Grassland Science最新文献

The use of unmanned aerial vehicles for remote sensing is an effective method for monitoring crop growth, particularly for tall crops such as maize. High-resolution imagery obtained from unmanned aerial vehicles enables the measurement of plant height, which is a critical indicator of crop growth. However, a reference plant height is required to assess growth. This study aimed to develop a model to predict the reference height for growth assessment using temperature data. Furthermore, a methodology was proposed to estimate model parameters from the relative maturity, thus enabling adaptation to a range of maize varieties. In 2022 and 2023, maize plant height was measured using an unmanned aerial vehicle at two flying altitudes (40 and 100 m) several times for 12 varieties with varying relative maturity. Moreover, a regression model was developed to predict the silking stage and identify the optimal sensing time 1 week before the silking stage. The results showed that the growth rate was not statistically different among the varieties, indicating that maximum plant height was determined by the duration of the growth period. A growth model was developed based on these results. The root mean square error (RMSE) for the model was 0.16 and 0.15 m for data sets from 40- and 100-m altitudes, respectively. In estimating plant height, this growth model performed marginally better than the logistic curves used in existing studies. Additionally, a linear relationship was observed between relative maturity and the parameters of the developed growth model. Consequently, the newly developed growth model can predict the plant height for new varieties because the parameters of the model can be inferred from the relative maturity.

To explore the molecular mechanisms underlying drought-stress response in Allium mongolicum seeds, Agramma mongolicum seeds were used as the experimental material in this study. Drought stress in the seeds was induced using 20% PEG-6000. The germination indicators of A. mongolicum seeds were determined at the early (5d) and the later stage of stress (10d). Transcriptome sequencing was performed for four treatment groups: soak seeds in distilled water for 5 days (5d CK), soak seeds in 20% PEG for 5 days (5d 20% PEG), soak seeds in distilled water for 10 days (10d CK) and soak seeds in 20% PEG for 10 days (10d 20% PEG). The values of the germination indicators of the seeds were significantly reduced as the stress duration increased. In the early and later stages of stress, 15,759 and 18,122 genes were differentially expressed, with 5,759 and 6,461 genes being significantly upregulated, 6,264 and 5,938 genes being significantly downregulated, respectively. According to the results of the Gene Ontology (GO) enrichment analysis, differentially expressed genes (DEGs) were primarily enriched in the cytoplasmic translation process and ribosome-related structures. KEGG enrichment analysis results showed that the DEGs were mainly enriched in ribosomes, pyruvate metabolism, glycolysis/gluconeogenesis, the TCA cycle and cysteine and methionine metabolism pathways. The DEGs were significantly enriched in C2H2, AP2/ERF-ERF, bZIP and MYB transcription factor families. After drought-stress treatment, nine genes belonging to the glycolysis/gluconeogenesis pathway were differentially expressed. The drought tolerance in A. mongolicum seeds is largely associated with the scale and nature of gene expression changes under stress. A. mongolicum seeds may adapt to drought stress via the glycolysis/gluconeogenesis and TCA cycle pathways. The results of this study provide a reference for further exploring the molecular regulatory mechanisms underlying the drought-stress response of A. mongolicum seeds.

Licorice is an important Chinese medicinal herb, and its above-ground parts are also useful as a legume forage. However, limited information is available on how the harvesting frequency impacts plant productivity, forage nutritional value, root growth parameters and medicinal compounds. This study aimed to determine the optimal harvesting frequency to maximize both the forage productivity and medicinal compounds in licorice by harvesting once (HF1), twice (HF2) or three times (HF3) per year in China Xinjiang Kuerle over 2 years. The results revealed that the dry matter yield and crude protein (CP) yield were greater in the HF3 treatment than in the other treatments. In HF3, the CP and crude fat contents were also relatively high, whereas the neutral detergent fiber (NDF), acid detergent fiber (ADF) and acid detergent lignin (ADL) contents were relatively low. In three-year-old licorice, increasing the harvesting frequency decreased the growth of the underground root system and the production of medicinal compounds. Compared with those in the HF1 treatment, the dry weights of single roots decreased by 16.65% and 47.08% in HF2 and HF3, respectively. In HF3, the glycyrrhizic acid content in the licorice roots was 0.48 ± 0.01%, which was significantly lower in HF1 (20%), whereas it was 0.6 ± 0.01% of that in HF1, leading to a decreased liquiritin content of approximately 49.28%. These results indicate that increasing the harvesting frequency during the growing period can not only increase the forage yield but also improve the forage quality. The CP content of forage increases with increasing harvest frequency, whereas antinutritional factors such as lignin and total tannins decrease; additionally, these effects impact the root mass and contents of medicinal compounds of licorice.

