中亚热带地区两种森林植被类型土壤微生物群落结构

利用磷脂脂肪酸(PLFA)生物标记法分析了中亚热带地区罗浮栲天然林和相邻的杉木人工林土壤微生物群落结构特点.结果表明: 两种植被类型的磷脂脂肪酸总量、细菌特征脂肪酸、真菌特征脂肪酸、放线菌特征脂肪酸、革兰氏阳性菌和革兰氏阴性菌特征脂肪酸含量均为0～10 cm高于10～20 cm土层，罗浮栲天然林高于杉木人工林.在两种植被类型的两个土层中，细菌PLFAs含量均显著高于真菌PLFAs含量.两种植被类型中，细菌PLFAs含量约占PLFAs总量的44%～52%，而真菌仅占6%～8%，表明细菌在该地区两种植被类型土壤中处于优势地位.主成分分析表明，土壤微生物群落结构差异主要由植被类型差异引起，土层深度的影响相对较小.相关分析显示，革兰氏阴性菌、革兰氏阳性菌以及细菌的PLFAs含量与pH呈显著负相关，与含水量呈显著正相关；土壤微生物主要类群PLFAs含量与总氮、有机碳、C/N和铵态氮均呈显著正相关.

Soil microbial community structure of two types of forests in the mid-subtropics of China.

Soil microbial community structures were analyzed by biomarker method of phospholipid fatty acid (PLFA) for a natural forest dominated by Castanopsis fabri (CF) and an adjacent plantation of Cunninghamia lanceolata (CL) in the mid subtropics of China. The results showed that the amounts of total PLFAs, bacterial PLFAs, fungal PLFAs, gram positive bacterial PLFAs and gram negative bacterial PLFAs in the 0-10 cm soil layer were higher than in the 10-20 cm soil layer, and each type of PLFAs in CF were higher than in CL. In either soil layer of the two forest types, the contents of bacterial PLFAs were significantly higher than those of fungal PLFAs. In the two
forests, the contents of bacterial PLFAs accounted for 44%-52% of total PLFAs, while the contents of fungal PLFAs just accounted for 6%-8%, indicating the bacteria were dominant in the soils of the two vegetation types. Principal component analysis showed that the influence of vegetation types was greater than soil depth on the microbial community structures. Correlation analysis showed that gram negative bacterial PLFAs, gram positive bacterial PLFAs and bacterial PLFAs were significantly negatively correlated with pH, positively with water content, and the PLFAs of main soil microorganism groups were significantly positively correlated with soil total nitrogen, organic carbon, C/N and ammonium.