Thermopsis Lanceolata Research Articles

Variations in plant root traits shaped by intraspecific interactions are species-specific

Intraspecific plant interactions are crucial in terrestrial ecosystems, especially in artificially controlled ecosystems. Understanding plant root development can facilitate the manipulation of root traits to enhance the productivity and sustainability of agricultural and pastoral ecosystems. To date, most studies on interactions between the plants have focused on environmental factors or individual species; however, the lack of cross-species comparative analyses has resulted in a significant disparity in findings. In this study, we conducted a greenhouse experiment using five dominant species from alpine grasslands, including three legume species (Thermopsis lanceolata, Oxytropis ochrocephala, and Tibetia himalaica) and two grass species (Elymus nutans and Stipa aliena). Using single-plant cultivation as the control, we investigated the overall changes in plant biomass and root traits when two conspecific plants are grown together (intraspecifically). Simultaneously, we explored the differences in roots traits between the interaction and no-interaction zones. The results showed that, firstly, there was no significant difference in biomass and root traits of different zones when single-planted. But the impact of intraspecific interactions on neighboring plants exhibited significant species-specific. In terms of biomass and root traits (except for forks), E. nutans, T. lanceolata and T. himalaica responded significantly negatively to their neighbors. Whereas S. aliena and O. ochrocephala showed no significant changes and even positive responses. The overall trend of changes in the root zones, whether interactive or non-interactive, was consistent, either increasing or decreasing simultaneously, albeit to different extents. For instance, the difference between the interaction and no-interaction zones of T. lanceolata and O. ochrocephala was substantial, leading to allometric growth. Finally, our results showed poor correlations of physicochemical and nutrient factors with root traits in four of the five species, all except for E. nutans. Altogether, our findings confirmed that root trait variations resulting from intraspecific plant interactions are species-specific. These findings underscored the importance of species-specific in intraspecific plant interactions involving biological interactions among plants, which should be considered in future studies.

Effects of nitrogen addition and drought on the relationship between nitrogen- and water-use efficiency in a temperate grassland

BackgroundNitrogen- and water-use efficiency (NUE and WUE) reflect the capacity of plants to take up and utilize resources in the environments. Although N deposition and drought are known to affect plant growth and persistence, it remains elusive how plants adjust NUE, WUE and their relationship to adapt to the concurrent N deposition and drought under the context of global change. We conducted a field experiment in a temperate grassland in Inner Mongolia, in which N addition (10 g m–2 yr−1), drought (reduced 66% precipitation during growing season) and their combination were manipulated, and we explored the responses of both instantaneous (NUEINST and WUEINST) and long-term (NUELT and WUELT) WUE and NUE for six common plant species (Leymus chinensis, Stipa baicalensis, Thermopsis lanceolata, Potentilla bifurca, Thalictrum squarrosum, Klasea centauroide).ResultsAcross all the six species, NUEINST decreased and WUEINST increased with both N addition and drought; NUELT decreased with both N addition and drought, while WUELT decreased with N addition and increased with drought. A significant interactive effect between N addition and drought was detected, in that, drought weakened the negative effect of N addition on WUELT and NUELT, and N addition weakened the negative effect of drought on NUELT, but enhanced the positive effect of drought on WUELT. As a consequence, drought caused a trade-off between NUE and WUE, and N addition brought forth positive correlation between NUE and WUE. Meanwhile, the relationship between NUE and WUE varied among the species of different functional groups.ConclusionsOur study demonstrated that NUE, WUE and their relationship play an important role in determining their responses and adaptability to changes in soil nitrogen and water availability induced by N deposition and drought. Our results shed light on the antagonistic, synergetic and neutral effects between nitrogen deposition and drought on resource use efficiency, and further clarified the different adaptability among species of different functional groups, which will conduce to a comprehensive understanding on the role of NUE and WUE in plant persistence and coexistence in grassland ecosystems.

Separation and purification of quinolyridine alkaloids from seeds of Thermopsis lanceolata R. Br. by conventional and pH-zone-refining counter-current chromatography.

