选取青藏高原东北缘地区自然降水梯度下土壤样品,利用磷脂脂肪酸(PLFA)技术研究了土壤微生物群落结构随年平均降水量变化情况,探讨引起微生物群落结构变化的主要因子。结果表明:随着年平均降水量的下降,土壤有机碳和全氮含量显著下降。细菌、真菌和放线菌含量随着年降水量的下降而显著减少,但在干旱区生物量有增加趋势,表明干旱地区少量的降水不会引起微生物量的显著改变。经相关分析与典范对应分析,在0~5 cm和5~10 cm土层,年降水量与土壤主要理化性质、土壤微生物量有着显著的相关关系,表明在干旱半干旱地区年降水量是影响土壤微生物群落结构的主要因子,并且在0~5 cm土层更加显著。
Soil microbial response to climate change will affect the whole ecological process,and represent many uncertainties feedback of ecosystem to climate change. Six sample sites and two soil depths (0-5 cm,5-10 cm),a total of twelve samples were collected along a mean annual precipitation (MAP) gradient in arid and semi-arid,northeastern of Tibetan Plateau and PLFA technology was used to analyze microbial community structure and total microbial biomass. These results showed that total organic carbon and total nitrogen were significantly declined with the MAP decreasing,which was also found in bacteria,fungi,actinomycete biomass. However,microbial biomass had an increased trend in the extreme arid area. Person correlation analysis and Canonical Correspondence Analysis showed that both in 0-5 cm and 5-10 cm soil depth,MAP had a significant correlation with soil physicochemical properties and soil microbial biomass indicate that MAP was a key factor in soil microbial community structure in arid and semi-arid area,which was more significant in 0-5 cm soil depth. The study will provide theoretical basis for further studies of soil microorganisms' response to the water landscape change in the background of global climate change in arid zone.
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