)and 160 kg·hm ^-2(N3). In addition,three mowing frequencies including mowing every 25 days (M1),every 50 days (M2),and every 75 days (M3) were set under each nitrogen rate. The results showed that the annual hay yield,crude protein yield,and nitrogen uptake was significantly higher for N2 and N3 treatments than that of N1 in both years. Compared to N1,the average hay yield of N2 and N3 treatments was increased by 13.5% and 15.5%,and the average crude protein yield increased by 21.34% and 25.25%. The N2 treatment significantly improved nitrogen use efficiency compared to N3 treatment. Moreover,the hay yield and crude protein yield of M2 treatment were higher than that of M3 treatment,but the difference between the two treatments was not significant. Compared to M2 and M3 treatments,M1 significantly decreased the content of acid detergent fiber and neutral detergent fiber,which obviously increased the relative feed value. Compared to M3 treatment,M2 significantly improved the nitrogen uptake and nitrogen use efficiency. Among all the treatments,N3M2 treatment has the best comprehensive evaluation of nutritional quality and can be considered as a best management measure for improved forage quality in tall fescue,while N2M2 treatment obtained higher hay yield and nitrogen use efficiency,and can be adopted as a suitable management strategy for efficient use of nitrogen fertilizers.

Arbuscular Mycorrhizal Fungi （AMF） play an important role in maintaining the function of grassland ecosystems. Grazing is one of the main utilization modes of grasslands， which has a profound effect on the symbiotic relationship between plants and AMF. However， the regulatory effects of grazing on the Stipa breviflora-AMF symbiosis and its driving mechanisms remain unknown. This study， conducted in the S. breviflora grassland of Inner Mongolia， examined the effects of different grazing intensities—no grazing， light grazing （LG）， moderate grazing （MG）， and heavy grazing （HG）—on the AMF colonization rate in S. breviflora roots. The results revealed a significant decline in the AMF colonization rate with increasing grazing intensity. The colonization rates were 65.89%， 59.89%， 52.89% and 41.33% under different grazing intensities， respectively. Spore density and hyphal length density decreased with increasing grazing intensity. In addition， increased grazing intensity led to longer total root length and smaller root diameter in S. breviflora， along with higher soil density and pH but lower soil organic carbon and available phosphorus. However， soil moisture and nitrate nitrogen content peaked under light grazing. Soil nitrate nitrogen and available phosphorus were identified as the primary factors influencing the reduction in AMF colonization. In conclusion， grazing negatively affects AMF colonization in desert steppes by decreasing nitrogen and phosphorus nutrient effectiveness in the soil. This study provides empirical data and theoretical insights that support the development of sustainable grazing management strategies to maintain the health and resilience of desert steppe ecosystems.

In order to study the effects of different clipping periods and heights on Alfalfa quality, several investigations on the effects of different clipping periods and heights on Alfalfa quality were launched. Golden Queen Alfalfa and Sandeli Alfalfa cropped with the proportion of 1:1 were Chosen as experiment materials. The production and the nutritional content of hay forage at different clipping heights and phenophases were determined. The results showed that compared with harvested Alfalfa in early florescence, the production of fresh forage and hay forage clipped when Alfalfa grew to 80 cm height, were 2510.4 kg·hm^-2 and 807.3 kg·hm^-2 greater, respectively. CP content and RFV value were 2.45% and 1.35 higher, respectively. Taken growth height as the standard, clipping at 80 cm height could get the best quality and production of Alfalfa forage in Chifeng region.

This study was aimed to provide scientific guidance for the management and utilization of alpine mountain meadow. A typical area of the alpine meadow ecosystem on eastern Qinghai-Tibet Plateau (branch veins of Ri-Yue Mountain) was selected as the sampling site. We used redundancy analysis and Variance partitioning analysis to determine the main factors (slope aspect,altitude and soil moisture) on plant diversity distribution in 39 quadrats of the small-scale mountain. The result showed that the species richness on the shady aspect was the highest followed by the sunny aspect,and that on the ridge was the lowest. Species richness in all the three plots at medium altitude was the highest. The soil moisture content on the shady aspect was the highest and that on the ridge was the lowest. The variance partitioning analysis showed that altitude had the highest contribution rate to soil moisture,slope aspect had the highest contribution rate to plant abundance. Most plant were distributed on the shady aspect and at medium altitude. Therefore,to precisely and efficiently utilize small-scale alpine meadow the difference of vegetation distribution pattern caused by slope direction must be considered.

