Leymus species have considerable economic and ecological value, but information on their genome size and genomic characteristics remains limited, constraining molecular research in this genus. Using L.secalinus as a representative species, flow cytometry was used to evaluate the effects of three lysis buffers (LB01, Tris-MgCl₂, and Galbraith's), two leaf materials (fresh young and mature leaves), and two reference standards (Zangqing 320 barley and Chinese Spring wheat) on genome size estimation. The aim was to establish a suitable flow cytometry protocol for Leymus species. The results showed that LB01 was the most suitable buffer for preparing nuclear suspensions. Fresh young leaves were more suitable than mature leaves, and Zangqing 320 barley was the preferred reference standard. Genome sizes of six Leymus species (L. secalinus,L. tianschanicus,L. multicaulis,L. cinereus,L. mollis, and L. racemosus) were subsequently estimated using internal and external standard methods. The estimates ranged from 9.16 to 15.56 Gb with the internal standard method and from 9.76 to 14.33 Gb with the external standard method, with some differences between the two approaches. The optimized protocol provides a methodological basis for phylogenetic studies, ploidy breeding, and the utilization of genetic resources in Leymus.
Alfalfa (Medicago sativa) is an important forage legume whose growth is frequently constrained by abiotic stresses such as drought, salinity, alkalinity, and temperature extremes. Fatty acyl-CoA reductases (FARs) play key roles in cuticular wax biosynthesis and stress responses, but the FAR gene family in alfalfa remains poorly characterized. Ten MsFAR genes were identified from the alfalfa genome. Bioinformatic analysis showed that the encoded proteins contained 431-868 amino acids, with predicted molecular weights of 48 906.12-99 225.37 Da and theoretical isoelectric points of 7.06-8.97. Phylogenetic analysis classified the MsFAR genes into three subfamilies, with members showing similar conserved motifs. Promoter analysis revealed abundant cis-regulatory elements associated with abiotic stress and hormone responses. RT-qPCR analysis showed that most MsFAR genes were transiently upregulated under drought stress, with MsFAR7 showing a particularly strong induction. Under salt stress, family members reached peak expression at different time points. Under heat stress, most genes peaked at 12 h, whereas MsFAR8 maintained relatively high expression from 8 to 24 h. Under cold stress, MsFAR4 and MsFAR8 were generally repressed, while several other genes were upregulated at specific time points. MsFAR7 and MsFAR9 showed transcriptional responses to multiple stresses and are therefore promising candidates for further functional studies.
This study investigated the growth-promoting effects of three endophytic fungi-Trichoderma rossicum strain MDK, Colletotrichum sp. strain MEK, and Floccularia luteovirens strain MF-on Medicago sativa through a field experiment involving seed soaking. A comprehensive set of indicators was measured, including growth characteristics, physiological and biochemical parameters, as well as soil physical and chemical properties. Furthermore, high-throughput sequencing was employed to assess the influence of seed treatment with endophytic fungi on the composition of root endophytic fungal communities in M. sativa. The results demonstrated that all three endophytic fungi promoted the growth of M. sativa. Specifically, the MDK treatment increased plant height and root length by 32.84% and 40.24%, respectively, compared with the control. The MEK treatment yielded the highest fresh and dry weight of alfalfa, with increases of 175.25% and 193.51%, respectively, relative to the control. Endophytic fungal seed soaking also significantly affected the physiological parameters of M. sativa (P<0.05). In the MEK, MDK, and MF groups, peroxidase (POD) activity increased by 12.50%, 11.11%, and 8.33%, respectively, while vitamin C (Vc) content increased by 41.38%, 47.39%, and 68.96%, respectively, compared with the MCK group. Meanwhile, proline (Pro) content decreased by 22.14%, 43.66%, and 48.45%, and malondialdehyde (MDA) content decreased by 8.45%, 39.33%, and 41.54%, respectively compared with the MCK group. The MEK treatment significantly increased soil total nitrogen, total phosphorus, and organic carbon contents (P<0.05). Illumina high-throughput sequencing revealed that endophytic fungal seed soaking markedly increased the Shannon index, Pielou index, and the number of unique OTUs of root endophytic fungi, and altered the community structure of root endophytic fungi in M. sativa. Notably, the proportion of Gibberella in M. sativa roots following MDK seed soaking was relatively high (29.43%). In conclusion, seed soaking with endophytic fungi promotes the growth of M. sativa, enhances stress resistance, improves the rhizosphere soil environment, and modulates the structure of root endophytic fungal communities. These findings provide a theoretical foundation and technical reference for the high-quality cultivation of M. sativa, and offer potential fungal resources for the development of plant growth-promoting agents.