This study aims to determine how plant communities and soil characteristics respond to topography in three habitats in the basin unit of the Yellow River source zone. Based on the data of field plant community species and soil factors investigated in a typical alpine meadow, we established the relationship between plant community, soil characteristics and typical topographic habitats via correlation analysis, redundancy analysis (RDA), and structural equation modelling. The results showed that: (1) Shannon-Wiener diversity index and Pielou evenness index of the alpine meadow plant community are the highest in marshland habitat, which significantly increased by 44.97% and 48.34% over those of sunny habitat (P < 0.05); (2) Soil water content (SWC) and organic carbon (SOC) content in different habitats were the highest in marshland habitat, which were 87.05% and 155.31 g/kg, respectively, significantly higher than in sunny habitat (P < 0.05); (3) A large number of significant correlations (P < 0.05) exist between community characteristics and their stoichiometric ratios, soil physical and chemical properties and soil enzyme activity. RDA analysis revealed that the hydrogen (H) content of aboveground parts of plants, carbon-nitrogen ratio (C/N) of underground parts of plants, nitrogen-phosphorus ratio (N/P) of soil, the nitrate nitrogen (NH₄⁺-N) content of soil and N-acetyl-glucosaminidase (NAG) enzyme activity exhibit the greatest influences on community characteristics, with a contribution rate of 70.0%, 51.4%, 79.4%, 72.2% and 91.3%, respectively, all reaching the significant level (P < 0.05). Soil nutrients affect plant diversity and productivity by affecting the nutrients and stoichiometry of aboveground and underground plants. This study shows that the change in topographic position can lead to differences in plant community characteristics and soil physical and chemical properties and has an important impact on the changes in extracellular enzyme activity and the eco-stoichiometric ratio.

Calcium is an essential element for plants and animals. The quality of forage grasses, particularly their calcium content, is crucial for livestock nutrition. Meadow fescue (Festuca pratensis Huds.) is a major forage grass, but the nutrient contents of different varieties have not been extensively studied. In this study, we measured the calcium contents in the leaves of 105 varieties of meadow fescues under different conditions and in different stages of leaf development. We also examined water-soluble calcium, chelated calcium and calcium levels in cell wall components. We determined that No. 102 (from Bulgaria) is a high-calcium variety and that No. 88 (from the United States) is a low-calcium variety of meadow fescue. No. 102 had a higher calcium uptake rate than No. 88, but No. 102 also had a notably lower biomass than No. 88. Transcriptomic analysis identified 6288 upregulated genes and 12,249 downregulated genes in No. 102 compared to No. 88, with No. 88 having more upregulated genes related to calcium transport, signaling, aquaporin, β-galactosidase and β-glucosidase. These results suggest that a negative feedback mechanism and differences in carbohydrate accumulation contribute to the difference in calcium content between the two varieties. These findings should facilitate the production of superior forage to support the livestock industry.

Azospirillum brasilense is a nitrogen-fixing bacterium that lives in association with plant roots. These bacteria stimulate plant growth by stimulating the production of hormones such as auxins, gibberellins and cytokinins. The production of these compounds increases the density and length of root hairs, the emergence of lateral roots and the surface area of ​​the root system, which increases the possibility of nutrient absorption. This study aimed to evaluate the effect of different forms of inoculation of A. brasilense in oat and maize for forage production in a hydroponic system. A completely randomized experimental design was used, with four replications. Four treatments were used, consisting of: T1: Control; T2: application of A. brasilense on seed; T3: foliar application of A. brasilense; and T4: application of A. brasilense on seeds and foliar application. It was found that the application of the bacteria positively affects the growth of both species studied. However, application on seeds results in greater accumulation of dry mass in the roots, while foliar application or joint application results in greater development of the shoot and greater accumulation of fresh mass. Thus, it was concluded that the application of A. brasilense promotes plant growth through a combination of mechanisms, which results in a promising technique for obtaining higher yields in hydroponic green fodder cultivation.

Grasslands play a crucial role in supporting biodiversity and providing essential ecosystem services for both wildlife and human wellbeing. Despite their ecological and economic importance, the glaring knowledge gaps in scientific understanding of the Himalayan grasslands hamper their effective scientific management and also impede global synthesis under growing environmental change. To address this gap, we established three long-term ecological monitoring grassland sites in the Kashmir Himalaya and developed a standardized monitoring protocol for these ecosystems. The data generated so far from these sites revealed significant variations in vegetation composition, structure, biomass dynamics and nutrient (carbon and nitrogen) levels. Analysis of plant functional groups (PFGs), such as grasses, forbs and legumes, indicates marked differences among and between the sites. Notably, Dachigam National Park, located at a lower elevation, exhibits higher aboveground biomass and carbon storage compared to the higher-elevation sites, indicating a greater capacity to buffer against environmental changes. Aboveground and belowground biomass showed a strong negative relationship, with higher elevation sites showing relatively more belowground biomass compared to the low elevation site. Among functional groups, grasses dominated the low elevation site, while forbs and legumes formed a major component of aboveground biomass in high elevation sites. Continued monitoring of these variables over time will be pivotal to understanding how these grasslands might respond to a changing climate. The implications of this baseline data for developing the targeted conservation and management strategies for the Himalayan grassland ecosystems, and also for better allowing global knowledge synthesis, are discussed.

