Grazing is one of the most important uses of grassland ecosystems,and different grassland types,grazing intensities,herbivore assemblages,grassland use types and climate change all influence the structure and function of grassland ecosystems. It is very important to understand the mechanisms of grazing and climate change on grassland ecosystems for their sustainable development. In order to provide a theoretical reference for the adaptive management and sustainable development of grassland ecosystems,this paper provided a systematic review of the mechanisms by which grazing affects the structure and function of grassland ecosystems,and provided an outlook on several important research directions in this theme,and future research issues as the following:(1) to improve spatial coupling analysis in grazing grassland ecosystems;(2) to focus on multifunctionality studies of grassland ecosystems;(3) to elaborate the multi-factorial nested experiments on grasslands in the context of global change;(4) to refine the mixed grazing experiments with different herbivore assemblages;(5) to standardize the methods of grassland ecological experiments.

In recent years,due to the continuous development of urban industry and the excessive use of chemical fertilizers,the lack of mineral elements and pollution in soil have seriously affected the sustainable development of agriculture. As a natural biological bacterial fertilizer,arbuscular mycorrhizal fungi (AMF) is able to effectively promote the absorption of mineral elements and improve growth conditions around plants. At the same time,in heavy metal contaminated soils,AMF can reduce the toxicity of heavy metal to plants and enhance the adaptability of plants to environmental changes. Up to now,great progress has been made in the researches on the physiological and molecular mechanism of AMF regulating the absorption of mineral elements by plants. A large number of mycorrhizal-induced genes have been identified,but a systematic and comprehensive summary is still lacking. Based on this,this paper summarized the relevant studies on AMF regulating the absorption of mineral elements in plants at home and abroad,and reviewed literature on the physiological and molecular mechanisms of AMF affecting the uptake of macroelements and trace elements by plants,and the mechanism of AMF alleviating the heavy metal toxicity to plant. According to the challenges and deficiencies of existing researches,the outlook is put forward,which aims to provide a certain scientific basis for the in-depth understanding of the mechanism of AMF affecting the absorption of mineral elements by plants and the agricultural application of biological bacterial fertilizer.

In order to investigate whether artificial grassland can be established in Nagqu area and what kind of forage species is suitable for planting,this experiment selected the cold and drought-resistant forage species to carry out an introduction and screening test artificial grassland in the area. Through the comparison and evaluation of the harvested forage yield with the yield of natural grassland in Nagqu and other artificial grassland in the four major grassland areas in China,it can be seen that the yield of the harvested forage in the experiment is exponentially higher than that of the natural grassland in Nagqu,and the average yield of the artificial grassland in the experimental area is not lower than that of the artificial grasslands in the other grassland areas in China,which indicate that high yielding artificial grassland can be established in Nagqu region under adequate water and fertiliser management conditions. At the same time,the screening of suitable pasture species was carried out based on the seedling emergence and growth of different pasture species in the year of sowing and the seedling emergence of perennial pasture species in the following year (i.e. overwintering ability). The results showed that Avena sativa, Triticum secale, Brassica rapa and Brassica napus were suitable for planting in the Nagqu area. Elymus sibiricus and Elymus nutans,which were able to overwinter successfully,can be used as screening species for perennial grassland,but their stability in the second and subsequent years after overwintering remains to be studied.

Melatonin is a small molecule indolamine hormone that widely exists in plants,and the studies have already clarified its synthetic pathway,catabolism and physiological functions. Melatonin can act as a signaling molecule to regulate plant circadian rhythms,seed germination,root and flower development,and also help to enhance the resistance of plants to various stresses. In this paper,the physiological functions of melatonin in regulating growth and development of herbaceous plants were summarized up,and its regulatory effects in response to abiotic and biotic stresses were particularly focused on. Additionally,functional study on melatonin in growth,development and stress resistance,as well as its application in stress resistance breeding in forage species were prospected. This review is expected to provide insight into improving the stress resistance,yield and quality enhancement of forage plants by using melatonin.