In this work, the preparative separation of quinolyridine alkaloids from seeds of T. lanceolata by conventional and pH-zone-refining counter-current chromatography. Traditional counter-current chromatography separation was performed by a flow-rate changing strategy with a solvent system of ethyl acetate-n-butanol-water (1:9:10, v/v) and 200mg sample loading. Meanwhile, the pH-zone-refining mode was adopted for separating 2.0g crude alkaloid extracts with the chloroform-methanol-water (4:3:3, v/v) solvent system using the stationary and mobile phases of 40mM hydrochloric acid and 10mM triethylamine. Finally, six compounds, including N-formylcytisine (two conformers) (1), N-acetycytisine (two conformers) (2), (-)-cytisine (3), 13-β-hydroxylthermopsine (4), N-methylcytisine (5), and thermopsine (6) were successfully obtained in the two counter-current chromatography modes with the purities over 96.5%. Moreover, we adopted nuclear magnetic resonance and mass spectrometry for structural characterization. Based on the obtained findings, the pH-zone-refining mode was the efficient method to separate quinolyridine alkaloids relative to the traditional mode.

Vegetation Types Variations to the South of Ngoring Lake from 2013 to 2020, Analyzed by Hyperspectral Imaging

Studying the variation in vegetation types within the source region of the Yellow River (SRYR) is of great significance for understanding the response of vegetation to climate change and human activities on the Qinghai-Tibet Plateau (QTP) permafrost. In order to understand the characteristics of the variation in vegetation associations in the SRYR under the influence of climate and human activities, two hyperspectral remote sensing images from HJ-1A in 2013 and OHS-3C in 2020 were used to extract the vegetation types located in the area south of Ngoring Lake, covering 437.11 km2 in Maduo County, from the perspective of vegetation associations. Here, the hybrid spectral CNN (HybridSN) model, which is dependent on both spatial and spectral information, was used for vegetation association classifications. On this basis, the variations in vegetation associations from 2013 to 2020 were studied using the transition matrix, and the variation in noxious weeds across different altitude and slope gradients was analyzed. As an example, Thermopsis lanceolata’s spatial distribution pattern and diffusion mechanism were analyzed. The results showed that (1) in addition to noxious weeds, herbage such as Poa poophagorum, Stipa purpurea, Kobresia humilis, and Carex moorcroftii increased, indicating that the overall ecological environment tended to improve, which may be attributed mainly to the development of a warm and humid climate. (2) Most of the noxious weeds were located at low altitudes with an area increase in the 4250–4400 m altitude range and a decrease in the 4400–4500 m altitude range. More attention should be given to the fact that the noxious weeds area increased from 2.88 km2 to 9.02 km2 between 2013 and 2020, which was much faster than that of herbage and may threaten local livestock development. (3) The Thermopsis lanceolate association characterized by an aggregated distribution tended to spread along roads, herdsmen sites, and degraded swamps, which were mainly affected by human activities and swamp degradation.

Exploring the anti‐α‐amylase activity of flavonoid aglycones in fabaceae plant extracts: a combined MALDI‐TOF‐MS and LC–MS/MS approach

SummaryA combination of TLC‐bioautography, MALDI‐TOF‐MS and LC–MS/MS methods was used to identify flavonoids with anti‐α‐amylase activity in extracts of Lathyrus pratensis L. (herb), L. polyphillus L. (fruits), Thermopsis lanceolata R. Br. (herb) and S. japonica L. (buds). After the TLC‐autobiography assay, substances with anti‐amylase activity were identified by MALDI‐TOF‐MS followed by confirmation of the result by LC–MS/MS. Results of the study revealed that the flavonoids apigenin, luteolin, formononetin, genistein and kaempferol display marked anti‐α‐amylase activity. Formononetin showed the largest activity. Compared with LC–MS/MS, MALDI‐TOF‐MS is a quick and convenient method; results can be obtained within minutes; and only minor sample amounts are required which allows us to analyse mixtures of substances without preliminary separation. However, the inability to distinguish between isomers is the main limitation of the method.

Determination of the Total Alkaloid Content of Thermopsis Dry Extract by HPTLC - Densitometry

