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Effects of Elymus nutans extract on growth of highland grasses. Values are mean ± SD (n = 5). Different letters denote significant differences between treatments with a > b > c > d
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Elymus nutans has been widely planted together with other perennial grasses for rebuilding degraded alpine meadow atop the Qinghai-Tibetan Plateau. However, the rebuilt sown pastures begin to decline a few years after establishing. One of the possible causes for the degradation of sown grassland may come from allelopathy of planted grasses. The pur...
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... Previous studies have mainly focused on autotoxicity in high-quality forage crops such as Medicago sativa (Nakahisa et al. 1993;Ghimire et al. 2019) and other herbaceous species like Kochia scoparia, Plantago lanceolate, Medicago truncatula, and Scutellaria baicalensis, etc. (Newman and Rovira 1975;Zhang et al. 2010;Wang et al. 2022a). Allelopathy has also been documented in invasive species such as Solidago canadensis (Wang et al. 2018b), Mikania micrantha (Wu et al. 2015), and Centaurea stoebe (Thorpe et al. 2009), weed control species such as Artemisia argyi (Chen et al. 2022), grassland degeneration indicators such as Artemisia frigida (Li et al. 2010;Zuo et al. 2011;Zhang et al. 2012;Wang et al. 2022b), Potentilla acaulis , and Stellera chamaejasme (Wang et al. 2022b), and grassland degradation restoration species such as Elymus nutans (Quan et al. 2021). Despite these findings, the allelopathic potential of many common grassland plants remains unknown. ...
... In addition, several studies have documented that the response of test plants to allelochemicals follows a concentration-dependent inhibition pattern (Omezzine and Haouala 2013;Chen et al. 2017;Quan et al. 2021), others reported a "low-concentration promotion and high-concentration inhibition" pattern, which simply means the "hormesis effect" (Rudrappa et al. 2007;Chon and Nelson 2010;Chen et al. 2017;Wang et al. 2018c, b;Liu et al. 2022b). For example, studies have shown that Medicago truncatula and alfafa inhibit seed germination and seedling growth at concentrations ranging from 0.002 to 0.01 g mL −1 (Wang et al. 2022a). ...
... The absolute value of RI represents the intensity of the effect, with a maximum value of 1. The synthetical effect (SE) is often used to express the strength of the allelopathic effect and refers to the arithmetic mean of the RI of each test item under the same treatment (Wang et al. 2021(Wang et al. , 2022bQuan et al. 2021). In this study, SE was calculated as (RI GR + RI RL + RI SL ) / 3, where RL and SL represent root length and shoot length, respectively. ...
Allelopathy has a profound impact on the germination and growth of plants, influencing the establishment of plant populations and shaping community ecological patterns. However, the allelopathic potential of many grassland species remains poorly understood. In this study, we prepared aqueous extracts from 17 herbaceous plants to investigate their allelopathic effects on the seed germination and seedling growth of Leymus chinensis, a dominant grassland species. Our results revealed that the response of L. chinensis to allelopathic compounds was dependent on the specific plant species, extract concentration, and target plant organ. Notably, Fabaceae plants exhibited a stronger allelopathic potential than Poaceae, Asteraceae, and other plant families. Moreover, we observed that root growth of L. chinensis was more sensitive to allelopathy than shoot growth, and seed germination was more affected than seedling growth. Generally, the germination of L. chinensis was strongly inhibited as the donor plant extract concentration increased. The leachate of Fabaceae plants inhibited the seedling growth of L. chinensis at concentrations ranging from 0.025 to 0.1 g mL⁻¹. On the other hand, the leachate from other families’ plants exhibited either inhibitory or hormetic effects on the early growth of L. chinensis, promoting growth at 0.025 g mL⁻¹ and hindering it at concentrations between 0.05 and 0.1 g mL⁻¹. These findings highlight the significant allelopathic potential of grassland plants, which plays a critical role in establishing plant populations and associated ecological processes. In addition, they shed light on the coexistence of other plants with dominant plants in the community.
... Elymus sinosubmuticus S.L. Chen (Els) and E. tangutorum (Nevski) Hand.-Mazz. (Elt) were grown by Tongde Feed Fruits Production in Qinghai Province, China (35°15′N, 100°38′E), which is located in the eastern part of the Qinghai-Tibet Plateau [27]. The soil pH in this area is about 7-8, and the soil background value of cadmium is less than 0.2 mg L −1 (Environmental Quality Standard for Soils of China, GB15618-1995). ...