Glycerol-3-phosphate acyltransferase (GPAT) is the rate-limiting enzyme of glycerol biosynthesis,participates in the biosynthetic pathway of various lipids,and plays important roles in plant growth and stress resistance. To understand the role of GPAT genes in the response of alfalfa ( Medicago sativa) to abiotic stress,a total of 73 MsGPATs genes in alfalfa were identified using bioinformatics methods in this study. Studies showed that the MsGPATs gene were unevenly distributed on chromosomes,and most genes exhibited segmental duplication. Phylogenetic tree analysis was classified into three subgroups. Gene structure and protein conservative motif analysis showed that most of the MsGPATs gene family members contained 2~3 exons or 11~12 exons,and at least one conserved motif. Promoter cis-acting elements analysis showed that different MsGPATs genes contained different light,auxin and stress response elements. Gene expression profiling analysis showed that a total of 10,5 and 18 MsGPATs genes actively responded to high salt,high alkali and mixed saline-alkali stress,respectively,which could be used as candidate genes for further research on saline and alkali tolerance in alfalfa.

Taking 1 329 core journal articles on the researches on saline-alkali soil improvement with plants from 2000 to 2022 retrieved in CNKI and Web of Science (WOS) databases as the data source,the data visualization software was used to qualitatively and quantitatively analyze the clustering,hot spots,co-occurrence,semantic network and other presence,and the current situation of plant improvement saline-alkali land at home and abroad was clarified from the perspectives of research trends,research hotspots and improvement effects of plant improvement saline-alkali land. The results show that the number of literature on saline-alkali land research is increasing year by year,and the effect of plants on improving saline-alkali land is a hot research problem. Herbaceous plants are the most commonly used plants in saline-alkali land improvement,and there are mainly 15 species of shrubs and trees. Planting plants can mainly reduce soil pH,salt content and salt ion concentration in saline-alkali land,improve soil physical characteristics,and increase soil fertility level. The improvement effect of different plants on saline-alkali land is different,and the establishment of saline-alkali plant bank as the basis for improving saline-alkali land is the focus of future research in this field,and the progress of saline-alkali land improvement is reviewed based on existing research,which has guiding significance for the subsequent ecological restoration and sustainable development of saline-alkali land.

Inner Mongolia grassland is an important livestock production base and northern ecological security barrier in China,and its economic development and ecological protection issues are the hot topics of research nowadays. Family ranch as a major typical form of livestock production organization has become an important element in the development of agriculture and animal husbandry in Inner Mongolia. In recent years,climate change and human disturbance have caused the degradation of grasslands. This not only brings about problems such as the decline of ecosystem function,but also has an important impact on the economic development of family ranches. This paper discussed the development and definition of family ranch,provided an overview of the roles produced and the impacts caused from the management strategies of family ranch under different grassland types in Inner Mongolia,and finally raised questions and outlooks on the business model,herders' business awareness,management system,financial system and social service system,and landscape remote sensing technology applications relevant to the family ranch in Inner Mongolia. It is expected to provide a scientific reference for achieving grass-livestock balance at the scale of farmer's household in Inner Mongolia,while improving the economic efficiency of farmers and herders.

Grass seeds are the foundation of lawn industry,but we lack our own turfgrass varieties and the turfgrass seeds used in practice mainly rely on importation from abroad. Therefore,turfgrass breeding needs to be strengthened urgently. The conventional breeding cost a long period of time,low efficiency and is difficult to achieve precise targeted breeding. However,modern biotechnologies provide a new and effective way for turfgrass breeding,in which the key is a construction of an efficient regeneration system for turfgrass to accelerate the propagation speed,and be carried out its genetic transformation with regeneration system. This review mainly summarized the researches on the regeneration systems of some cold season and warm season turfgrasses in recent years,and focused on the key factors and existing problems affecting the regeneration process,and prospected the future development of turfgrass regeneration,with a view to provide a reference for the research,development,promotion,and application of new turfgrass varieties in the coming days.