When used to quantify alkaloids in thermopsis dry extract, acidimetric titration has several limitations, including insufficient specificity of the method and arbitrary selection of a titration endpoint. Different parts of the Thermopsis lanceolata plant produce alkaloids in different proportions: the herb is rich in thermopsine, whereas the seeds are rich in cytisine. Since thermopsine and cytisine have different pharmacological effects, it is important to identify and quantify individual alkaloids in thermopsis dry extract.The aim of the study was to develop and validate an analytical procedure for identifying and quantifying total alkaloids in thermopsis dry extract by high-performance thin-layer chromatography (HPTLC) with densitometric detection.Materials and methods. The study included samples from two pilot-scale batches of thermopsis dry extract and reference standards for cytisine and thermopsine. The authors used Merck HPTLС Silica Gel 60 F254 20×10 cm plates for chromatographic separation and analysed the results with a CAMAG® TLC Scanner 4 densitometer and the winCATS software.Results. The authors identified thermopsis dry extract using HPTLC separation followed by spectrodensitometry. The alkaloid-specific solution applied to chromatography plates helped to identify the three most abundant and four minor alkaloids of thermopsis. The most abundant alkaloids were thermopsine, cytisine, and an unidentified alkaloid with a retention factor of approximately 0.2. These three alkaloids accounted for almost 80% of the total alkaloid content of the dry extract. The authors quantified cytisine, thermopsine, and total alkaloids expressed as thermopsine.Conclusions. The authors developed and validated an analytical procedure for identifying and quantifying total alkaloids in thermopsis dry extract. This procedure offers the possibility of reducing the analysis time from 4–5 hours to 2–2.5 hours.

Synthesis, Properties and Spatial Structure of 4-[(3,5-Dimethyl-1,2-oxazol-4-yl)sulfonyl]cytisine

This article has studied the synthesis of a new derivative of the known alkaloid cytisine contained in the seeds of plants of Cytisus laburnum L. and Thermopsis lanceolata R.Br., both of the Lugiminosae family. The new compound has been obtained from two biologically active compounds, such as isoxazole and cytisine. It has been demonstrated that the reaction led to the single-stage method under very mild conditions to obtain 4-[(3,5-dimethyl-1,2-oxazol-4-yl)sulfonyl]cytisine. This class of compounds is promising for obtaining the new biologically active compounds. This article has examined, in detail, a structure with using the 1H and 13C NMR and two-dimensional NMR spectroscopy of COSY (1H-1H), HMQC (1H-13C) and HMBC (1H-13C). As a result, the homo- and heteronuclear spin-spin couplings should be established. The X-ray diffraction analysis has determined the spatial structure of a new derivative based on the cytisine alkaloid. Thus, its hemorheological activity has been studied.

Enhanced foliar 15 N enrichment with increasing nitrogen addition rates: Role of plant species and nitrogen compounds.

Determining the abundance of N isotope (δ15 N) in natural environments is a simple but powerful method for providing integrated information on the N cycling dynamics and status in an ecosystem under exogenous N inputs. However, whether the input of different N compounds could differently impact plant growth and their 15 N signatures remains unclear. Here, the response of 15 N signatures and growth of three dominant plants (Leymus chinensis, Carex duriuscula, and Thermopsis lanceolata) to the addition of three N compounds (NH4 HCO3 , urea, and NH4 NO3 ) at multiple N addition rates were assessed in a meadow steppe in Inner Mongolia. The three plants showed different initial foliar δ15 N values because of differences in their N acquisition strategies. Particularly, T. lanceolata (N2 -fixing species) showed significantly lower 15 N signatures than L. chinensis (associated with arbuscular mycorrhizal fungi [AMF]) and C. duriuscula (associated with AMF). Moreover, the foliar δ15 N of all three species increased with increasing N addition rates, with a sharp increase above an Naddition rate of ~10g N m-2 year-1 . Foliar δ15 N values were significantly higher when NH4 HCO3 and urea were added than when NH4 NO3 was added, suggesting that adding weakly acidifying N compounds could result in a more open N cycle. Overall, our results imply that assessing the N transformation processes in the context of increasing global Ndeposition necessitates the consideration of N deposition rates, forms of the deposited N compounds, and N utilization strategies of the co-existing plant species in the ecosystem.

The complete chloroplast genome of Thermopsis lanceolata: genome structure and its phylogenetic relationships within the family Fabaceae

Thermopsis lanceolata R. Br. belongs to the genus Thermopsis, Fabaceae. The alkaloids of T. lanceolata have anti-cancer, anti-heart rate disorders and other pharmacological effects. To explore the chloroplast genome of T. lanceolata and its phylogenetic relationship, a complete chloroplast genome of T. lanceolata was sequenced and annotated, and a phylogenetic tree was constructed. The complete chloroplast genome of T. lanceolata is a circular molecule of 151,526 bp, consisting of a large single copy (LSC) region of 83,780 bp, a small single copy (SSC) region of 15,566 bp, and a pair of inverted repeats (IRa and IRb) of 26,090 bp. The chloroplast genome of T. lanceolata contained 130 genes, including 85 protein-coding genes, 37 transfer RNA genes, and 8 ribosomal RNA genes. Phylogenetic analysis revealed a close relationship between T. lanceolata and T. turkestanica.

