Using 370 Agropyron germplasms as experimental materials, this study systematically investigated their genetic diversity using 31 phenotypic traits and multiple statistical methods, including coefficient of variation, genetic diversity index, cluster analysis, correlation analysis, and grey relational analysis. Additionally, QGA software was employed to simulate and analyze genetic distance, sampling ratio, and clustering algorithms to determine optimal parameters for core germplasm construction. The effectiveness of the core subset was verified through principal component analysis and genetic diversity parameters. Results indicated significant phenotypic differentiation and rich genetic diversity in Agropyron germplasms. Quantitative traits (23 in total, with an average diversity index of 1.867) served as the primary carriers of genetic diversity, with their genetic diversity index was significantly higher than that of qualitative traits (1.328). Phenotypic correlations revealed a "source-sink-flow" coordinated development mechanism: leaves and stems exhibited coordinated growth; spike length was positively correlated with spikelet and floret numbers but negatively correlated with spikelet density, providing a basis for ecological adaptive breeding. Cluster analysis categorized the materials into three characteristic germplasm types: Type Ⅰ (24 resources, characterized by tall plants, long roots, and long spikes), Type Ⅱ (123 resources, emphasizing spike and leaf development), and Type Ⅲ (223 resources, with high spikelet density and numerous glume veins). Grey relational analysis identified seven core evaluation indicators: spikelet number, florets per spike, spike width, first rachis internode length, leaf color, leaf sheath length, and second internode stem diameter. Fifteen comprehensively excellent materials (GB3, BB34, MB15, BB55, XB6, MB25, MB32, GB11, MB7, SB55, SB52, BB68, XB3, BB110, XB2) were selected. A core germplasm consisting of 92 accessions was constructed using "Mahalanobis distance+deviation sampling+sum of squared deviations+25% sampling ratio." This core subset included all 15 excellent materials, achieving an organic unity of genetic diversity conservation (MD=0, CR=100%) and superior trait screening (VD=41.935%, VR=115.413%). Principal component analysis confirmed high consistency between the core germplasm and the original population in genetic structure (core germplasm cumulative contribution rate: 73.014%; original population: 64.407%). This study integrates phenotypic diversity analysis, grey relational evaluation, and core germplasm construction techniques, providing theoretical basis and material support for the efficient utilization and genetic improvement of Agropyron germplasm resources.
Lead contamination is a major abiotic stress that reduces crop yield, causes plant death, and degrades the environment. Red clover (Trifolium pratense) is an important forage legume with substantial potential for lead tolerance. Based on previously generated transcriptome data from red clover exposed to different lead concentrations, the present study identified and characterized the LHC gene family using bioinformatics approaches. A total of 21 TpLHC genes were identified and assigned to the LHCA (5 members) and LHCB (16 members) families. Phylogenetic analysis of TpLHC proteins and their homologs in Arabidopsis thaliana and Medicago truncatula classified the TpLHCA and TpLHCB families into five and seven subfamilies, respectively. Subcellular localization analysis predicted that most TpLHC proteins were localized to chloroplasts, whereas TpLHCA6 and TpLHCB7 were localized to the plasma membrane. Expression analysis under 0, 500, 1 000, 2 000, and 3 000 mg/kg lead treatments showed that, after 45 d of exposure, expression of all TpLHCB8 subfamily members was strongly suppressed under 500 mg/kg lead stress, TpLHCA1, TpLHCA6, TpLHCB1.1, TpLHCB1.6, TpLHCB4.1, TpLHCB5, and TpLHCB7 were upregulated under 3 000 mg/kg lead stress. qRT-PCR analysis showed that, after 48 h of exposure to 1 000 mg/kg lead, all LHCA family members except TpLHCA6 were downregulated. Among the LHCB genes, except for TpLHCB1.2 and TpLHCB7, the expression levels of the remaining members increased at 48 h under stress compared to those under non-stress conditions, suggesting that LHCB genes may be more strongly associated with lead-stress tolerance.