In order to clarify the vertical distribution characteristics and influence factors of soil dry layer under different land use types in the mountainous area of southern Ningxia,the dry layer initial depth (DSLFD),dry layer thickness (DSLT),desiccation index (SDI) and soil water relative deficit index (CSWDI) were used to quantitatively evaluate the condition of 0~600 cm soil dry layer,and the main affecting factors were determined by typical correlation analysis. The results showed that the average soil water content under forest land,shrub land,grassland,abandoned farmland and agricultural land were 11.46%,11.79%,14.97%,14.52% and 14.66%,respectively. There were no dry soil layers in grassland,abandoned farmland and agricultural land. The forest land and shrub land showed moderate and mild drying degree,respectively. DSLT on forest land and shrub land was 440 cm and DSL-SMC (Desiccated soil layer-soil moisture content,DSL-SMC) were 9.10% and 9.93%,respectively. The thickness of intense,severe,moderate and mild drying layer under forest land was 40,200,180 and 20 cm,respectively. The thickness of severe,moderate and mild drying layer under shrub land was 80,240 and 120 cm,respectively. The CSWDI of 60~600 cm soil layers under different land use types were forest land (0.58) > shrub land (0.46) > abandoned farmland (-0.03) > grassland (-0.08). The redundancy analysis showed that land use type,and different soil and vegetation nutrient condition were the main factors affecting the soil desiccation. The results indicated that different degrees of dry soil layers could be found under forest land and shrub land in the mountainous area of southern Ningxia. Some measures could be taken to promote the restoration of vegetation and the sustainable development of the soil and water environment,such as tree pruning,soil preparation and planting density.

In order to improve the yield and quality of forage, and to create the most benefit for Bothriochloa ischaemum, this experiment used randomized block design with the urea, ammonium sulfate and calcium ammonium nitrate fertilizers, with nitrogen levels at 0, 30, 60, 120 and 240 kg N·hm^-2 for the cultured B. ischaemum. The results showed that the highest hay-yield was 13.5 t·hm^-2 at 60 kg N·hm^-2 of urea, followed by AS-N₆₀ and CAN-N₁₂₀. In term of crude protein (CP), crude fat (EE), neutral detergent fiber (NDF), and acid detergent fiber (ADF) of B.ischaemum, the best performance were at the U-N₆₀ level when applying U, and at the AS-N₁₂₀ level when applying AS. When CAN was applied, the contents of EE and NDF were optimum at 60 kg N·hm^-2, while the contents of CP and ADF were the best at 120 kg N·hm^-2. By combining yield, nutritional quality and economic benefits, it is most appropriate to apply 60 kg N·hm^-2 of urea.

In this paper, the contents of 13 chemical elements (N,P,K,Ca,Mg, Mn, Zn,Cu,Co,Cr,Ni,Cd,Pb) in different plant types of Natural Grassland Reserve of Wutai Mountain were studied.The contents of 13 chemical elements in various plant species were great difference.The average contents of N and Ca were higher than 10g/kg; P, Mg, and K ranged between 1 and 8 g/kg, Mn, Zn, Cu and Cr between 10 and 100 mg/kg,Ni and Pb from 1 to 9 mg/kg; Co and Cd were less than 1 mg/kg.The plants in studied area were of high nutrition levels, which were able to meet the ha requirements of the animal, particularly the plants in the subalpine meadow were highly valuable for feeding animal.

Naturally occurring arbuscular mycorrhizae (AM) are the result of long-term evolution between plant and soil fungi. This symbiosis role can promote fungi and host plants to have an important adaptability. In recent years, the interaction mechanisms of AM fungi and host plants, as well as the establishment of AM symbiosis have been widely studied. In this review, molecular signaling pathways of AM symbiosis are discussed. The signal transduction pathway in asymbiotic stage, the early stages of plant-fungus interactions and the maintenance of symbiotic phase are general summarized.