Maillard Reaction Products with Anti-Tobacco Mosaic Virus Activities Generated in Processed Thermopsis lanceolata R. Br. Seed Extract.

Six novel Maillard reaction products (MRPs) (1-6) were isolated from the processed Thermopsis lanceolata R. Br. seed extract, along with one biogenetically related intermediate (7). Compounds 1-4 possessed three rare dimerization patterns constructed by cytisine, whereas compounds 5 and 6 represented the first example of the addition products of cytisine and 5,6-dihydroxy-4-hexanolide. Their structures were elucidated by comprehensive spectroscopic data analysis and quantum chemistry calculations including GIAO 13C{1H} NMR and ECD calculation, combined with single-crystal X-ray diffraction analysis. Biologically, compound 3 displayed significant anti-tobacco mosaic virus activity compared with the positive control ningnanmycin.

Quinolizidine Alkaloids with Antitomato Spotted Wilt Virus and Insecticidal Activities from the Seeds of Thermopsis lanceolata R. Br.

As part of our ongoing investigation of pesticide active quinolizidine alkaloids (QAs) from the family Fabaceae, the chemical constituents of the seeds of Thermopsis lanceolata R. Br. were systematically investigated. Bioassay-guided fractionation and purification of the crude extract led to the isolation of seventeen new QAs (1-17), including three new naturally occurring compounds (15-17), along with 15 known compounds (18-32). Their structures were elucidated by comprehensive spectroscopic data analysis (IR, UV, NMR, and HRESIMS) and quantum chemistry calculations (13C NMR and ECD). The antitomato spotted wilt virus activities and insecticidal activities against Aphis fabae, Nilaparvata lugens (Stal), and Tetranychus urticae of compounds 1-32 were screened using the lesion counting method, spray method, and rice-stem dipping method, respectively. Biological tests indicated that compounds 6, 9, 10, and 18 displayed significant anti-TSWV activities compared with the positive control ningnanmycin. Compounds 3, 4, and 5 showed better insecticidal activities against A. fabae with LC50 values of 10.07, 12.07, and 6.56 mg/L, respectively. Moreover, compounds 5, 18, and 24 exhibited moderate insecticidal activities against N. lugens (Stal) with LC50 values of 37.91, 53.44, and 31.21 mg/L, respectively. Furthermore, compounds 9 and 10 exhibited moderate insecticidal activities against T. urticae.

Leaf Functional Traits of Two Species Affected by Nitrogen Addition Rate and Period Not Nitrogen Compound Type in a Meadow Grassland.

Plasticity of plant functional traits plays an important role in plant growth and survival under changing climate. However, knowledge about how leaf functional traits respond to the multi-level N addition rates, multiple N compound and duration of N application remains lacking. This study investigated the effects of 2-year and 7-year N addition on the leaf functional traits of Leymus chinensis and Thermopsis lanceolata in a meadow grassland. The results showed that the type of N compounds had no significant effect on leaf functional traits regardless of duration of N application. N addition significantly increased the leaf total N content (LN) and specific leaf area (SLA), and decreased the leaf total P content (LP) and leaf dry matter content (LDMC) of the two species. Compared with short-term N addition, long-term N addition increased LN, LP, SLA, and plant height, but decreased the LDMC. In addition, the traits of the two species were differentially responsive to N addition, LN and LP of T. lanceolata were consistently higher than those of L. chinensis. N addition would make L. chinensis and T. lanceolata tend to “quick investment-return” strategy. Our results provide more robust and comprehensive predictions of the effects of N deposition on leaf traits.

Predominant role of air warming in regulating litter decomposition in a Tibetan alpine meadow: A multi-factor global change experiment

Alpine ecosystems worldwide are experiencing multi-faceted climate changes, but the interactive effects of these drivers on litter decomposition are poorly understood. Here, we examined the effects of air warming, nitrogen (N) addition and altered precipitation, and their interactions on litter decomposition originating from four species (Elymus nutans, Kobresia capillifolia, Thermopsis lanceolata, Saussurea nigrescens) in a Tibetan alpine meadow. Among the three factors, air warming by open top chambers (OTCs) significantly decreased all litter decomposition except for K. capillifolia with the highest C:N ratio over one-year field decomposition. The reduced litter mass loss in the chambered plots was mainly attributed to OTC-induced decrease in soil temperature, with more negative effects of OTC on litter decomposition in winter and spring than in summer. However, N addition offset the negative effects of OTC on litter mass loss of K. capillifolia, likely by alleviating N limitation to this poor-quality litter decomposition. In addition, simulated precipitation increase promoted decomposition of high-quality litter (T. lanceolata and S. nigrescens) in the dry winter, likely by alleviating water stress. Together, our findings highlight the predominant role of climate in controlling litter decomposition in alpine ecosystems.

