固沙植被区生物土壤结皮中蓝藻群落的多样性

采用非培养法对腾格里沙漠沙坡头固沙植被区的蓝藻多样性进行了研究,通过蓝藻通用引物PCR扩增其16S rDNA序列并构建16S rDNA文库,对阳性克隆进行测序、比对分析和构建系统发育树,同时通过Shannon-Weaver多样性指数、Chao和ACE丰富度指数及Simpson优势度指数对蓝藻多样性进行比较分析。结果表明:腾格里沙漠沙坡头地区蓝藻可分为5大类:颤藻目(Oscillatoriales,64.55%),色球藻目(Chroococcales,1.82%),念珠藻目(Nostocales,16.36%),宽球藻目(Pleurocapsales,6.82%)和未分类蓝藻(10.45%)。人工固沙植被区经过57年的恢复,蓝藻群落Chao和ACE丰富度指数均明显小于天然植被区(恢复逾100年),而且其群落结构与天然植被区仍然存在着统计学显著差异的区别,说明荒漠区生态系统微生物多样性的恢复是一个长期的过程。

Cyanobacterial Diversity in Biological Soil Crusts of Sand-fixing Vegetation Regions

The cyanobacterial diversity in Shapotou region of Tengger desert was investigated through a culture-independent approach by constructing cyanobacterial specific 16S rDNA clone libraries. Positive clones selected randomly were sequenced and analyzed for phylogenetic tree constructing. Several diversity index including Shannon-Weaver diversity index, Simpson index, Chao and ACE richness index were done to estimate differences of cyanobacterial community between two regions. The results showed that the cyanobacterial community of Shapotou region of Tengger desert consists of Oscillatoriales(64.55%), Chroococcales(1.82%), Nostocales(16.36%), Pleurocapsales(6.82%) and unclassified Cyanobacteria(10.45%). After 57 years of restoration, Chao and ACE richness index of cyanobacterial community in artificial sand-fixing vegetation region were distinctively smaller than those of the natural vegetation region(recovering for more than 100 years), and there are still statistically significant difference in cyanobacterial community structure between the artificial sand-fixing vegetation region and natural sand-fixing vegetation region, which indicates the restoration of microbial diversity of desert ecosystem is a very long process.