Grazing is the most important use of natural grassland,and its effects on grassland are mainly feeding,trampling and excretion. Different types of livestock have different grazing behaviors,and their effects on grassland are also different. In order to study the effect of mixed grazing of cattle and sheep on the constructive species of the Stipa sareptana grassland,following indoor experimental treatments were designed in this study:control (CK_s),addition of cow dung + mowing (to simulate cow single-grazing,CG_s),adding sheep dung + no mowing (to simulate sheep single-grazing,SG_s),adding cow and sheep dung + mowing (to simulate cow and sheep mixed grazing,MG_s). The root and shoot growth dynamics of Stipa sareptana var. krylovii. were determined from June to December. The results showed that the height of Stipa sareptana var. krylovii. under the MG_s treatment was higher than SG_s or CG_s,the number of its tillers was moderate,but the root production was relatively low;Based on these,we can draw a conclusion that mixed grazing with cattle and sheep is more likely to increase the productivity of Stipa sareptana var. krylovii steppe. Dynamic observations found that the root of Stipa sareptana var. krylovii under different treatments were mainly produced in the growing season,and roots mainly died in the non-growing season.

In this study,agronomic characters related to the adaptability of 30 different oat varieties in Tianzhu,Gansu Province including phenological phases,hay yield and ten major characters were investigated. The results showed that only 7 varieties completed the growth period in Tianzhu. Most of the varieties only reached milking stage. the highest hay yield was Yan wang(192.87 kg·100m ^-2),The results of path analysis showed that the panicle number,leaf width and plant height area are the biggest factors affecting hay yield in Tianzhu;Principal component analysis of nine characters related to adaptability indicated that the contribution rate of four principal component factors reached 81.33%. Accession Dinyan No.2 was the most suitable variety in the region of Tianzhu,Gansu Province with the highest integrated score compared to other tested varieties.

Biological soil crusts (BSCs) are special complexes composed of lower plant, microorganism (bacteria, fungi) and surface soil fine particles bonded by their exuding mucilaginous material, which are widespread in the semi-arid regions all over the world. In many literatures, BSCs are known as ecosystem restoration engineer, it not only makes great contribution to nutrient fixation (Carbon, nitrogen and phosphorus) and soil enzyme activity, but also plays vital roles in seed germination and seedling survival by regulating hydrological process of soil surface (precipitation infiltration, surface runoff, evaporation and other processes), which include autotrophic and heterotrophic organisms. The autotrophic organisms mainly consist of algae, lichen and moss, and heterotrophic organisms are composed of bacteria, microscopic fungi, etc. The classification of BSCs can be divided into three categories: algae, lichen and moss crust based on the dominant species and succession direction of BSCs. The formation, development and structure of BSCs are affected by human activities and climate disturbances, but little attention have devoted to the monitoring and management of BSCs. In this study, the simple ratio index (SRI) and normalized difference vegetation index (NDVI) were summarized to monitor the morphology of BSCs. Furthermore, the effect of BSCs succession and its ecological function on arid and semi-arid ecosystems under different utilization ways and intensity were also discussed, which laid a foundation for a further understanding of the surface process of arid and semi-arid areas and promoting the restoration of degraded ecosystem.

Artemisia halodendron is an important wind-breaking and sand-fixing plant in northeast China. In our study,the anatomical structures of the leaves and stems of A.halodendron were observed by the paraffin section technique in different regions of Inner Mongolia. Based on the measurements,using ANOVA to compare the differences among different regions,the dominant climatic factors affecting anatomical quantitative characteristics were obtained by stepwise regression. The results showed that:1) Anatomical structures characteristics of A.halodendron are as follows:isolateral leaf;one layer epidermal cells;ring-shaped palisade tissue,arranged closely;developed vascular bundle, One layer stem epidermal cells;outer tough infinite vascular bundle,annular arrangement;developed pith. 2)The thickness of upper epidermal cuticle and stem cortex of A.halodendron from the northern Hulunbeier sandy land was significantly higher than that from the Horqin sandy land and the diameter of pith and stem cortical had similar trends. 3)The thickness of palisade tissue and the diameter of stem sieve tube increased with the decrease of precipitation in growing season,and the upper epidermal cuticle,pith diameter and stem vessel diameter increased with the decrease of effective temperature,showing the adaptability to water and temperature. The results provided basic data for the ecological adaptability research of A.halodendron population under different climatic conditions.