As one of the important industries in the field of agriculture,the grass seed industry is playing an increasingly important role in improving the efficiency of farming,increasing the income of farmers and herdsmen,and promoting high-quality economic and social development. The collection,preservation,identification,evaluation and innovative utilization of germplasm resources and the breeding of new varieties (lines) have become hot topics in the current research of grass seed industry. This paper mainly summarized and prospected the genetic diversity of grass germplasm resources from four aspects:morphology,biochemistry,cytology and molecular level,aiming to provide reference for the creation and breeding utilization of grass germplasm resources.

In order to reveal the mechanism of arbuscular mycorrhizal fungi and plant symbiosis in restoring sandy degraded land in the northern farming-pastoral ecotone,this study selected three common grass species: Medicago satuva L., Bromus inermis Leyss and Festuca arundinacea Schreb as test materials in the degraded land, and the inoculation with Glomus etunicatum (GE),Glomus mosseae (GM),Glomus intradicular Glomus (GI) to those species and non-inoculated (CK) treatments were set up. The infection rate of endoroot balloon (GI) to Medicago satuva, Bromus inermis and Festuca arundinacea was the highest,followed by balloon Moses (GM),and the infection rate of balloon (GE) was the lowest. The biomass of alfalfa and fescue inoculated with GM and GI was significantly higher than that of inoculated with GE. Correlation analysis also showed that AMF infection rate was positively correlated with plant height,biomass and the number of tillers (or branches). In conclusion,the plant height,biomass and the number of tillers (or branches) of the three grassland plants were promoted by AMF inoculation. The combination of GI inoculation to Bromus inermis is suitable for the degraded land in the farming-pastoral ecotone,which provides a method of efficient vegetation restoration of the degraded land by microorganisms.

Informatization is a key measure to promote the high-quality development of grassland undertakings in the new era and realize the modernization of the governance system and governance capacity in pastoral areas. Grassland conservation and the modernization of pastoral areas in China urgently require information technology support. In this study,the needs of the informationization construction in the pastoral areas in China,the applications of cutting-edge information technologies in the fields of grassland conservation and animal husbandry production and herdsman’s living improvements in Chinese pastoral areas,and the current status of grassland informationization construction in China were analyzed and summarized. The challenges which the grassland informationization construction in China are facing was identified. Meanwhile,taking the needs for the informationization on grassland conservation and the practices and managements of the productions in pastoral arear as a root in this research,the mode of informationaization in pastoral area in China was studied by taking into an account of the current infrastructure and scientific and technological development level in the pastoral areas,and by a following of the basic technical framework of informationization construction for the government. Starting from the construction of management display platform for government,the construction of applications integration,big data construction,the construction of infrastructure,and the construction of standard specification system and security and comprehensive social governance,a constructive system and framework for the informationization construction in grassland areas was proposed to provide a theoretical guidance and policy suggestions for informationization construction in pastoral areas,for a purpose of promoting the formulation of top-level designs for pastoral informationization construction and enhancing the efficiency of grassland informationization construction.

Plant-endophyte symbioses play an important role in alleviating abiotic and biotic stresses to plants. Under drought and salt stresses, endophytic bacteria can enhance the resistance of plant to the stresses by regulating plant photosynthesis, concentration of hormones, content of osmoregulatory substances, activity of antioxidant enzyme, and expression of genes to ensure a normal growth and development of plant. In recent years, plant growth-promoting bacteria (PGPB) inoculants have also been widely studied and applied. In this paper, we reviewed the diversity of endophytic bacteria, the regulation of plant genes by plant symbiotic endophytes and PGPB under drought and salt stresses, and provided a reference for the in-depth study of the molecular mechanism of endophytic bacteria to improve the tolerance of plant to drought and salt stresses.

Grasslands are important natural resource and ecological barrier in our country. Grassland ecological restoration is an important part of China's ecological conservation, as well as an important approach to enhance the ecosystem service function and carbon sequestration potential of grassland. Extensive studies have been conducted on degraded grassland, and many effective restoration practices have been proposed. However, there is a lack of comprehensive and target-oriented summaries of these restoration practices. This study conducted a systematic review of domestic and international research on grassland ecological restoration based on bibliometric research approach. We summarized the three stages of grassland ecological restoration in China and explored a regional-classified-hierarchical ecological restoration model for grasslands under different regions, different degradation types and different degradation degrees. Additionally, we provided relevant suggestions for the future development of grassland ecological restoration in China, and aimed to provide scientific basis for the ecological restoration and sustainable management of grasslands in our country.