Cadmium (Cd) pollution is a global environmental problem. It is of great significance to find a kind of pasture that can grow normally in a cadmium environment, especially in the Tibetan Plateau. We studied the fruit germination and fruit growth of Elymus sinsubmuticus S.L. Chen and Elymus tangutorum (Nevski), native plants of the Tibetan Plateau, in different cadmium environments. The results showed that with increased cadmium stress, the fruit germination rate, final germination rate, fruit-vigor, average germination time, and germination-speed index for the two grass species gradually decreased, and the 50% germination time for the seed gradually increased. Root length, biomass, and the number of leaves decreased in both species. We quantified the fruit germination and growth of plants in the cadmium environment and found that E. sinosubmuticus S.L. Chen had better fruit germination and fruit growth, and it had the development potential of cadmium pollution control.
... A mixture of diverse forage species is considered as another option to experimentally prove effectiveness in improving forage productivity [65,66]. Directly, some highly allelopathy-tolerant forage seeds can be used as a subsequent alternative for restoring sparse natural grassland caused by allelopathy [67]. Additionally, the pattern of mixing species also has another benefit for pastures. ...
Plants can produce and release allelochemicals to interfere with the establishment and growth of conspecific and interspecific plants. Such allelopathy is an important mediator among plant species in natural and managed ecosystems. This review focuses on allelopathy and alle-lochemicals in grasslands and forests. Allelopathy drives plant invasion, exacerbates grassland degradation and contributes to natural forest regeneration. Furthermore, autotoxicity (intraspecific allelopathy) frequently occurs in pastures and tree plantations. Various specialized metabolites, including phenolics, terpenoids and nitrogen-containing compounds from herbaceous and woody species are responsible for allelopathy in grasslands and forests. Terpenoids with a diversity of metabolites are qualitative allelochemicals occurring in annual grasslands, while phenolics with a few specialized metabolites are quantitative allelochemicals occurring in perennial forests. Importantly, allelochemicals mediate below-ground ecological interactions and plant-soil feedback, subsequently affecting the biodiversity, productivity and sustainability of grasslands and forests. Interestingly, allelopathic plants can discriminate the identity of neighbors via signaling chemicals, adjusting the production of allelochemicals. Therefore, allelochemicals and signaling chemicals synergistically interact to regulate interspecific and intraspecific interactions in grasslands and forests. Allelopathy and allelochemicals in grasslands and forests have provided fascinating insights into plant-plant interactions and their consequences for biodiversity, productivity and sustainability, contributing to our understanding of terrestrial ecosystems and global changes.
... Elymus nutans (Elymus nutans Griseb.) is a perennial gramineous grass that grows in alpine regions . It is highly resistant to drought, cold, and salt, and has become a preferred forage species for planting in high altitude areas (Tan et al., 2020;Quan et al., 2021). As the forage livestock industry expands at high altitudes, the areas of cultivated grasslands growing E. nutans will continue to increase; therefore, the stability of E. nutans swards in alpine regions needs to be addressed. ...
The majority of terrestrial plants can form symbiotic associations on their roots with arbuscular mycorrhizal fungi (AMF) in the soil to stimulate the growth and nutrient uptake of the host plant and to improve plant resistance to insects and disease. However, the use of AMF for insect control on gramineous forages requires further study. Here, we evaluated the effects of AMF (Funneliformis mosseae) inoculation on the defense against Locusta migratoria attack in Elymus nutans. Inoculation assays showed that mycorrhizal plants had a higher resistance than non-inoculated plants, as evidenced by plants having more plant biomass, a higher nitrogen and phosphorus content, and greater lipoxygenase (LOX) activity. The results of insect damage showed that in addition to a decrease in the enzyme phenylalanine-ammonia-lyase, the activities of other plant defense-related enzymes (including polyphenol oxidase and β-1,3-glucanase) were increased. A key enzyme, LOX, belonging to the jasmonic acid (JA) signaling pathway was notably increased in mycorrhizal treatment. Volatile organic compounds (VOCs) were identified using gas chromatography mass spectrometry and the results showed that several metabolites with insect-resistant properties, including D-Limonene, p-Xylene, 1,3-Diethylbenzene were detected in mycorrhizal plants. These findings suggest that mycorrhizal inoculation has potential applications in insect management on forage grasses and demonstrates that the JA signaling pathway is essential for insect resistance in Elymus nutans.
... Each receptor type may respond differently to donor extracts [49,50]. L. sativa is sensitive to allelopathic effects and is a model recipient plant in allelopathy bioassay studies [34,43,44]. ...