Carex breviculmis is a perennial herbaceous plant in the Cyperaceae family, characterized by strong self-regeneration capacity, shade tolerance, drought tolerance, and barrenness tolerance, demonstrating considerable potential for landscape application in shaded environments. To elucidate the regulatory role of different red/far-red ratios (R/FR) as shading signals on the physiological adaptation mechanisms of C. breviculmis, gradient R/FR treatments (1.2, 0.6, 0.4, and 0.2) were applied, with R/FR=1.2 serving as the control, and the responses of phenotype, photosynthetic characteristics, and antioxidant system were systematically analyzed over a 20-day treatment period. The results showed that under a light intensity of 200 μmol/(m2·s), R/FR=0.4 represented the optimal growth condition. After 10 days of treatment, plant height, leaf length, and leaf width under R/FR=0.4 increased significantly by 14.43%, 25.43%, and 13.25%, respectively, compared with the control, and the net photosynthetic rate reached 6.48 µmol/(m2·s), indicating a pronounced photosynthetic advantage. Chlorophyll fluorescence analysis revealed that the maximum photochemical efficiency of PSⅡ (Fv/Fm) remained stable between 0.82 and 0.83, suggesting that PSⅡ maintained functional integrity and high light-energy utilization efficiency under low R/FR light conditions. Concurrently, biochemical analysis demonstrated that after 20 days of treatment at R/FR=0.4, malondialdehyde (MDA) content increased by 45.35% relative to day 0, and the activities of peroxidase (POD), catalase (CAT), and superoxide dismutase (SOD) increased by 142.36%, 52.06%, and 778.30%, respectively; proline accumulation increased by 52.09% compared to day 0. These findings indicate that low R/FR induced an increase in stomatal aperture and simultaneously activated the antioxidant enzyme and osmotic adjustment systems, which jointly mitigated oxidative stress imposed by the light quality. This study reveals the physiological adaptation strategies of C. breviculmis under low light quality conditions and provides a theoretical basis for its rational application in shaded green spaces.
To identify high-quality salt-tolerant germplasm of timothy (Phleum pratense), 21 timothy accessions from China and abroad were evaluated under 120 mmol/L NaCl stress, and their differential responses in morphological characteristics, physiological indices and photosynthetic parameters were investigated. The results showed that salt stress significantly (P<0.05) decreased plant height, leaf area, K+ content, root activity, leaf relative water content, chlorophyll content, carotenoid content, transpiration rate, net photosynthetic rate, water use efficiency, intercellular CO2 concentration, and stomatal conductance, while it significantly increased root-to- shoot ratio, Na+ content, Na+/K+ ratio, stomatal limitation value, malondialdehyde (MDA) content, proline content, soluble sugar content, soluble protein content, and the activities of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT). The comprehensive evaluation revealed that accesssion 9451 exhibited the highest salt tolerance, accession 8383 the lowest, and the other materials fell between these two extremes. Regression analysis further identified net photosynthetic rate, chlorophyll content, stomatal conductance, leaf area, MDA content and intercellular CO₂ concentration as reliable indicators for screening salt-tolerant timothy germplasm. These findings provide a theoretical reference for salt-tolerant breeding and germplasm enhancement in timothy.
This study evaluated the long-term forage productivity and production sustainability of alfalfa in the Jinzhong region of Shanxi Province and examined their responses to climatic factors. Field experimental data were used to further validate the ability of the Agricultural Production Systems sIMulator (APSIM) model to simulate soil water storage in alfalfa fields. Long-term scenario simulations were then conducted for three widely grown WL-series alfalfa cultivars using 30 years (1985—2014) of historical weather data from multiple sites in the region. The results showed that APSIM satisfactorily simulated soil water storage, with a normalized root mean square error below 20.60%. Sites characterized by high precipitation and low air temperature had the highest forage yield, water consumption, and water productivity and the most favorable coefficients of variation and sustainable yield indices. Under low-precipitation and high-temperature conditions, cultivars with greater thermal-time requirements before flowering achieved higher forage yields and sustainable yield indices. Across the Jinzhong region, alfalfa yield, water consumption, and water productivity were positively correlated with growing-season precipitation and negatively correlated with air temperature (P<0.05), whereas the sustainable yield index was positively correlated with growing-season precipitation (P<0.05). These results indicate that long-term alfalfa production in the Jinzhong region is primarily constrained by precipitation. Selecting cultivars with greater thermal-time requirements and stronger drought resistance may improve productivity and production sustainability under potential high-temperature and summer-drought conditions.