In order to reveal the impacts of future climate change on grassland ecosystems and their responses,this study assessed the spatiotemporal dynamics of global grassland ecosystems and their net primary productivity (NPP) in 2020-2100 based on four future climate scenarios (including SSP126,SSP245,SSP370,and SSP585) using an improved comprehensive sequential classification system (CSCS) and a segmentation model. Results showed that the global mean annual temperature (MAT) and mean annual precipitation (MAP) would exhibit an overall upward trend in all four climate scenarios. In the SSP126 and SSP245 scenarios,the global grassland area was expected to decrease by 1.94 million km ² and 1.78 million km ² by 2090 s,respectively,mainly due to the reduction of tundra and alpine steppe. In contrast,the global grassland area was expected to increase by 0.68 and 1.37 million km ² by 2090 s in the SSP370 and SSP585 scenarios,respectively,which was mainly caused by the increase in the area of the tropical savanna. Global grassland NPP showed an increasing trend in SSP126,SSP245,SSP370,and SSP585 scenarios,expecting to increase by 0.25,1.96,5.78,and 7.52 Pg DW by 2090 s,respectively. Tropical savanna would contribute the most. In the context of global warming and humidification,tropical savanna and tundra and alpine steppe grasslands would be more vulnerable to future climate change.

Lodging is one of the important factors affecting the yield and quality of oat. It is a prominent problem to be solved urgently in the breeding and production of oat. Strengthening the systematic research on the physiological and molecular mechanisms of oat lodging resistance is of great significance for promoting the germplasm innovation of oat lodging resistance and cultivation with high yield and high efficiency. Based on that objective,the study on lodging of oats is summarized systematically up in this paper,the influencing factors of lodging occurrence and the status quo of lodging resistance evaluation of oat were combed,the research progress in the morphology,physiology and anatomy of lodging resistance of oat was reviewed,the relationship of plant morphology,physical and chemical substances and cultivation measures with the lodging of oat was summarized up as well. In this paper,we prospected the researches on the characteristics of stem mechanics,endogenous material synthesis,genome wide association study (GWAS) of lodging resistance traits and quantitative trait locus (QTL) mapping.,functional gene mining and molecular mechanism analysis of oat,in order to provide references for the genetic improvement and breeding of the inverted resistance varieties of oat,and promote the development of researches on stress resistance of oat.

Leaf chlorophyll is a critical substance for plant photosynthesis,while nitrogen is an important component of chlorophyll. Therefore,soil nitrogen may be an important factor to affect leaf chlorophyll content. However,little attention has been paid to whether leaf chlorophyll content exhibits a nonlinear response to a soil nitrogen gradient and the possible mechanisms behind it. In this study,dominant plants in alpine meadows on the Qinghai-Tibet Plateau were used as the research object,and an eight-year nitrogen addition gradient experiment was conducted with nitrogen addition levels of 0,2,4,8,16,and 32 g·m ^-2·a ^-1. We found that leaf chlorophyll content showed a first increasing and then decreasing pattern in response to nitrogen addition gradient,and the peak value mostly appeared at 8 g·m ^-2·a ^-1. At low nitrogen levels,leaf chlorophyll content was positively correlated with soil inorganic nitrogen but negatively with soil pH and plant height. At high nitrogen levels,leaf chlorophyll was not correlated with soil inorganic nitrogen or pH,but exhibited a nonlinear relationship with plant height. In addition,we found that regardless of low or high nitrogen additions,there was a parabolic relationship between leaf chlorophyll content and specific leaf area. This study demonstrated that the leaf chlorophyll of alpine plants exhibited a threshold in response to nitrogen additions gradient,and the underlying mechanisms below or above that threshold are different. Overall,this study suggests that in the context of nitrogen enrichment,the relationship between alpine plant chlorophyll and soil nitrogen availability is complex,which may further affect carbon sequestration in alpine grassland ecosystems.

