To elucidate how the dominant species Artemisia capillaris responds to grazing and nitrogen addition in a typical steppe, we conducted a long-term cold-season grazing experiment with four stocking rates, superimposed with four levels of warm-season nitrogen addition. At the population level, we measured morphological traits, reproductive traits, and aboveground productivity of A. capillaris. The results showed that the interactive effects of grazing and nitrogen addition significantly affected all measured variables (P<0.05). Plant height, seedling density, and aboveground biomass of A. capillaris exhibited unimodal responses to both grazing intensity and nitrogen addition, increasing first and then decreasing. By contrast, canopy diameter, reproductive branch density, and population density decreased with increasing grazing intensity, whereas growth point density declined with increasing nitrogen addition. Structural equation modeling revealed that nitrogen addition exerted a stronger regulatory effect than grazing on the aboveground biomass of A. capillaris and its proportion contribution to community biomass. Although both factors promoted biomass accumulation mainly by altering morphological traits, the decline in population density limited the enhancement of its competitive position within the community. Overall, A. capillaris responded to grazing and nitrogen addition through a strategy of enhanced vegetative growth, suppressed sexual reproduction, and elevated population renewal potential. These findings provide a theoretical basis for informing cold-season grazing management and nutrient regulation in typical steppe ecosystems.
To investigate the effects of changes in rainfall on soil microbial biomass in a desert steppe, a simulated rainfall experiment was conducted in Siziwang Banner, Inner Mongolia. A completely randomized block design was employed with four treatments: P1 (50% reduction in ambient rainfall), P2 (ambient rainfall), P3 (50% increase in ambient rainfall), and P4 (100% increase in ambient rainfall). Soil physicochemical properties and soil microbial biomass were measured across the different treatments. The results indicated that the P4 treatment significantly increased soil water content, pH, and total nitrogen content (P<0.05), whereas the P1 treatment significantly increased soil nitrate nitrogen and available phosphorus contents (P<0.05). Soil microbial biomass carbon and nitrogen peaked under the P3 treatment (P<0.05). Furthermore, soil water content, pH, soil organic carbon, total nutrients, and ammonium nitrogen all exhibited significant effects on soil microbial biomass, with ammonium nitrogen contributing the most (22.1%). In conclusion, nitrogen availability is the primary regulatory factor driving microbial community activity in the desert steppe under rainfall changes. These findings provide a theoretical basis for the adaptive management of the desert steppe in the context of climate change.
Karelinia caspia, a halophytic member of the Asteraceae family, has multiple ecological and economic values, particularly in saline-alkali land restoration, windbreak and sand fixation, forage production, and traditional medicinal applications. These attributes position it as a promising candidate plant resource in arid and semi-arid regions. To elucidate the genetic characteristics of K. caspia germplasm, 25 accessions of K. caspia germplasm were analyzed for genetic diversity using SSR molecular markers. The result showed that a total of 192 alleles were detected by 27 SSR primer pairs, with an average of 7.111 alleles per primer pair. The mean Shannon's information index (I) was 1.259, and the average polymorphism information content (PIC) was 0.541. Genetic similarity coefficients ranged from 0.271 to 0.694 (mean=0.484), indicating that the tested accessions possessed rich genetic diversity. Both UPGMA clustering and Structure-based population analysis classified the 25 accessions into five distinct groups. Furthermore, the primer combination P156+P58 was identified, which could accurately distinguish all tested accessions and enable the construction of DNA fingerprints and molecular identification codes. This study successfully developed SSR molecular markers suitable for K. caspia, which not only illustrated the rich genetic diversity and population genetic relationships of the tested accessions, but also provided an important theoretical basis for future germplasm identification, elite germplasm screening, and molecular breeding of K. caspia.
Agropyron cristatum × A. desertorum ‘Mengnong No.3’ is a new hybrid wheatgrass cultivar bred from progeny of crosses between A. cristatum and A. desertorum. It is characterized by high biomass and seed yield, an upright and compact plant architecture, strong tillering ability, and abundant leaves. To clarify its growth and developmental pattern, cytological characteristics, and genetic specificity, and to improve the basis for cultivar identification and application, this study investigated spike differentiation and development, cytological traits, and molecular identification of ‘Mengnong No.3’. Morphological observation, cytological identification, and SSR molecular markers were used to characterize its morphological traits and growth and developmental features. The results showed that young spike differentiation of ‘Mengnong No.3’ began at the early tillering stage in mid-April and ended at the heading stage in late May. According to morphological changes during growth and development, spike differentiation was divided into eight stages: initial growth cone stage, growth cone elongation stage, node stage, spikelet primordium emergence stage, glume primordium emergence stage, floret primordium emergence stage, stamen and pistil formation stage, and complete spike stage. Cytological identification of root tip cells showed that ‘Mengnong No.3’ was tetraploid, with 2n=4x=28 and a 1A karyotype. Five SSR molecular markers accurately distinguished ‘Mengnong No.3’ from the other tested cultivars, and fingerprint profiles were constructed.