Thermlanseedlines A–G, seven thermopsine-based alkaloids with antiviral and insecticidal activities from the seeds of Thermopsis lanceolata R. Br.

Seven undescribed thermopsine-based alkaloids (1–7), including one undescribed biogenetically related intermediate (7), were isolated from the seeds of Thermopsis lanceolata R. Br. Compound 1 possessed a 6/6–6 tricyclic skeleton, while compounds 2–6 represented three rare dimerization patterns constructed by quinolizidine alkaloids. Their structures were elucidated by comprehensive spectroscopic data analysis as well as ECD calculations. Biologically, compound 6 displayed significant anti-Tomato spotted wilt virus (TSWV) activity compared with the positive control ningnanmycin. Moreover, compound 1 exhibited good insecticidal activity against Aphis fabae with LC50 value of 25.2 mg/L.

Two new cytisine-type alkaloids from the seeds of Thermopsis lanceolata

Two new (1 and 2) cytisine-type alkaloids that were chemically inseparable isomers (present in a 1:1 ratio) were identified from the seeds of Thermopsis lanceolata R. Br. Their structures were elucidated by comprehensive spectroscopic data analysis (IR, UV, NMR, HRESIMS) and ECD calculation. Compound 1 displayed significant anti-tobacco mosaic virus (TMV) activity, while compounds 1 and 2 displayed moderate insecticidal activities against Aphis fabae with LC50 value of 43.15 and 46.47 mg/L, respectively.

A new species of Micrurapteryx (Lepidoptera, Gracillariidae) feeding on Thermopsislanceolata (Fabaceae) in southern Siberia and its hymenopterous parasitoids.

A new species of leaf-mining moth described here as Micrurapteryxbaranchikovi Kirichenko, Akulov & Triberti, sp. nov. was detected in large numbers feeding on Thermopsislanceolata (Fabaceae) in the Republic of Khakassia (Russia) in 2020. A morphological diagnosis of adults, bionomics and DNA barcoding data of the new species are provided. The developmental stages (larva, pupa, adult), male and female genitalia, as well as the leaf mines and the infestation plot in Khakassia are illustrated; the pest status of the new species in the studied region is discussed. Additionally, parasitism rate was estimated, the parasitoid wasps reared from pupae of the new species were identified (morphologically and genetically) and illustrated . Among them, one ichneumonid, Campoplexsp. aff.borealis (Zetterstedt) and two braconids, Agathisfuscipennis (Zetterstedt) and Illidopssubversor (Tobias et Kotenko), are novel records for the Republic of Khakassia. Furthermore, they are all documented as parasitoids of Gracillariidae for the first time. The DNA barcode of A.fuscipennis is newly obtained and can be used as a reference sequence for species identification.

Insecticidal activity of twin compounds from podophyllotoxin and cytisine

To explore natural-product-based insecticide candidates, and high value-added application of natural plants in agriculture, a series of twin compounds were prepared from two natural products podophyllotoxin and cytisine, which are isolated from the plants Podophyllum hexandrum and Thermopsis lanceolata, respectively. Compounds IIa (X = Cl, Y = R1 = R2 = H), IIIc (X = Y = R1 = R2 = Cl) and IVd (X = R1 = R2 = Br, Y = H) exhibited >2-fold potent insecticidal activity of podophyllotoxin against armyworm with FMRs greater than 60%. SARs were also observed. It is noteworthy that the idea of twin insecticides was addressed for the first time. We hope this idea will be conducive to design new twin insecticidal agents, and lay the foundation for future high value-added application of the plants P. hexandrum and T. lanceolata as potentially botanical pesticides in agriculture.