To determine the physiological effects of exogenous melatonin on pansy (Viola tricolor) seedlings under drought stress and identify the optimal concentration for alleviating drought injury, normal water supply control was set up, followed by drought stress (soil field capacity 40%-45%) treatment and foliar spraying of melatonin at concentrations of 50, 100, 150, 200, and 250 μmol/L before drought stress. Plant height, osmolyte contents, antioxidant enzyme activities, chlorophyll content, and malondialdehyde (MDA) content were measured. The results showed that drought stress significantly reduced plant height, osmolyte contents, antioxidant enzyme activities, and chlorophyll content in stems and leaves, while increasing MDA content. Exogenous melatonin effectively alleviated these effects. As melatonin concentration increased, plant height, osmolyte contents, antioxidant enzyme activities, and chlorophyll content first increased and then decreased, whereas MDA content showed the opposite pattern. Compared with drought stress alone, 150 μmol/L melatonin increased plant height by 18.94% and reduced MDA content in leaves and stems by 81.47% and 57.73%, respectively. Superoxide dismutase, peroxidase, and catalase activities in leaves and stems increased by 71. 66% and 41. 67%, 59. 26% and 56. 00%,and 20. 86% and 18. 51%, respectively. Total chlorophyll, soluble sugar, soluble protein, and proline contents in leaves and stems increased by 43.43% and 39.17%, 71.19% and 70.78%, 79.40% and 56.43%, and 80.90% and 63.38%, respectively. Membership function analysis identified 150 μmol/L melatonin as the most effective treatment for alleviating drought injury. These findings provide guidance for the application of melatonin in drought-resistant cultivation of pansy and other ornamental plants under water-limited conditions.
To determine the optimal planting density for silage maize in southeast Gansu Province, this study focused on the cultivar 'Tieyan 53' and established five planting-density treatments: D6, 60 000 plants/hm2; D6.75, 67 500 plants/hm2; D7.50, 75 000 plants/hm2; D8.25, 82 500 plants/hm2; and D9.00, 90 000 plants/hm2. Agronomic traits, yield, forage quality, and phyllosphere microorganisms of silage maize were measured and analyzed across treatments. The results showed that planting density had significant effects on dry matter yield and crude protein content of silage maize. As planting density increased, dry matter yield also increased, reaching the highest value under the D9 treatment at 40 804.50 kg/hm2. Crude protein content was highest under the D7.50 treatment. Planting density had no significant effect on neutral detergent fiber or acid detergent fiber content. The highest relative feed value was observed under the D6 treatment, reaching 127.69. Differences in the α-diversity of phyllosphere bacterial and fungal communities were observed among the planting-density treatments. The bacterial Chao1 index was highest under the D9 treatment. Genera potentially associated with silage fermentation, including Lactobacillus, Weissella, and Bacillus, were detected under this planting density. The structure of the phyllosphere bacterial community was significantly correlated with forage-quality indicators, particularly fiber fractions (P<0.05). In contrast, the correlations between the phyllosphere fungal community and these indicators were generally not significant. Taking into account yield, forage quality, and the potential effects of phyllosphere microorganisms on silage fermentation, a planting density of 90 000 plants/hm2 is recommended for the cultivation of 'Tieyan 53' silage maize in southeast Gansu Province.
