Effects of Biological Soil Crusts on Seed Bank
生物土壤结皮对土壤种子库的影响

Experiments on sorts and densities of seeds in different biological soil crusts were conducted in natural illumination.The experiment was arranged in four treatments: moss crust in dry and moist condition,algae crust in dry and moist condition.The result indicates that:(1)there are nine kinds of seeds germinated in the two sorts of crusts,they are Artemisia ordosica Krasch Chenopodium glaucum L,Allium polyirhizum Turcz.ex Rgl.,Rragrostis poaeoides Beauv,Amaranthus.retroflexus L.,Potulaca oleracea L,Setaria viridis(L.),Bassia dasyphylla (Fisch.et Mey)respectively,among them,seven kind of plants are the annual;(2) the differences of seeds number in different crusts are significant: in moist crusts,there is an extremely significant difference(P<0.001),in dry crust,there is a significant difference(P<0.05);(3)from the different water content in crusts,and the difference of germinated seeds(P<0.001),we can conclude that water content in crusts is the main restriction to numbers of germinated seeds.