Non-destructive identification of single hard seed via multispectral imaging analysis in six legume species

BackgroundPhysical dormancy (hard seed) occurs in most species of Leguminosae family and has great consequences not only for ecological adaptation but also for agricultural practice of these species. A rapid, nondestructive and on-site screening method to detect hard seed within species is fundamental important for maintaining seed vigor and germplasm storage as well as understanding seed adaptation to various environment. In this study, the potential of multispectral imaging with object-wise multivariate image analysis was evaluated as a way to identify hard and soft seeds in Acacia seyal, Galega orientulis, Glycyrrhiza glabra, Medicago sativa, Melilotus officinalis, and Thermopsis lanceolata. Principal component analysis (PCA), linear discrimination analysis (LDA), and support vector machines (SVM) methods were applied to classify hard and soft seeds according to their morphological features and spectral traits.ResultsThe performance of discrimination model via multispectral imaging analysis was varied with species. For M. officinalis, M. sativa, and G. orientulis, an excellent classification could be achieved in an independent validation data set. LDA model had the best calibration and validation abilities with the accuracy up to 90% for M. sativa. SVM got excellent seed discrimination results with classification accuracy of 91.67% and 87.5% for M. officinalis and G. orientulis, respectively. However, both LDA and SVM model failed to discriminate hard and soft seeds in A. seyal, G. glabra, and T. lanceolate.ConclusionsMultispectral imaging together with multivariate analysis could be a promising technique to identify single hard seed in some legume species with high efficiency. More legume species with physical dormancy need to be studied in future research to extend the use of multispectral imaging techniques.

The genetic diversity of microsymbionts from Thermopsis lanceolata growing in Mongolia

For the first time, bacteria were isolated and identified from the root nodules of a wild-growing medicinal legume plant Thermopsis lanceolata, originated from Mongolia. The taxonomic position of 14 isolates obtained was determined using of sequencing of the 16S rRNA (rrs) and atpD genes. It was shown a significant biodiversity of the isolates from T. lanceolata, which belonged to three genera of the order Rhizobiales: Phyllobacterium (family Phyllobacteriaceae), Rhizobium (family Rhizobiaceae) and Bosea (family Bradyrhizobiaceae). Six isolates belonged to the species Phyllobacterium zundukense and Phyllobacterium trifolii (100 и 99,9% rrs similarity with the type strains P. zundukense Tri-48T and P. trifolii PETP02T, respectivelly), three isolates were identified as Rhizobium anhuiense (99,8% rrs similarity with the type strain R. anhuiense CCBAU 23252T). Two slow-growing isolates of the genus Bosea Tla-534 and Tla-545 may potentially belong to new species, since their rrs-similarity to the closest type strains B. massiliensis LMG 26221T, B. lathyri LMG 26379T and B. vaviloviae Vaf18T was 98,5-99,0%. Non-rhizobial strains were not isolated. The isolation and future investigation of the rhizobial microsymbionts of the valuable medicinal legume Thermopsis lanceolata is one of the necessary prerequisites for its industrial cultivation.

Effects of grazing season and stocking rate on seed bank in sheep dung on the semiarid Loess Plateau

Endozoochorous dispersal of seeds by livestock has long attracted the attention of grassland scientists, but little is known about seed dispersal via Tan sheep dung on the dry grasslands of the Loess Plateau. We investigated the composition of dung seed bank of Tan sheep under summer and winter rotational grazing regimes at different stocking rates (2.7, 5.3 and 8.7sheepha–1), and assessed the relationships between seed mass and shape, egested seedling density and species richness and diversity. We also assessed the effects of stocking rate and grazing season on seedling density and species richness and diversity of the dung seed bank. Seeds of 10 pasture species germinated from Tan sheep dung with only two being annual species (Eragrostis pilosa and Chenopodium glaucum). The mean seed mass (±s.e.) was 2.59±0.23mg, ranging from 0.10mg (Cleistogenes songorica) to 10.59mg (Thermopsis lanceolata), and the mean seed shape index (±s.e.) was 0.10±0.02, ranging from 0.03 (Lespedeza bicolor) to 0.19 (Stipa bungeana). Species richness and diversity and seedling density decreased with increasing seed mass and shape index, suggesting that small, round seeds are most suitable for endozoochorous dispersal. Stocking rate had no effect on the number of germinated seeds that collected from summer or winter grazing pastures. Species richness and diversity and seedling density were greater in winter grazing pastures than in summer grazing pastures. Jaccard coefficients of similarity between the Tan sheep dung bank and aboveground vegetation were <0.5 for all stocking rates, indicating their weak relationship, but were significantly higher for winter than summer grazing. Plant seeds on the Loess Plateau could disperse through Tan sheep grazing, endozoochory can increase the heterogeneity of rotationally grazed plant communities, and this dispersal mode is an adaptation of plants to the harsh environment of the semiarid areas.