Allelopathy is an important process in plant communities. The effects of allelopathy on seed germination and seedling development have been extensively investigated. However, the influences of extract soaking time and concentration on the foregoing parameters are poorly understood. Here, we conducted a seed germination assay to determine the allelopathic effects of the donor herbs Achnatherum splendens (Trin.) Nevski, Artemisia frigida Willd., and Stellera chamaejasme L., from a degraded grassland ecosystem in northern China, on lettuce (Lactuca sativa L.) seed germination and early seedling growth. Extract soaking times (12 h or 24 h) did not exhibit significantly different effects on lettuce seed germination or seedling development. However, all aqueous herb extracts inhibited lettuce seed germination and root length (RI < 0) and promoted lettuce shoot length, stem length, leaf length, and leaf width (RI > 0) at both low (0.005 g mL−1) and high (0.05 g mL−1) concentrations. Moreover, A. splendens extracts increased seedling biomass (RI > 0) and synthetical allelopathic effect (SE > 0) at both concentrations. In contrast, both A. frigida and S. chamaejasme extracts had hormesis effects, which stimulate at low concentrations (RI > 0) but inhibit at high concentrations (RI < 0) on seedling biomass and synthetical allelopathic effect (SE). The results suggest that allelopathic potential may be an important mechanism driving the dominance of A. frigida and S. chamaejasme in degraded grasslands. Reseeding allelopathy-promoting species such as A. splendens may be beneficial to grassland restoration. The present study also demonstrated that seedling biomass, root and shoot length, and seed germination rate are the optimal bioindicators in allelopathy assays and could be more representative when they are combined with the results of multivariate analyses.
Elymus nutans Griseb. is an important herbage for forage and ecological restoration in the Qinghai‐Tibet Plateau (QTP). It is widely distributed in different habitats of the QTP and has been reported to have high genetic diversity in protein, morphology and DNA sequence. The main objective of our investigation has been to obtain some knowledge of E. nutans chromosome genetic diversity. In this study, the TE probe S5 and tandem repeat probe AAG combined with sequential GISH were able to successfully distinguish different subgenomes and chromosomes in 7 E. nutans accessions from major global distribution sites. On this basis, a total of 123 individuals from four representative populations of E. nutans in the QTP were hybridised. The results of the experiment showed that four types of reciprocal translocations between subgenomes were observed in the four wild populations, and the translocation chromosomes, frequency, and heterozygosis were different in each population. The distribution and quantity of S5 and AAG signals also varied within and among the four populations. The results indicated that E. nutans had high genetic diversity at the chromosome level both within and among populations, and it was speculated that non‐homologous recombination was one of the reasons for the high genetic diversity. These results provide important theoretical guidance for the collection, protection, and evaluation of E. nutans .
Elymus sibiricus is a highly valuable perennial forage that is widely planted in the Qinghai-Tibet Plateau (QTP) region. However, E. sibiricus artificial grasslands have a short utilization lifespan, and reach the highest yield in the 2nd and 3rd year of plantation, then rapidly drop its productivity. We hypothesized that autotoxicity is one of the mechanisms for the reduction of the productivity. To test this hypothesis, we prepared the water extract from rhizosphere soils of E. sibiricus planted for 3, 4, 5, and 8 years and examined the effects of the extract concentrations at 0.05, 0.1, 0.2, and 0.5 g/mL on seed germination, seedling growth, physiological characteristics and phytohormones in the aboveground and roots of E. sibiricus . The results showed that the soil extract concentration, planting years, and their interaction had significant influences on the most of these indices. The soil extract inhibited the seed germination and growth of seedlings, and the inhibitory effects appeared to be stronger at the 0.5 g/mL rhizosphere soil extract for 5 and 8 years. The superoxide dismultase and peroxide activities, the free proline concentration, soluble sugar concentration were altered. The malondialdehyde concentration was, in general, increased, especially in 8 years soil extract. The indole acetic acid and gibberellic acids concentrations were lowered, while the abscisic acid concentration varied. These changes were depending on the extract concentration and the years of planting, without clear patterns in some of them in response to the extract concentration and planting years. In summary, autotoxicity can be a contributor to the retardation of the growth and development of artificial E. sibiricus grasslands. The inhibitory effects could be attribute to impaired antioxidant capacity and disturbance of osmortic-regulatory substances and plant hormones, and are more profound on the root than on the aboveground part of the seedlings.