In order to provide the evidences for further research of alfalfa ( Medicago sativa L.), the substantial studies of alfalfa root biomass in China, the United States and Canada were summarized. The vertical distribution pattern of alfalfa root biomass and its dominant factors in different natural regions were discussed. Factors included the depth of soil layer, underground water level, soil properties, fertilization, irrigation, cutting, mixture sowing, cultivar, and growth period. The distribution of alfalfa root biomass in topsoil was increased as the depth of soil layer lessened and the level of underground water increased, or soil conditions became worse. Fertilization, especially phosphate fertilizer increased the distribution in submerged soil. Different irrigation amount, frequency and pattern had the complex effect on vertical distribution of alfalfa root biomass. Less single irrigation amounts and higher irrigation frequency increased the distribution of alfalfa root biomass in topsoil. Higher cutting frequency decreased the distribution in submerged soil. Mixture sowing with graminous plants increased the distribution of alfalfa root biomass in topsoil. Alfalfa cultivars have different vertical distribution patterns of root biomass. The soil layer of vertical distribution became deeper as the plants grew. Alfalfa root biomass decreased exponentially with soil depth increasing. Under normal conditions, the distribution ratios of alfalfa root biomass in the 0~30 cm depth were about 60% to 90%, and in the 0~60 cm depth were about 65% to 95%.

To understand the reproductive characteristics and adaptation strategies of Caragana roborovskyi in the arid desert. The breeding tendency, clonal growth and ramets characteristics of C. roborovskyi in the Alshan desert region of the Inner Mongolia Plateau were studied. Results showed that C. roborovskyi propagated not only by asexual reproduction but also by sexual reproduction. The proportion of asexual reproduction (95.8%) was significantly higher than that of sexual reproduction (4.2%). C. roborovskyi produced ramets mainly by sprouted root and established clonal architecture known as "Guerilla". Overall, C. roborovskyi adapted to both arid and barren environment of Alshan desert region by "Guerilla" clonal propagation and well-developed root system which determined it as the dominant species in the desert.

The composition and features of spermatophytes were analyzed to explore the origin and evolution of flora in the steppe desert area of Wuhai.Results based on a three-year survey with ample relevant data suggest that the spermatophyte distribution in the steppe desert area include 72 families,267 genera and 565 species,of which 560 angiosperm species(including 41 varieties) belong to 265 genera and 70 families.The number of angiosperms account for 99.1% of all species.The multi-specific family,oligo-specific family,oligo-specific genera and mono-specific genera are the main source of flora complexity.The dominance of the multi-specific family and oligo-specific genera were evident in the number of species.In most cases,though mid-specific family,mid-specific genera and mono-specific family are not the main part,they have an influence on the structure of flora and vegetable composition.Geographic elements of the flora were complex and numerous.Both temperate element and Mediterranean-Central-Asia element were the main part of local flora.The temperate element characteristics were the typical features of local flora.The particular components only include six Chinese endemic genera.Both xeromorphy and antiquity are domination in the flora classified as Old Mediterranean and East Asia element according to their origin.

In order to obtain the excellent phosphate-solubilizing bacteria resources in the rhizosphere soil of the alpine meadow,four phosphate-solubilizing bacteria were screened from the rhizosphere soil of an alpine meadow in Qinghai province and identified by 16S rRNA gene analysis. Through the anti-molybdenum antimony colorimetry and pot experiment the effects of dissolving phosphorus and promoting growth were studied. The results showed that the four strains were Pseudomonas. They all could form prominent phosphate solubilizing circles. When cultured in inorganic phosphate liquid medium for 7 days,the phosphorus the four strains released was 156.17~511.33 μg·mL ^-1. Various organic acids were secreted by the four strains during phosphate solubilization,and the total organic acid amount ranged from 522.36 to 986.69 mg·L ^-1. Pot experiments showed that four strains could significantly increase the plant height and aboveground dry weight of Elymus dahuricus,and promote the growth of Elymus dahuricus. Strains MXSC5,MXSC6 and MQC13 could increase the contents of total N and total P in plants,and the four strains also all had a positive effect on available N and available P content of soil. The results help to investigate further the role of phosphorus-solubilizing bacteria in the promotion of plant growth and the development and utilization of microbial fertilizers.