Solanum rostratum is a major invasive alien plant in natural grasslands of northern China. Its strong ecological adaptability and reproductive capacity pose a potential threat to native plant community structure and ecosystem stability. To evaluate its ecological effects, field plots were classified as uninvaded or subject to light, moderate, or severe S. rostratum invasion. Quadrat surveys were used to assess species composition, community characteristics, plant community diversity, and community stability. The results showed that S. rostratum invasion significantly altered the community structure and composition of native plants, reduced the important values of dominant native species such as Cleistogenes squarrosa, and led to the disappearance of key native species including Leymus chinensis, Echinochloa crus-galli, and Stipa capillata. Compared with the uninvaded plots, severe invasion by S. rostratum significantly reduced the Shannon-Wiener index, Simpson index and Margalef index of plant communities, while no significant effect was found on the Pielou index. Community stability initially increased and then declined as invasion severity increased, reaching its highest value under light invasion (1.27) and its lowest under severe invasion (0.85). Regression analysis showed that community stability was significantly and positively correlated with the Shannon-Wiener index, Simpson index, and Pielou index. These findings provide a scientific basis for targeted control of S. rostratum and the protection and restoration of natural grassland ecosystems.
Traditional monthly- and seasonal-scale drought indices fail to adequately capture short-term grassland drought processes, and thus cannot accurately characterize the differential impacts of drought during critical growth stages on forage yield. Based on daily meteorological data and monthly aboveground biomass data of natural pasture from 1991 to 2024, this study utilized the daily Meteorological Drought Composite Index (MCI), combined with various mathematical-statistical and machine learning models, to systematically analyze the spatiotemporal evolution of growing-season drought. In addition, models for assessing forage yield reduction rates in natural pasture were constructed, and the regional applicability of the different models was compared. The results indicate that the daily-scale MCI can accurately identify short-term flash droughts and extreme drought events while fully characterizing the onset and cessation of drought processes, making it highly suitable for dynamic monitoring of drought in the Hulun Buir grassland. In the study area, growing-season drought during the study period exhibited an overall fluctuating trend toward alleviation, characterized by a decrease in drought frequency but a slight increase in the risk of extreme drought. Spatially, drought exhibited a special pattern of 'more severe in the west and milder in the east', primarily occurring from May to August, with a high frequency of extreme drought events in July. Drought during the critical growth period from July to August emerged as a key factor constraining forage yield formation. The typical steppe exhibited higher drought sensitivity than the meadow steppe, whereas drought in the preceding autumn exerted a negligible impact on forage yield in the current year. Forage yield reduction in the typical steppe was predominantly driven by drought factors in August, and severe/extreme drought days from April to August, displaying significant nonlinear response characteristics, with the random forest regression model providing superior modeling performance. In contrast, yield reduction in the meadow steppe was regulated by the cumulative effects of severe and moderate droughts from April to August, exhibiting a primarily linear response that was best fitted by linear regression models.