To evaluate the effects of nitrogen (N) and phosphorus (P) fertilization on seed yield and yield components of Elymus sibiricus in alpine regions, the cultivar 'Qingmu 2' was used as the experimental material. Four N levels (N0: 0 kg N/hm2, N1: 60 kg N/hm2, N2: 90 kg N/hm2, N3: 120 kg N/hm2) and four P levels (P0: 0 kg P2O5/hm2, P1: 30 kg P2O5/hm2, P2: 60 kg P2O5/hm2, P3: 90 kg P2O5/hm2) were established to assess seed yield and yield components, and economic returns. The results showed that under combined N and P application, spikelet number per reproductive tiller, seed number per spike, spike length, thousand seed weight, and seed yield of E. sibiricus first increased and then decreased with the increasing P application rate. Among all treatments, N1P2 (60 kg N/hm2+60 kg P2O5/hm2) showed the best overall performance, with a seed yield of 1 654.69 kg/hm2, representing a 74.8% increase over the unfertilized control. The corresponding economic return reached 12 074.41 CNY/hm2. Structural equation modeling indicated that the positive effect of N and P fertilization on seed yield was mainly mediated through an increase in tiller number. Comprehensive evaluation using the Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) identified N1P2 as the optimal fertilization regime for E. sibiricus seed production in alpine regions. These findings provide a theoretical basis and technical support for efficient seed production of E. sibiricus in alpine regions.
Oat (Avena sativa L.) is a major forage crops in the agro-pastoral ecotone of northern China. Its productivity is often co-limited by both water and nutrient availability, and the region is characterized by diverse soil types. However, the mechanisms underlying the interactive effects of soil type and water-fertilizer management on yield formation and nutrient uptake in oat remain poorly understood. Based on a soil translocation network experiment platform established across the agro-pastoral ecotone, this study investigated the effects of irrigation and fertilization on biomass and nitrogen (N) and phosphorus (P) uptake of oat grown in four typical soil types: chernozem, loessal soil, chestnut soil, and aeolian sandy soil. The results indicated that: (1) Irrigation or fertilization alone optimized aboveground biomass allocation, increased aboveground biomass, and thereby enhancing N and P uptake in oat. (2) Water-fertilizer coupling significantly increased stem and leaf biomass in all four soil types (P<0.05) and significantly increased N and P uptake in chernozem, loessal soil, and chestnut soil (P<0.05). (3) Structural equation modeling further revealed that water-fertilizer coupling enhanced the accumulation of stem and leaf biomass, which increased total aboveground biomass and consequently drove greater N and P uptake. Overall, soil type was a key factor determining oat responses to water and fertilizer management. Therefore, site-specific water and fertilizer based on soil properties and crop demands should be implemented to effectively improve oat productivity and water use efficiency in the agro-pastoral ecotone of northern China.
This study investigated the interactive relationship between plant community structure and function during the ecological restoration of aeolian pit desertified grassland, aiming to identify the dominant factors influencing restoration effects and provid a theoretical basis for optimizing restoration strategies. Field surveys were conducted in typical aeolian pit desertified grasslands in Xilingol League and Tongliao City to collect plant community characteristics data. The community importance index, species diversity indices, and functional stability indicators were calculated, and grey relational analysis together with advantage analysis was employed for comprehensive evaluation. The results revealed that, during the restoration process, the influence of plant community function (represented by the importance index) on community structure (represented by species diversity indices) was significantly stronger than the reverse influence of structure on function, indicating a marked asymmetric interaction. The Simpson dominance index and Shannon-Wiener index were the dominant structural factors driving changes in community function, with their relative importance exceeding that of species richness. Community functional stability was found to be highly correlated with species diversity structure. Among all structural factors, the Simpson dominance index and the Shannon-Wiener diversity index exhibited the most prominent correlations with functional stability, underscoring the close intrinsic linkage between structural attributes and stability. These findings collectively suggest that, during the initial restoration phase of sandy grasslands, priority should be given to the rapid enhancement of vegetation coverage and overall ecosystem functioning. By driving structural optimization through functional restoration, the community can be steered toward a successional trajectory of stabilized structure.