A study was conducted to learn the annual water content variation in the leaves and top branches of four Rhododendron Species in the alpine shrubland of the Qilian mountains of northwestern China.The study also probed the relationship between water content variations and other ecological factors,and the relationship between moisture change and the plant’s metabolism.Results show that:1.Water content of leaves and top branches of the four Rhododendron Species changed periodically-abundant in the plant growing stage, and scanty during its dormancy.In the plant growing period,the leaf transpiration rates rose with the lengthening of the newly springing out branches,which amounted to more than 99% of the total growing in a year.2.The water content of leaves and top branches was notably affected by the soil temperature,though not by the extent of soil saturation.3.Different degrees of leaf coiling synchronized with the variations of moisture content of leaf tissues.4.Variations of tissue water content of the four Rhododendron Species resulted from their acclimation to the severe alpine conditions.Still there existed differences among the four species in water content variation and adaptation strategy.

Hexi Corridor is located in the arid hungriness oasis region where soil salinization is very serious and results in the difficulties of turf establishment and gardening.In order to solve such problems,technologies of lifting turf bed and paving film at understratum in combination to soil replacement were adopted to establish turf.The results show that treatment of lifting turf bed and paving film at understratum without replacement soil led to good-quality turf establishment.The treatment of soil replacement without paving film at understratum maintained good turf quality at seedling periods,but turf quality declined gradually with the increased soil saline-alkali content from underground caused by the action of soil capillarity.The correlative analysis indicates that all turf quality indices had significantly negative correlation with soil saline content.Therefore,the technology of saline partition by paving understratum film in high saline-alkali lands should be broadly applied in agricultural activities in the arid hungriness oasis regions.

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.

In this experiment,a new line of Timothy ( Phleum pratense) (T) cultivated by Gansu Agricultural University was used as the test material,and the variety of Timothy ‘Sichuan’(CK1) and Timothy ‘Minshan’(CK2) were used as controls. The changes of physiological and biochemical indexes of the three materials under low temperature stress (0℃,-10℃,-20℃,-30℃),their cold resistance strength were studied in order to cultivate high-yield,high-quality,and stress-resistant timothy breeds. The results showed that low-temperature treatments had significant effects on the soluble sugar (SS),peroxidase (POD) and catalase (CAT) contents of the tested timothy ( P<0.05);but had no significant effect on malondialdehyde (MDA),superoxide dismutase (SOD),or chlorophyll (CHL) content. With the intensification of the stress,the SS content of the test materials showed a trend of first decreasing and then increasing,the content was the lowest at -20℃ (8.6 mg·g ^-1),and the POD activity showed a trend of first increasing and then decreasing,at -20℃ the activity was the highest (606.23 U·g ^-1·min ^-1),and the CAT activity increased under cold exposure. The SS content,SOD and POD of T was significantly higher than that of CK1 and CK2 ( P<0.05) under the treatments of -10℃ to -30℃. Overall,the new timothy strain (T) has strong cold resistance and is suitable for further regional and production trials.

To investigate the responses of alfalfa root morphological traits to phosphorus supply， a total of 31 plant materials were selected comprising 30 varieties of Medicago sativa L. and one variety of Medicago falcata L.， and three levels of phosphorus addition treatments were set up at P ₅ （5 mg·kg ^-1 KH ₂PO ₄）， P ₂₀ （20 mg·kg ^-1 KH ₂PO ₄）， and P ₅₀ （50 mg·kg ^-1 KH ₂PO ₄）. To screen low phosphorus tolerant alfalfa varieties with high phosphorus use efficiency， we measured the aboveground and belowground biomass and root morphological indices for the 31 alfalfa varieties. The results indicated that the aboveground and belowground biomass of alfalfa were lowest under P ₅ treatment. With increasing phosphorus supply， the aboveground biomass of alfalfa significantly increased， reaching its highest level under the P ₅₀ treatment. Under the P ₂₀ and P ₅₀ treatments， the root biomass of alfalfa was significantly higher than that under P ₅， but there was no significant difference between P ₂₀ and P ₅₀. However， the root morphology showed significant variation among different varieties. Among them， ‘HD’‘Algonguin’‘Magna Graze II’ and ‘Longmu 801’ had higher biomass than other varieties， and exhibited greater root morphological plasticity with higher root length， root volume， root surface area， and root diameter， which demonstrated tolerance to low phosphorus condition. The results provide a scientific basis for optimizing alfalfa cultivation and improving phosphorus fertilizer utilization efficiency.

