实验室条件下两种生物土壤结皮对荒漠植物种子萌发的影响

生物土壤结皮广泛分布在干旱、半干旱区，深刻影响着土壤表层特性，进而对植物种子散布、萌发和定居产生极大的影响。到目前为止，生物土壤结皮与植物关系的研究很少见到，并且这些有限的研究所得出的结论存在着争议。研究了不同年龄的两种生物土壤结皮（苔藓结皮和藻类结皮）对油蒿（Artemisia ordosica）和雾冰藜（Bassia dasyphylla）种子萌发的影响，同时也研究了这两种结皮在失去活性前后对油蒿、雾冰藜和小画眉草（Eragrostis poaeoides）种子萌发的影响。苔藓和藻类结皮的出现对油蒿和雾冰藜种子的萌发均有显著的促进作用，而结皮年龄对植物种子的萌发没有显著的差异。对于不同的植物种，结皮类型和活性对种子的萌发具有不同的作用。雾冰藜在两种结皮上的萌发有显著的差异而油蒿和小画眉草在两种结皮上的萌发没有显著差异。活藻类显著地增加了三种植物的种子萌发，活苔藓仅增加了油蒿和雾冰藜种子萌发量而对小画眉草种子的萌发没有作用，研究表明，生物土壤结皮对一些植物种子萌发具有明显的促进作用。

Effects of two types of biological soil crusts on the germination of desert vascular plants under laboratory conditions

Biological soil crusts are a universal and common feature of arid and semi-arid regions worldwide, and they greatly affect soil surface properties which may alter seed dispersal, germination and establishment of vascular plants. Few studies have examined the effects of biological soil crusts on vascular plants, and conclusions from these have been variable. In this study, we investigated the effects of two types of biological soil crusts (moss crust and algae crust) of five different ages on seed germination of two vascular plants, and the effects of crust condition (living crust and dead crust) on seed germination of three vascular plants. Biological soil crusts 18, 24, 41 and 49 years old from areas where the vegetation had been replanted were compared with 100 years old crusts from an area of natural vegetation. The presence of both algae and moss crusts significantly enhanced the germination of Bassia dasyphylla and Artemisia ordosica compared with surfaces from which the crusts had been removed. For both Bassia dasyphylla and Artemisia ordosica, there was no significant effect of crust age on germination on either moss crust or algae crust. The effects of crust type and crust condition on seed germination were variable and species-specific. Crust type significantly influenced germination of Bassia dasyphylla but not Artemisia ordosica and Eragrostis poaeoides. Living algae crust significantly increased germination of Artemisia ordosica, Eragrostis poaeoides and Bassia dasyphylla compared with dead crusts and uncrusted soil, while living moss crust enhanced the germination of both Artemisia ordosica and Bassia dasyphylla but not Eragrostis poaeoides. Our study indicates that biological soil crusts can have marked effects on the germination of some plant species.