Flowering is a turning point for plants from vegetative growth to reproductive growth. The yield and quality of alfalfa ( Medicago sativa L.) are closely relevant to its flowering time. Photoperiod is one of the important factors affecting plant flowering. The CONSTANS-like ( COL) gene family plays an important role in the regulation of photoperiod flowering. In order to reveal the function of COL family genes in alfalfa flowering regulation, MsCOL2 gene was cloned from alfalfa in this study. This gene encodes for 401 amino acids. Tissue differential expression analysis showed that MsCOL2 had the highest expression in flowers. Expression analysis at different developmental stages of flowering showed that MsCOL2 had the highest expression level at flower bud differentiation stage;under different photoperiod conditions,the expression level of MsCOL2 had different rhythmic expressions;After treatment with exogenous hormones 50 μmol·L ^-1 Gibberellin 3 (GA3) and 100 μmol·L ^-1Salicylic acid (SA),the expression level of MsCOL2 showed different trends. In order to verify the effect of overexpression of MsCOL2 on the expression of flowering-related genes,the expression levels of flowering-related genes under overexpression MsCOL2 lines were analyzed. The results showed that the expression level of the genes promoting flowering was down-regulated and the expression level of the genes inhibiting flowering was up-regulated. Flowering phenotype analysis showed that overexpression of MsCOL2 delayed flowering,indicating that MsCOL2 plays an important role in regulating of delayed flowering.

Epichloë grass endophyte is a group of fungi that finish most their life cycle in the intercellular space of the host grasses,but do not cause obvious external symptoms on the hosts. As an important agricultural microbial resource,it can promote the growth of hosts and improve the host's resistance to adversity. In addition, some alkaloids produced by the symbionts formed by some endophytic fungi and their host,can cause herbivorous livestock be poisoned and affect the healthy development of grassland animal husbandry. This dual characteristic of grass endophyte has become a research hotspot in the field of international grass industry for the past 30 years. In this study,the nomenclature history,classification status of teleomorph and anamorph grass endophyte,classification methods and significance of grass Epichloë endophyte were reviewed. Moreover,the resources and the distribution of grass endophytic fungi found in China and the research progress about grass endophytic fungi in stress resistance breeding were also summarized. The review was prospected to provide scientific basis for mining and utilizing beneficial grass endophytic fungi resources,cultivating new varieties of excellent plants,developing modern grassland animal husbandry and taking the ecological environment construction.

The party and the state pay a great attention to the Ecological Civilization Construction. It is an important part of the Ecological Civilization Construction in the new era to accelerate the construction of natural protected areas system with national parks as its major composed part. Promoting the construction of grassland natural parks is an important supplement to the construction of natural protected areas system in the new era. This paper reviewed,sorted out and summarized the construction processes of China's natural protected areas system and the developmental processes of grassland natural parks in the new era. The future development of grassland natural parks were carefully considered,and the macro development strategies and detailed suggestions on ecological protection,planning,feature mining and achievement sharing were proposed to provide reference for understanding and supporting the construction of grassland natural parks and the high-quality development of grassland cause in China.

In order to accurately evaluate the stability and adaptability of major domestic and foreign forage oat varieties in different areas of Sichuan and the representativeness and differentiation ability of the different testing sites,the bipolt and BLUP prediction model were used to jointly analyze the yield data of 12 oat cultivars tested in five testing eco-geographical sites in 2018. The results showed that cultivar 'Sun God' and 'Charm' had a fecundity and stable yield with a high potential to be planted in a large scale in Sichuan Province. The cultivar 'shooter' achieved a high yield in Hong Yuan,Aba,and can be extensively planted in high altitude areas with similar ecological conditions. Hongya county of Meishan city has good representativeness and distinguishing power,and is an ideal place for testing trial and promotion showing of oat varieties. In this study,we objectively evaluated the adaptability of oat varieties and the representativeness and differentiation capability of the candidate sites,our results can provide a basis for the selection of the excellent oat varieties and/or testing sites for the production of high-quality oat forage in Sichuan Province.