Effects Of Stimulated Precipitation On Charateristic Of Seed Germination And Seedling Of Soil Seed Bank In Seriphidium Transiliense Desert In Xinjiang

Seriphidium transiliense desert is important grassland for grazing in spring and autumn in Xinjiang,which was severely degraded and expected to restoration and treatment,soil seed bank plays an important role in the degraded grassland vegetation for update,succession and restoration.The climate in Xinjiang will be"warm and wet"in the future,so we studied moderated degradation Seriphidiumtransiliense desert under different stimulated precipitation:control(CK),increased by 5%(W5),increased by 10%(W10),increased by 10%(W15),increased by 20%(W20),increased by 25%(W25)to the 0-5cm,5-10 cm soil layer,seed germination dynamic,the species composition,the density of germination,the characteristics of established seedling community,plant diversity,and the similarity analysis between soil seed germination and the above-ground vegetation,we expected to provide a reference for the restoration of the desert grassland under the climate change.The main results were as follows:(1)With the stimulated precipitation,species of soil seed germination and total density of germination increased in 0-5cm of S.transiliense desert soil seed bank compared with CK(6 species,248.4 grain/m²),in stimulated precipitation of 20%,25%,soil seed germination of species significantly increased 1.5 times,2.3imes,total density of germination increased160%,248%,5-10cm soil layer appeared the same trendency.For germination species,stimulated precipitation significantly promoted the germination of Geranium transversal,Taraxacum monochlamydeum,Kochia prostrate,with the increase of precipitation,the soil seed germination of S.transiliense desert increased gradually,coefficient of similarity was up to 0.88.(2)Stimulated precipitation was benefited to the germination and establishment for S.transiliense desert soil seed bank,with the increasing of precipitation,the height,coverage,density,biomass of community plant increased in different degree,W25 was the highest,and compared with CK,those characteristics of 0-5cm(5-10cm)respectively increased by 150%(79%),79%(140%),400%(146%),146%(201%),and 0-5 cm was better than 5-10 cm in response of the stimulated precipitation.With the increasing of precipitation,for the main species:the height,coverage,density,biomass of population for Petrosimonia sibirica,Ceratocarpu sarenarius,G.transversal,S.transiliense was increased,and S.transiliense as the edifacator would increase significantly.With the increase of precipitation,the similarity between the establishment seedling communities and the above-ground vegetation increased gradually and the coefficient of similarity reached 0.58.(3)With the increasing of precipitation,the Shannon-Wiener,Pielou and Patrick of both germination number and establishment seedlings appeared increased tendency in S.transiliense desert soil seed bank,5-10cm appeared similar situation.(4)In short,stimulated precipitation promoted the germination number of S.transiliense desert soil seed bank and the quantity of seedling establishment,improved the germination of species,increased its similarity with the above-ground vegetation,which was benefited to the succession and recovery of degraded grassland.