Accurate selecting phenological stages is crucial to overcoming the bottleneck in monitoring and identifying the invasive plant Solanum rostratum against complex grassland backgrounds. To elucidate the spectral responses dynamics of S. rostratum during invasion and to determine its optimal monitoring phenological window, this study focused on S. rostratum in the typical steppe of Bairin Right Banner, Inner Mongolia Autonomous Region, and conducted multi-temporal monitoring at five key phenological stages: seedling, early flowering, full flowering, green fruit, and senescence. Using anmanned aerial vehicle (UAV)-based multispectral remote sensing imagery, the identification accuracies of S. rostratum at different phenological stages were compared. The results revealed that: (1) The identification accuracy exhibited a unimodal pattern along the phenological progression, with the best performance achieved at the early flowering stage, reaching an overall accuracy of 92.2%; (2) Significantly differences in spectral separability existed among phenological stages, and canopy reflectance changes triggered by inflorescence emergence were one of the primary drivers of accuracy variation; and (3) Feature contribution analysis showed that the Near-Infrared Reflectance of Vegetation (NIRv) and Kernel Normalized Difference Vegetation Index (kNDVI) played critical roles in distinguishing S. rostratum from background features, effectively mitigating the interference of mixed pixels in complex grassland scenes. In conclusion, the rational selection of phenological stages is a key factor for UAV-based monitoring of the invasive plants S. rostratum, and these findings can provide a scientific basis for temporal phase selection in large-scale monitoring and early warning of invasive plants.
Kengyilia species are key components of alpine meadow ecosystems in China. To assess the effects of climate change on their potential distributions, four representative Kengyilia species: K. tahelacana, K. laxiflora, K. thoroldiana, and K. mutica were selected. An optimized MaxEnt model was then used with occurrence records and environmental variables from multiple periods to project changes in suitable habitat and centroid migration. The results showed that mean area under the receiver operating characteristic curve (AUC) ranged from 0.828 to 0.864, indicating high predictive accuracy. Elevation, temperature seasonality, and annual temperature range were the dominant environmental variables affecting species distributions. Under current climatic conditions, suitable habitats for all four species were concentrated on the Qinghai-Xizang Plateau and in surrounding alpine regions. Compared with the current region, the areas of suitable habitats for the four species under future climate scenarios show fluctuating changes. The suitable habitats of K. tahelacana and K. thoroldiana expanded, while those of K. laxiflora and K. mutica contracted.The centroids generally shifted towards the northeast with higher latitudes and altitudes. These shifts were greater under the high-emission SSP5-8.5 scenario.
The experiment was conducted to evaluate the silage quality and protein structure of five alfalfa (Medicago sativa L.) cultivars (Spreader, Beilin 201, WL298, Beilin 202, and Womu No.1) using wet chemistry analysis and spectroscopic techniques, so as to provide a reference for the scientific utilization of alfalfa. The results showed that after ensiling, Beilin 201 exhibited the highest lactic acid content (7.52% DM) and the lowest contents of ammonia nitrogen (1.18% DM), acetic acid (0.15% DM), and propionic acid (0.67% DM), while no butyric acid was detected in any treatments. The crude protein (CP) content of all cultivars exceeded 21.84%, with Beilin 201 being the highest. The in vitro dry matter digestibility (IVDMD) of Spyder was significantly higher than that of the other cultivars, and WL298 had the highest in vitro crude protein digestibility (IVCPD). Protein secondary structure analysis revealed that after ensiling, the β-sheet content increased, whereas the contents of random coil, α-helix, and β-turn decreased. Beilin 201, Beilin 202, and WL 298 displayed higher random coil contents than Womu No.1, while the β-turn content showed an opposite trend. Redundancy analysis (RDA) indicated that β-sheet was negatively correlated with soluble protein (SP) and IVCPD, whereas random coil, α-helix, and β-turn were positively correlated with SP. In conclusion, cultivar has a significant effect on the silage quality and protein secondary structure of alfalfa. Beilin 201 exhibited superior silage quality, characterized by the highest lactic acid and crude protein contents and the lowest ammonia nitrogen content. The ensiling process induced marked changes in protein secondary structure, with the β-sheet proportion increasing substantially to become the dominant conformation. These findings provide a theoretical basis for exploring quality changes in silage from the perspective of protein structure.