This study investigated a photovoltaic (PV) park in desert grasslands on the northern slope of the Tianshan Mountains, focusing on the PV-induced spatial heterogeneity of plant-soil-microbial communities and the coupled responses of aboveground and belowground biological components to microhabitat differentiation, using field surveys, sampling, and high-throughput sequencing of soil microbial communities. The results showed that: (1) soil pH in the PV park was 8.14 ± 0.17, indicating further enhanced alkalinity relative to control (adjacent desert grassland). Soil organic matter (6.21±2.14 g/kg) and total nitrogen (0.45±0.10 g/kg) were 23.99% and 21.05% lower than those in the control, respectively, whereas total potassium (25.03±1.87 g/kg) and total phosphorus (0.85±0.11 g/kg) increased by 6.97% and 1.19%, respectively. (2) Within the PV park, inter-panel vegetation was dominated by Petrosimonia sibirica, Alhagi sparsifolia, Kalidium foliatum, Halocnemum strobilaceum, and Anabasis elatior. Although Anabasis elatior was absent from the control, a few Phragmites australis individuals occurred in scattered patches. The herb Petrosimonia sibirica exhibited pronounced growth enhancement in the park; its coverage (33.00%±15.64%) and fresh weight (137.50±109.58 g) were 53.49% and 14.58% higher than those in the control, respectively. At the micro-scale, Petrosimonia sibirica showed patchy distribution and marked spatial differentiation: growth (height, coverage, and fresh weight) in front-eave and under-panel microhabitats was greater than in rear-eave and inter-panel microhabitats. (3) At the phylum level, PV array disturbance significantly increased the relative abundances of dominant bacterial (Pseudomonadota, Bacteroidota, and Planctomycetota) and fungal (Basidiomycota, Chlorophyta, and Chytridiomycota). Soil pH and total potassium were key drivers of dominant bacterial abundance, whereas dominant fungal abundance was jointly governed by total potassium, total nitrogen, and organic matter. Bacterial communities were centered on carbon-cycling pathways; after PV operation, functional guilds involved in autotrophic carbon metabolism (e.g., phototrophs, photoautotrophs, aerobic photoautotrophs, and photosynthetic cyanobacteria) were significantly enriched. Fungal communities were dominated by saprotrophic and composite functional types, with enrichment of wood saprotrophs and plant pathogen-saprotrophs. These findings provide scientific support for achieving the "dual carbon" goals and for the high-quality development of renewable energy bases in sandy, gobi, and desert regions.
Vegetation restoration is a critical approach to rehabilitating degraded ecosystems, as it improves soil physicochemical properties and reshapes microbial community structures. However, the changes in soil properties during different restoration stages and their driving mechanisms on microbial communities remain unclear. In this study, we selected non-restored barren land and oat (Avena sativa) restoration fields with restoration histories of 1, 3, and 10 years in the Shigatse area of Xizang. Soil physicochemical properties, enzyme activities, and microbial biomass were measured, and high-throughput sequencing of 16S rRNA and ITS amplicons was performed to characterize soil properties and microbial communities across vegetation restoration and their interrelationships. The results showed that: (1) With increasing restoration years, soil physicochemical properties improved significantly. Total carbon (TC), total nitrogen (TN), dissolved organic carbon (DOC), dissolved total nitrogen (DTN), and ammonium nitrogen contents increased gradually, and microbial biomass carbon, nitrogen, and phosphorus increased significantly, with the most pronounced improvement observed after 10 years (P<0.05). Except for leucine aminopeptidase, soil enzyme activities increased significantly with restoration years (P<0.05), and were positively correlated with TC and DOC. (2) Vegetation restoration significantly increased the Chao1 indices of bacteria and fungi, and community composition differed significantly between restored and unrestored soils. Functional prediction indicated that bacterial functions related to carbon degradation and nitrogen fixation were enhanced in restored soils. (3) Mantel test revealed that TC, TN, and DOC were the key factors driving changes in bacterial and fungal community structures. In conclusion, vegetation restoration enhances soil nutrients and enzyme activities, facilitates the reconstruction of microbial community structure and functions, and promotes soil carbon and nitrogen cycling. The effects were most significant after 10 years of restoration, suggesting that medium- and long-term restoration has advantages in improving soil quality in alpine barren land. This study provides a scientific basis for ecological restoration and management of alpine barren lands.
