Soil Seed Bank under Natural Forest of Prunus divaricatain Xinjiang,China

Field survey and laboratory observation and experiment were conducted to study the characteristics of soil seed bank under natural forest of Prunus divaricata in Huocheng County,Xinjiang,China,and also the composition and vertical distribution of soil seed bank under litter layer,life form of vegetative,biodiversity and similarity between aboveground vegetation soil seed bank.The results were as follows:(1) Forty-eight species in 19 families were identified from the soil seed bank through germination test in laboratory.In the species of soil seed bank,20 species were therophytes,they were dominant and occupied 41.7% of the total species in soil seed bank,and 15 species were geophytes and accounted for 31.3% of the total;(2) Density of seeds in soil seed bank was increased at first,and then decreased rapidly with the increase of soil depth,more than 90% seeds were in litter layer and soil horizon of 0-5 cm in depth,and about 90% seeds of P.divaricata were in litter layer and soil horizon of 0-2 cm in depth;(3) The species diversity in different layers of soil seed bank was that the Margalef index and Shannon-Wiener index of species were the highest in herb layer,they were decreased in arbor and shrub layers,and the species diversity was mainly affected by species richness in herb layer;(4) Sorensen similarity coefficient between the vegetation and soil seed bank was 0.315,which revealed that the contribution of aboveground vegetation to soil seed bank was high.The conclusions above revealed that the biodiversity and its vertical distribution were strongly affected by grazing disturbance.