To determine how the inoculation concentration of Lactobacillus plantarum affects microbial populations, acid production, and aflatoxin content during oat ensiling, oat stems and leaves harvested at the milk stage were ensiled without inoculant (CK) or with L. plantarum Q39 at 1 × 104, 1 × 105, 1 × 106, or 1 × 107 CFU/mL (C4, C5, C6, and C7, respectively). Key parameters were measured after 0, 3, 5, 7, 14, and 30 d of ensiling and during aerobic exposure following 90 d of ensiling. The results showed that the pH of all treatments decreased rapidly during the first 3 d and then declined more slowly before stabilizing. At 30 d, C5 had the lowest pH (3.90), which was significantly lower than that of CK (P<0.05). Inoculation increased organic acid concentrations and lactic acid bacterial counts, with the greatest increases observed in C5 and C6. The lactic acid bacteria counts in the C5, C6, and C7 treatments were significantly higher than those in the CK at 30 d (P<0.05), and molds of C5 and C6 treatments were undetectable after 3 d of ensiling. At 30 d, aflatoxin concentrations were significantly lower in all inoculated treatments than in CK (P<0.05), with the lowest values observed in C6 and C7. During aerobic exposure, all inoculated silages showed smaller increases in pH, less mold growth, lower aflatoxin accumulation, and reduced losses of organic acids and lactic acid bacteria than CK, with the most pronounced effects in C6 and C5. These results indicate that L. plantarum Q39 improved fermentation stability and resistance to aerobic deterioration. Membership function analysis integrating the ensiling and aerobic-exposure phases identified 1 × 106 CFU/mL as the optimal inoculation concentration for maximizing both fermentation quality and aerobic stability.
In order to analyze the variation patterns of nutrient content in gramineous and leguminous forage products during storage， this study took the common oat and alfalfa cubes （32 mm × 32 mm × 32 mm） as the research objects in Gar County， Ngari Prefecture， Xizang Autonomous Region， and sampled and measured the crude protein （CP），ash， crude fat （EE），neutral detergent fiber （NDF） and acid detergent fiber （ADF） content of the two grass cubes at the 0， 30， 60， 90， 120， 150 and 180 days of storage， and recorded the daily temperature and humidity simultaneously. The results showed that： During the 180-day storage period， the storage temperature showed a decreasing trend with the extension of storage time， reaching the lowest point on the 90th day and then increased. The overall storage humidity showed a decreasing trend with the extension of storage time， reaching the lowest point on the 180th day. Correlation analysis and stepwise regression analysis indicated that there were a moderate negative correlation （r=-0.727 and -0.567） and a significant linear relationship （R 2=0.529， P=0.003； R 2=0.322， P=0.034） between the contents of CP and NDF in oat cubes and storage temperature. There was a moderate negative correlation （r=-0.760， and -0.608） and a significant linear relationship （R 2=0.755， P=0.001） between the ash content of oat cubes and storage temperature and humidity. There were a moderate negative correlation （r=-0.661） and a significant linear correlation （R 2=0.437， P=0.010） between the CP content of alfalfa cubes and storage temperature. Further linear regression analysis， for every 1 ℃ increase in storage temperature， the CP and NDF contents of oat cubes decreased by 0.018% and 0.068%， respectively. When the storage temperature was constant， for every 1 ℃ increase in the storage relative humidity， the ash content of oat cubes decreased by 0.014%. When the relative humidity during storage was constant， for every 1 ℃ increase in storage temperature， the ash content of oat cubes decreased by 0.018%. For every 1 ℃ increase in storage temperature， the CP content of alfalfa cubes decreased by 0.019%. In conclusion， the contents of CP and NDF of the oat cubes were mainly affected by storage temperature， while the ash content was affected by both storage temperature and humidity. The CP content of alfalfa cube was affected by storage temperature， while other nutrients were not affected by storage temperature and humidity. In production practice， high-density grass products such as cubes of grasses or leguminous forage should be stored in warehouses with different temperatures and humidity， and the storage time should be shortened as much as possible to reduce nutrients loss.
