塔里木河下游土壤种子库分布格局及其与环境因子的关系

Spatial Distribution of Soil Seed Bank and Its Relation to Environmental Factors in Lower Reaches of Tarim River

在塔里木河下游选择20个样地,进行土壤种子库萌发试验,并应用典范对应分析(CCA)方法研究了该地区土壤种子库分布格局及其与环境因子的关系。结果表明,塔里木河下游土壤种子库中共有物种16种,分属于7科,并且以旱生耐盐物种为主,多数样地物种出现频次较低;种子库密度不高。CCA排序表明,地下水埋深、土壤含水量、电导、pH值和植被盖度等5个环境因子对土壤种子库分布格局有一定的影响。CCA第一排序轴与地下水位、地表植被盖度和土壤含水量关系显著,反应了水分因子的作用;CCA第二排序轴与土壤电导率关系显著,反映了盐分因子的作用。根据5个环境因子的特征,CCA排序可将土壤种子库中的16种植物分为4个组,对应于不同的环境变化梯度。

In order to analyze the spatial pattern of soil seed bank and its relation to environmental factors in the lower reaches of Tarim River, 20 sampling plots were established. Seedling germination experiment was carried out and ordination technique（canonical correspondence analysis） was used in the study areas. Results showed that there were 16 species, belonging to ？ families in soil seed bank, among which tolerant-drought and salinity species were dominant. Most species occurred infrequently and soil seed bank density was lower compared with other desert regions. Groundwater depth, soil moisture content, electric conductance, pH, vegetation coverage all influence the distribution of soil seed bank. The relationship among the first axe of the CCA, groundwater depth, standing vegetation coverage, and soil moisture content were significant, indicating the role of water availability factor. The relationship between the second axe of the CCA and the electric conductance was significant, indicating the role of salinity factor. Based on the above five environmental factors, 16 species of soil seed bank were divided into four groups.