WRKY proteins are one of the largest families of transcription factors （TFs） found in plants. Members of this family play important bidirectional regulatory roles in plant growth and development， biomass formation， secondary metabolite synthesis， and response to biotic or abiotic stresses. This paper provided a comprehensive review of the structural features and classification of WRKY TFs in plants， as well as their biological functions in plant growth and development， secondary metabolite synthesis， and biotic and abiotic stresses unearthed in the last five years， and also provided an outlook on the subsequent related studies of WRKY family members， aiming to provide technical references for further excavation of plant WRKY family members and their biological function studies.

Alfalfa （ Medicago sativa L.） is a globally important leguminous forage crop， widely cultivated and utilized due to its high biomass yield， nutritional value， strong adaptability， and excellent palatability. Flowering time is a critical stage in alfalfa growth cycle， directly affecting forage yield and quality. However， variations in environmental factors and genetic characteristics often lead to significant differences in flowering time， which in turn affecting its production， cultivation， management， and harvesting efficiency. In recent years， significant progresses have been made in the field of molecular biology， revealing the regulatory mechanisms of flowering gene expression was influenced by photoperiod， temperature and hormones. However， in China， the research on alfalfa flowering time regulation remains insufficient， with challenges including weak basic research， outdated breeding techniques， and inconsistent flowering periods among cultivars. This review summarizes the recent advances in the regulation of alfalfa flowering time， explores the ecological factors and genetic mechanisms influencing flowering， and proposes future optimization strategies for breeding and cultivation management. The aim is to provide theoretical support and practical guidance for high-yield， high-quality alfalfa breeding and sustainable utilization.

The anatomical structure of leaves in four species of ornamental grasses, Iris lactea.var. chinensis,Carex lanceolata, Pennisetum alopecuroides, Phalaris arundinacea var. picta,were studied by using paraffin sections and microscope technology,in order to provide anatomical foundation for their wide application in future. We observed the size and arrangement style of epidermis cells,veins and mesophyll cells in the leaves of these ornamental grasses. For I. Iris lactea. var. chinensis,the cuticle on the epidermal cells and the whole leaf were thicker,mesophyll cells were multilayered in neat arrangement,and the huge air cavity was intersected in the middle mesophyll. Sclerenchyma cells were attached to upper and lower epidermis,above or below parallel veins. And there was abundant tannin in the mesophyll cells. As for Carex lanceolata,the upper epidermal cells were 4~5 folds larger than the lower ones,and the layer number of mesophyll cells in the adaxial plane were bigger than that in the abaxial plane. The gas cavity between the mesophyll was developed,which was separated by leaf vein so as to form a huge gas chamber;Furthermore,the bulliform cells in the middle vein were large and numerous,so the leaf can fold and close into half when lacking water. The leaf structure of Pennisetum alopecuroides was similar to that of Miscanthus. It is a C ₄ plant,with large,medium and small veins arranged alternately,and pith cells were in the mid-vein. In Phalaris arundinacea var. picta there were large bulliform cells above the mid-vein,and small gas cavity among the mesophyll cells. Some mesophyll cells contained chloroplasts,and some having leucoplast,respectively,corresponding to the yellow-green or white-green stripes on the leaf surface. The leaf anatomical structures of the four ornamental grasses showed that Iris lactea.var. chinensis, Carex lanceolatax and Phalaris arundinacea var. picta could not only adapt to arid lands because of their structure traits,but also to wet lands with developed gas cavity; Iris lactea.var. chinensis are also resistance to cold; Pennisetum alopecuroides has strong adaptability to drought and tropical high temperature habitat.