This study aimed to determine the optimal EMS (ethyl methanesulfonate) concentration and treatment duration for chemical mutagenesis of seed stem of Pennisetum purpureum ‘Guiminyin’. A two-factor experiment was conducted with EMS concentration (0%, 0.1%, 0.3%, 0.5%, and 0.7%) and treatment times (2 h and 4 h). The results showed that EMS treatment had a significant inhibitory effect on both germination and rooting of seed stem, with the inhibitory effect on germination being stronger than that on rooting. Observed mutations predominantly involved leaf shape, leaf color, and leaf position. The suitable EMS mutagenesis conditions for seed stem of Pennisetum purpureum ‘Guiminyin’ were 0.3% EMS for 4 h.
Precipitation use efficiency (PUE) is a key indicator characterizing the water use capacity of grassland ecosystems. The partitioning characteristics of evapotranspiration (ET) components are directly associated with the processes of water consumption and productivity formation, which determine the potential for improving PUE. Current studies have mostly focused on the independent effects of single management practices such as irrigation, nitrogen application, and mowing, on PUE, lacking a systematic analysis of the synergistic regulation mechanisms of multiple factors. This study conducted a randomized block field experiment in the Songnen Plain from 2023 to 2025, against a background of a naturally water-limited condition driven by interannual variation in ambient water availability. Irrigation, nitrogen application, mowing, and their interactions were established. High-frequency monitoring and structural equation modeling (SEM) were combined to quantify the regulatory pathways of different management practices on the PUE of cultivated Leymus chinensis grasslands. The results showed that leaf area index (LAI) and plant density were the mediating variables driving the efficient water distribution in grassland, with plant density significantly affected by both nitrogen application and mowing, while LAI was primarily influenced by nitrogen application. There were significant differences in the regulatory pathways and effects of different management practices on PUE. Mowing could directly increase PUE and also exert a positive indirect effect on PUE by reducing the transpiration fraction; nitrogen application could not only promote PUE directly but also exert a positive indirect effect by increasing LAI and plant density; although irrigation could significantly alleviate soil water stress, promote plant transpiration, and optimize the partitioning of ET components, it had a direct negative effect on PUE; Mowing twice combined with nitrogen application was the optimal combination for improving PUE, which could synergistically optimize the vegetation structure and water distribution pattern, and effectively alleviate water stress. This study clarified the intrinsic mechanism of the synergistic regulation of PUE in cultivated L. chinensis grasslands by irrigation, nitrogen application, and mowing, and provided a scientific basis for the efficient management of grassland water resources in semi-arid regions and the sustainable management of cultivated grasslands under climate fluctuations.
A field experiment was conducted to evaluate the effects of row spacing and nitrogen fertilizer application rate on the production performance of alfalfa grown in saline-alkali soil of the Hexi Oasis Irrigation Area of Gansu Province, aiming to identify suitable cultivation regimes and cultivars for this region. Using a split-split plot design, four alfalfa cultivars, including Gannong No.5 (G5), Gannong No.6 (G6), Gannong No.7 (G7) and Gannong No.8 (G8), were tested under two row spacing (10 cm, H10; and 30 cm, H30) and four nitrogen rates (0, 90, 180 and 240 kg/hm2, designated N0, N90, N180, N240, respectively). In single-factor analyses, H30 resulted in greater plant height and stem diameter, whereas H10 produced higher forage yield. Among nitrogen levels, N180 gave the best overall productivity; and among cultivars, G6 exhibited the best comprehensive production traits. For two-way interaction, the row spacing×nitrogen rate interaction showed that N180 achieved the highest total hay yield at H10; the row spacing×cultivar interaction indicated that G6 outperformed others at H10; and the cultivar×nitrogen rate interaction revealed that G6 yielded the most under N180. For the three-way interaction (row spacing×nitrogen rate×cultivar) G6 again produced the highest total hay yield under the combination of H10 and N180. In conclusion, cultivar G6 produced the highest forage yield when grown at a row spacing of 10 cm and a nitrogen fertilizer rate of 180 kg/hm2 in the saline-alkali soil of the Hexi Oasis irrigation area, Gansu Province.