This study was designed to determine the forage capacity of some sweet sorghum (Sorghum bicolor var. saccharatum [L.] Mohlenbr.) genotypes under semi-arid climatic conditions. The experiment was set up in a randomized complete block design, with a total of 4 replications, in 2016 and 2017 under second crop conditions of the Harran plain (36° 54^′ 11.82^” N and 38° 55^′ 08.66^″ E), Sanliurfa, Turkey. A total of 21 sweet sorghum genotypes were used in the study. Significant differences were found between the genotypes for the traits that were tested (P ≤ 0.01). The average of two years' results demonstrated a range of values for dry matter yield and biomass yield, resulting in values ranging from 36.55 to 66.29 t/ha and 138.86 to 224.61 t/ha, respectively. The plant height exhibited a range of 333.6 to 418.8 cm, while the stem diameter demonstrated a variation of 22.58 to 25.85 mm. The dry matter content, stem proportion, leaf proportion and panicle proportion exhibited a range of 25.28 to 33.09%, 76.63 to 87.63%, 8.03 to 13.81% and 2.24 to 9.53%, respectively. Based on the tested characteristics, the genotypes UNL-Hybrid-3, Theis, Smith, M81-E, Corina, Ramada and Rio were found to be the most suitable for forage. According to the results of the correlation analysis, when high biomass and dry matter yield are targeted, taking into consideration genotypes with longer flowering and physiological maturation duration, taller and more leafy genotypes as selection criteria will increase the breeding success.

Although reducing seed shattering may improve the seed productivity of Italian ryegrass (Lolium multiflorum Lam.), information on genetic variation and improvement in this trait is limited. Therefore, we aimed to identify genetic variation in seed shattering in Italian ryegrass and evaluate its potential for breeding. Seed shattering was assessed by the percentage of shattered seeds, primarily after spike stripping. No significant differences in shattering were observed among five early-maturing varieties, whereas some variation was detected among five medium-maturing varieties, although the differences were not large. Plants within an extremely-early-maturing variety, ‘Minamiaoba’ (n = 36), and a medium-maturing variety, ‘Tachimusha’ (n = 95), exhibited considerable variation in seed shattering, ranging from 10.0% to 85.0% and 0.2% to 92.5%, respectively. The tensile strength of the non-basal florets accounted for the variation observed in ‘Minamiaoba’ genotypes. The correlations between seed shattering and total seed weight per spike (retained and shattered) were weak or non-significant, suggesting that reducing seed shattering could improve seed yield. In progeny derived from pair-crossed half-sibs of the reduced seed-shattering genotype, medium to high correlations (r = 0.46–0.79) for seed shattering were observed among different environmental conditions. Seed shattering in six progeny-parent combinations was also evaluated. The regression coefficients ranged from 0.79 to 0.95 when mean parental values were used as the explanatory variable and progeny values as the response variable, indicating high heritability. The observed wide genetic variation and high heritability suggest that genetic improvements to reduce seed shattering in Italian ryegrass may be relatively easy to achieve.

Rotation between rice (Oryza sativa) or corn (Zea mays) (summer) and forage crop (winter) is common in Southwest China. However, the impact of different ecological environments on phyllosphere bacterial communities and the factors influencing the survival and distribution of undesirable bacteria remain unclear. Therefore, we aimed to investigate the effects of cropland and cultivars on the abundance and diversity of phyllosphere bacteria in forage crops. Field experiments were conducted on croplands (dryland, DL; paddy field, PF) and three cultivars (forage pea, FP [Lathyrus sativus]; Italian ryegrass, IR [Lolium multiflorum]; smooth vetch, SV [Vicia villosa]). The results revealed 87 shared operational taxonomic units (OTUs) between the PF and DL bacterial communities, while FP, IR and SV shared 58 OTUs. Pantoea, Plesiomonas and Bryobacter were the three most abundant genera between the two cropland types. The relative abundances levels of Rahnella1, Aeromonas, Cetobacterium, Flavobacterium and Vibrio were significantly different among the three cultivars (p < 0.05). The physico-biochemical properties and microorganism numbers in SV and FP exhibited a high degree of overlap; however, they were distinct from those of IR (95% confidence interval). Physiological properties did not directly contribute to bacterial abundance but rather explained the differences in bacterial abundance among samples, likely by indirectly shaping the phyllosphere microenvironment. In summary, compared with PF, DL indirectly influenced microbial numbers indirectly by regulating leaf physiological properties, while both exhibited similar effects on bacterial diversity. Among the different forage crops, IR suppressed phyllosphere moisture and nutrient exchange owing to its lower stomatal density, resulting in a lower bacterial relative abundance than those of FP and SV. This finding elucidates bacterial community dynamics, particularly during the initial establishment phase of crop rotation systems, providing a valuable perspective for optimizing forage crop rotation strategies.