To elucidate the responses of organic acids secreted by the roots of Thinopyrum ponticum under salt stress and their interactions with root traits and rhizosphere soil physicochemical properties， a controlled experiment with four salinity treatments was established： control， mild， moderate and severe salt stress （with soil salt contents of 0%， 0.2%， 0.4%， and 0.6% w/w， respectively）. Untargeted metabolomics was employed to analyze relative abundance variations and regulatory mechanisms of organic acids in root exudates. The results demonstrated that salt stress significantly decreased the secretion of organic acids including 1-hydroxy-2-naphthoic acid， succinic acid， homogentisic acid， phenylpyruvic acid and indolelactic acid （ P<0.05）， while significantly enhancing the secretion of phenoxyacetic acid （ P<0.05）. However， no significant effects on the secretion of 3-hydroxybutyric acid and shikimic acid. Principal coordinate analysis （PCoA） revealed significant differences in root-secreted organic acid profiles between control and salt-stressed treatments （mild， moderate and severe salinity） （ P<0.05）. Correlation analysis demonstrated that soil salinity， electrical conductivity， water content， and pH were key determinants influencing root organic acid secretion. Path analysis further revealed that salt stress promoted phenoxyacetic acid secretion through soil salinization-mediated suppression of root morphological traits. These findings provide a theoretical basis for the in-depth analysis of the physiological mechanisms of plant salt tolerance.

Based on an EST in the SSH library of Medicago sativa L., a full length of 1678 bp cDNA was isolated by RACE. The cDNA sequence was predicted to contain a 1281 bp ORF and code a protein of 426 amino acids, which is homology to Arabidopsis thaliana DEAD-box ATP-dependent RNA helicase 56(RH56) and RH15. The gene was predicted to be a DExD/H box RNA helicase gene and named as MsRH (GenBank accession No. JX508648). Transient expression of MsRH-GFP fusion in onion epidermis cell indicated that the MsRH localized in nucleus. To investigate the function of MsRH, the plant over-expression vector pBI- MsRH was constructed and transferred into tobacco by Agrobacterium LBA4404. After PCR and RT-PCR analysis of five kanamycin resistant plants, 35S:: MsRH was confirmed to insert into tobacco genome and transcribe mRNA successfully. After treated with 250 mM NaCl for seven days, the proline contents of transgenic plants were lower than those of control plants (WT), and the malondialdehyde contents and relative electric conductivity were higher than those of control tobacco (WT). Taken together, these results demonstrated that MsRH increased the salt sensitivity of tobacco plants under salt stress.

NAC transcription factors are specific to plants and play an important role in a diverse set of developmental processes. Using RT-PCR and RACE technology with a pair of degenerate primer designed base on the sequence of the homologous gene from other plants, a cDNA of NAC gene was cloned from Bothriochloa ischaemum, named BiNAC. Sequence analysis showed that the full-length of cDNA sequence was 1549 bp including an 1125 bp open reading frame which encoded a 374-amino-acid polypeptide and had the typical characteristics of NAC family. Phylogenetic tree analysis indicated that NAC gene belonged to the ATAF subfamily, and the BiNAC gene of B. ischaemum was closely related to that of Sorghum bicolor with 94% homology. Real-time PCR results revealed that the expression of BiNAC was the most abundant in stem and the least in root. The expression level of BiNAC gene was increased in leaves with NaCl stress. Meanwhile, the plant expression plasmid pBI121- BiNAC-GUS was constructed successfully, which will lay a foundation for the functional analysis of BiNAC gene in the future.

The study of plant population density and spatial distribution can reflect the ecological phenomena and laws of plant communities in the process of grazing. To study the density differences and spatial distribution changes of Cleistogenes songorica populations in desert steppe under different grazing intensities,a randomized block trial design was adopted:contral area (CK),light grazing area (LG),moderate grazing area (MG),and heavy grazing area (HG). Data were collected by mechanical sampling methods and analyzed in combination with geostatistical methods. The results showed that the density of C. songorica in desert grassland was LG>HG>CK>MG,with the increase of grazing intensity,the density of C. songorica increased first and then decreased,but under the condition of heavy grazing,the density increased again. The absolute density proportion of C. songorica in the community gradually increased with the increase in grazing intensity,the proportion of absolute density of C. songorica in the community is HG>MG>CK>LG. Under the four treatment areas,the values of D ₀of typing dimension were relatively similar,and the structural ratios C/(C ₀+C) of CK,LG,and MG were larger than 0.75,the spatial structure ratio C/(C ₀+C) of HG is 0.100. Under grazing conditions,the spatial distribution of C. songorica species was relatively uniform,the spatial heterogeneity was weakened,and the spatial distribution was mainly affected by structural factors.