Leymus chinensis has wide ecological adaptability, high forage yield, good nutritional value, and strong stress resistance. Owing to its considerable ecological and economic value, this species has broad application prospects in animal husbandry and ecological restoration. This study investigated the effects of planting density and water and fertilizer management on forage yield, seed yield, and nutritional quality of L. chinensis ‘Xiwuzhumuqin’. The results showed that, under irrigation that maintained soil water content at 50% to 60% of field capacity, fresh forage yield and seed yield were 28.75% and 25.00% higher than those under the control, respectively. Acid detergent fiber and neutral detergent fiber contents also increased significantly by 8.10% and 4.84%, respectively. The control was conventional field management, with 30 cm row spacing and irrigation at the spring regreening, jointing, and fruit-ripening stages to approximately 50% of field capacity. Applying urea (200 kg/hm2) at both the jointing and post-fruiting vegetative stages increased fresh forage yield by 94.02% and crude protein content by 69.45% compared with the control. Sparse planting with 50 cm row spacing increased seed yield by 35.00%, whereas dense planting with 10 cm row spacing decreased seed yield by 40.00%. Applying compound fertilizer and urea(200 kg/hm2 each) at the jointing stage and urea at the post-fruiting vegetative stage increased spikelets number, inflorescence width by 19.03%, 31.74% and crude protein content by 53.01% compared with the control. Based on correlation analysis and principal component analysis, applying 200 kg/hm² urea fertilizer at both the jointing and post-fruiting vegetative stages, or irrigation, is recommended to improve the yield and nutritional quality of L. chinensis.
Screening suitable cereal-legume intercropping patterns and species combinations is important for alleviating forage shortages and protein deficiency in the Longzhong Loess Plateau. In Longxi County, Gansu Province, forage maize was intercropped with three leguminous forages, namely soybean, lablab bean, and cowpea. Two intercropping patterns and three species combinations were established, including adjacent-row intercropping, maize || soybean (MS1), maize || lablab bean (ML1), and maize || cowpea (MC1), and within-row intercropping, maize + soybean (MS2), maize + lablab bean (ML2), and maize + cowpea (MC2). Sole crops of each forage species were used as controls. The effects of different intercropping combinations on mixed-system yield and forage quality were evaluated. The results showed that MC2 had the largest stem diameter, at 38.76 mm, and the most favorable stem-to-leaf ratio, at 1.24. ML1 had the highest total hay yield, reaching 27 438 kg/hm², which was 31.32% and 369.09% higher than those of sole maize and sole lablab bean, respectively. The land equivalent ratio was greater than 1 in all intercropping patterns and combinations, with the highest value observed in ML1 (1.69). Intercropping significantly increased group protein yield, with ML1 reaching the highest value of 2 223 kg/hm², which was 42.31% and 146.67% higher than those of sole maize and sole lablab bean, respectively. Grey relational analysis showed that the comprehensive performance ranked as ML1>MC1>MC2>ML2>MS1>MS2. Overall, adjacent-row intercropping of forage maize and lablab bean is recommended as the preferred pattern for the Longzhong Loess Plateau, followed by adjacent-row intercropping of forage maize and cowpea and within-row intercropping of forage maize and cowpea.
To investigate the molecular mechanisms underlying root rot resistance in alfalfa (Medicago sativa L.) and identify candidate resistance-related genes, the resistant cultivar ‘Concept’ and the susceptible cultivar ‘Zhongmu No.1’ were used in this study. Roots collected 7 d after inoculation with Fusarium oxysporum were subjected to transcriptome sequencing using the Illumina NovaSeq X Plus platform. The results showed that compared with uninoculated controls, 5 125 differentially expressed genes (DEGs) were detected in the resistant cultivar ‘Concept’ at 7 d post-inoculation, markedly more than the 3 111 DEGs detected in the susceptible cultivar ‘Zhongmu No.1’. This result indicated cultivar-specific differences in transcriptional regulation after pathogen infection. GO enrichment analysis showed that the DEGs were mainly associated with biological processes related to metabolism, stress responses, and signal transduction. KEGG enrichment analysis showed that the DEGs were mainly enriched in pathways related to metabolism, plant hormone signal transduction, the mitogen-activated protein kinase (MAPK) signaling pathway, and plant-pathogen interaction. Seven DEGs, including two BAK1 genes and five PR1 genes, were co-enriched in three disease-resistance-related pathways, namely MAPK signaling, plant-pathogen interaction, and plant hormone signal transduction. These genes showed two expression patterns: conserved up-regulation in both cultivars and specific up-regulation only in the resistant cultivar. The divergent expression trends between the two cultivars provide important molecular clues for explaining differences in alfalfa resistance to root rot. In addition, 27 differentially expressed transcription factors from five families, including WRKY, BHLH, TIFY, AP2-EREBP, and GRAS, were identified. Six DEGs were randomly selected for RT-qPCR validation, and their expression trends were consistent with the RNA-seq results, confirming the reliability of the transcriptome data.
