Abstract: Seed germination and seedling growth and survival are important for successful settlement of plants, which are often affected by biotic and abiotic environments. Plant-soil feedback is a new concept in which plants affect soil properties through soil organic matter turnover and rhizosphere effect, and such changes in soil properties in turn affect the growth and settlement of this species or other species and plant community composition. It plays an important role in understanding species settlement and vegetation restoration. In this study, we conducted an indoor pot experiment to examine the plant-soil feedbacks across four dominant herbaceous species common in the early restoration and succession of subalpine forests in Southwest China. The characteristics of seed germination and seedling growth of plants in soil at different succession stages were explored, aiming to provide theoretical basis for scientific guidance in restoring the initial community species pairing and improving grassland productivity. The results showed that the seed germination rate of Anemone rivularis in native soil was significantly higher than that in Poa poophagorum soil, which may be related to its high utilization rate of soil nitrate nitrogen and the high relative abundance of Burkholderiaceae bacteria. A negative feedback was found on the growth of Poa poophagorum seedlings and Koeleria macrantha seedlings in the soil of Anemone rivularis and Potentilla fragarioides. There were abundant Mortierellaceae fungi in the soil of Anemone rivularis and Potentilla fragarioides, which can promote plant growth by accelerating litter decomposition and regulating rhizosphere bacterial community. A negative feedback was found on the growth of Koeleria macrantha, Anemone rivularis, and Potentilla fragarioides seedlings in the Poa poophagorum regulated soil. Soil organic carbon and nitrate nitrogen could indirectly regulate bacterial and fungal communities, thus promoting seedling biomass. Our results indicated that herbaceous seedlings were more prone to negative feedback than seeds. Soil organic carbon, available nitrogen, and soil microorganisms could directly or indirectly regulate the settlement of herbaceous species.

Key words: plant-soil feedback, seed germination, seedling, biomass, bacteria, fungi