生物土壤结皮对土壤种子库的影响

Effects of Biological Soil Crusts on Seed Bank

在自然光照条件下,对草原化荒漠地带的苔藓与藻类两种生物土壤结皮进行干、湿处理,研究其上种子库组成与数量特征,结果表明:①有9种植物的幼苗出现在含有生物土壤结皮覆盖的表土中,它们分别是独行菜(Le-pidium ruderateL.)、油蒿(Artemisia ordosicaKrasch)、灰绿藜(Chenopodium glaucumL.)、多根葱(Allium poly-irhizumTurcz.ex Rgl.)、小画眉草(Rragrostis poaeoidesBeauv)、雾冰藜(Bassia dasyphylla(Fisch.et Mey))、马齿苋(Potulaca oleraceaL.)、狗尾草(Setaria viridis(L.))、苋菜(Amaranthus.retroflexusL.),其中一年生草本植物有7种;②在不同类型的结皮上,土壤种子库的总储量以及每种植物种子的储量存在着显著的差异:对于湿润处理的两种结皮,萌发的幼苗总密度存在着极显著的差异(P<0.001),对于干燥处理的两种结皮,萌发幼苗的总密度也存在着显著的差异(P<0.05);③水分是限制结皮种子库植物种子萌发的主要原因,苔藓与藻结皮上萌发的种子总密度都存在极显著的差异(P<0.001)。

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.