To address the challenges posed by the fragile ecological environment, poor overwintering ability, impaired growth, low yield of alfalfa, and extremely low land-use efficiency in sodic saline-alkali soils of cold regions, this study was conducted in alfalfa fields on such soils in Daqing City, Heilongjiang Province. Cattle bedding cover was applied at four rates (0, 6 000, 12 000 and 18 000 kg/hm2). During the alfalfa growing season, we monitored dynamic changes in soil pH, moisture, organic matter, alkali-hydrolyzable nitrogen, available phosphorus, available potassium, and electrical conductivity in the 0-40 cm soil layer, as well as the overwintering survival and growth performance of the alfalfa. The results showed that cattle bedding cover effectively reduced soil pH, while increasing soil moisture, organic matter, electrical conductivity, alkali-hydrolyzable nitrogen, available phosphorus, and available potassium. The optimal application rate was 12 000 kg/hm2, which yielded the best overall improvements. In 2024 and 2025, under a coverage treatment of 12 000 kg/hm², the average plant height of three alfalfa cuts increased by 18.01% and 17.99% compared to the control, the number of branches increased by 16.40% and 28.11%, fresh grass yield increased by 25.20% and 33.64%, and hay yield increased by 26.22% and 32.27% (P<0.05). The overwintering rate increased by 11.40% and 10.62%, respectively. Overall, cattle bedding cover can effectively regulate soil pH, improves soil physicochemical properties, and significantly boost forage yields. These findings provide a theoretical basis and technical support for achieving high and stable alfalfa yields in sodic saline-alkali soils and for the remediation of such soils on the Songnen Plain.
The development of national grassland parks (NGPs) is an important measure for improving the protected area system, enhancing grassland ecological protection and restoration, and promoting the rational use and sustainable development of grasslands under the framework of ecological civilization. Establishing a theoretical and technical system for the construction and management of national grassland parks provides the basis for advancing their planning, construction, and efficient management, as well as for strengthening their demonstration role in grassland protection, restoration, and utilization. Based on planning and construction practices and related research, this paper systematically explains the concept, conservation targets, functional positioning, establishment criteria, and naming rules of NGPs. It further discusses the basic conditions, planning principles, boundary delineation, functional zoning, and construction contents involved in NGP planning and construction. A refined zoning and management framework is proposed for ecological conservation areas, recreation and sightseeing areas, grassland-livestock production demonstration areas, and comprehensive service areas. Six major engineering components are also clarified, including five special construction projects: ecological protection and restoration, rational use, nature education and science popularization, scientific research and monitoring, coordinated community development, as well as supporting system projects. The resource conditions, construction progress, and existing problems of 39 pilot NGPs in China are then analyzed. On this basis, countermeasures are proposed, including strengthening top-level design and planning guidance, improving standards and technical systems for construction and management, enhancing high-level protection, restoration, monitoring, and evaluation, promoting industrial integration and high-quality green development, and improving public services and management capacity. The findings provide a reference for the planning, construction, and management of national grassland parks.
Solanum rostratum is an annual herbaceous plant belonging to the genus Solanum of the Solanaceae family. As a highly invasive weed in northern China, it poses a serious threat to the biodiversity and ecological balance of invaded areas due to its remarkable fecundity and environmental adaptability. Nevertheless, the plant possesses abundant biomass resources and thus holds potential for resource-oriented utilization. Based on a comprehensive review of the literature over the past 40 years (1985-2025), a total of 58 compounds that have been isolated and identified from S. rostratum were systematically cataloged and consolidated for the first time, principally comprising alkaloids, flavonoids, steroidal saponins, and terpenoids. These compounds exhibited a range of biological activities, including insecticidal, antibacterial, anti-tumor, allelopathic, and antioxidation effects. This review summarized the research progress on chemical constituents and biological activities of S. rostratum and its application prospects in plant-derived green pesticides and functional feed additives. This work aims to lay a foundation for the resource utilization of S. rostratum and to provide novel insights for the research and practice of transforming invasive alien plants from nuisances into beneficial bioresources.
