关键词: 增水, 伊犁绢蒿荒漠, 土壤种子库, 萌发密度, 群落相似性

Abstract: This study explored the adaptation mechanisms for seed germination of Seriphidium transiliense desert soil seed banks under six different precipitation treatments -CK, increased 5% (W₅), increased 10% (W₁₀), increased 15% (W₁₅), increased 20% (W₂₀) and increased 25% (W₂₅). The response of species composition, seed germination dynamics and density were measured at 0-5 cm and 5-10 cm layers, and the Sorensen similarity coefficient between the soil seed banks and aboveground vegetation was also analyzed. The results showed that species number and total germination density in the 0-5 cm layer increased with rising precipitation levels. Compared with CK (3 species, 146.5 grain·m^-2), the number of germination species in the 0-5 cm layer increased by 3.7 times in W₂₀ and 4.3 times in W₂₅, while total seed germination density increased by 65.2% and 195.6% respectively and on average total germination quantities occupied 2.8% of the soil seed bank (7.2×10³ grain·m^-2). Seed germination in the 5-10 cm layer changed at the same rate as the 0-5 cm layer, with total germination seed quantities occupying 6.2% of the storage bank (1.2×10³ grain·m^-2). Increased precipitation improved the germination density of Geranium transversale, Kochia prostrate and Taraxacum monochlamydeum. Sorensen similarity between the soil seed bank and aboveground vegetation also increased with rising precipitation, with the highest coefficient being 0.81. In summary, increased precipitation stimulated germination density in the S. transiliense desert soil seed bank, increased the number of germination species and the similarity coefficient between the soil seed bank and aboveground vegetation, all of which benefit the succession and restoration of degraded grassland.

Key words: increased precipitation, Seriphidium transiliense desert grassland, soil seed bank, germination density, similarity of community