Soil microorganisms and their metabolites play a critical role in the restoration of grassland ecosystems. This study focused on the Xiejiaogou mountain steppe in Urumqi, Xinjiang, to comparatively analyze the soil bacterial and fungal community structures between grazing-excluded and grazed areas. By integrating data on soil physicochemical properties, vegetation characteristics, and soil metabolomics, the study comprehensively explores the effects of grazing exclusion on soil microbial communities and their metabolic activities. The results showed that grazing exclusion significantly increased soil available phosphorus content and vegetation biomass. The dominant bacterial and fungal phyla were Actinobacteria and Ascomycota, respectively. Grazing exclusion generally altered the composition of soil microbial communities, specifically increasing the relative abundances of Proteobacteria, Methylomirabilota, Desulfobacterota, and Basidiomycota, while decreasing those of Chloroflexi, Nitrospirae, Mortierellomycota, Chytridiomycota, and Zoopagomycota. Moreover, both bacterial and fungal diversities were higher in the grazing-excluded areas than in the grazed areas. Differential analysis revealed that Methylomirabilota (P<0.05) and Desulfobacterota (P<0.01) had significantly higher relative abundances in the grazing-excluded areas, whereas Mortierellomycota and Zoopagomycota had significantly higher relative abundances in the grazed areas (P<0.05).Redundancy analysis indicated that strong associations existed between soil physicochemical factors and bacterial communities, and between vegetation characteristics and fungal communities. Metabolomics analysis further revealed that among the 8 differential metabolites, only neoxanthin-A exhibited higher abundance under grazing treatment, while strigol, isobavachin and naringenin as well as other compounds accumulated significantly under grazing exclusion. This study elucidated the potential mechanisms by which grazing exclusion promotes grassland ecological restoration through regulating soil microbial community structure and metabolic activities, thereby providing a theoretical basis for the scientific management of grassland ecosystems.
Grass seed is a fundamental input for forage-based livestock production and a key resource for ecological restoration. A healthy grass seed industry is essential for optimizing China's grain-cash crop-forage cropping structure and safeguarding food security. Based on long-term trade data from 1992 to 2024, this study characterized the evolution of trade in five categories of forage seed in terms of scale, structure, and distribution. Concentration indices and Hodrick-Prescott (HP) filtering were used to identify long-term trends and trade patterns. The results showed a persistent dual-concentration pattern in China's grass seed imports, with both imported seed types and source countries remaining highly concentrated. The trade deficit continued to widen, domestic substitution progressed slowly, and supply-chain risks remained prominent. Accordingly, a phased policy pathway comprising short-term risk mitigation, medium-term domestic substitution, and long-term strategic development is proposed to promote the high-quality development and revitalization of China's grass seed industry.
In this study, radicle-emerged seeds of the diploid hybrid mulberry cultivar 'Guisangyou 12' were used for polyploid induction. Different combinations of colchicine concentrations and treatment durations were evaluated to determine the optimal conditions for autotetraploid induction. In addition, morphological traits and leaf anatomical structures were compared between diploid and autotetraploid mulberry plants. The results showed that: (1) Compared with the control, seedlings from colchicine-treated seeds had shortened and thickened hypocotyls and radicles, indicating inhibited seedling growth. (2) The optimal induction treatment was soaking radicle-emerged mulberry seeds in 0.6 g/L colchicine solution for 3 h. Under these conditions, the seedling survival rate reached 25. 33%, the autotetraploid induction rate was 18. 67%, and the mixoploid induction rate was 2.00%. (3) Autotetraploid forage mulberry showed a ploidy-related advantage in vegetative growth. In terms of morphological traits, plant height, stem diameter, leaf length, and leaf width were increased by 19.92%, 45.45%, 21.63%, and 25.22%, respectively, compared with those of diploid plants. Regarding leaf anatomical characteristics, the thickness of leaf blade, upper epidermis, lower epidermis, palisade tissue, and spongy tissue increased by 77.32%, 116.92%, 132.14%, 89.18%, and 28.35%, respectively. In conclusion, this study established an efficient seed-soaking protocol for autotetraploid induction in forage mulberry, and tetraploid plants were successfully obtained, providing a theoretical basis and technical reference for ploidy breeding of forage mulberry.
