新疆野生樱桃李天然林土壤种子库特征

采取野外调查、网筛分选和温室萌发相结合的方法，对新疆霍城县大西沟山区野生樱桃李天然林的土壤种子库物种组成、密度和生活史型、垂直空间分布、物种多样性及其与地上植被间关系进行了研究。结果表明：① 试验鉴定出的幼苗共有48种，隶属于19科，且一年生植物多达20种（41.7%），地下芽植物为15种（31.3%）；② 种子库中种子的数量自上而下呈先增加后减少的特征，有超过90%的种子分布在距地表5 cm以上的表层土壤及枯枝落叶层中，近90%的樱桃李种子分布在距地表2 cm以上的表层土壤及枯落层中；③ 土壤种子库中草本层物种的Margalef指数、Shannon-Wiener指数均为最高，其次为乔木层和灌木层，种子库物种多样性主要受草本层丰富度的影响；④ 野生樱桃李天然林土壤种子库与地上植被的相似性系数为0.315，表明地上植被对土壤种子库的贡献较大。但是，由于过度放牧，使得种子库的物种多样性在垂直空间上的分布规律受到干扰。

Soil Seed Bank under Natural Forest of Prunus divaricata in 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.