不同海拔茶树根系土壤微生物群落多样性分析
Microbial community diversity in tea root zone soils at different elevations
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摘要: 从福建省泉州市安溪县不同海拔铁观音茶园采集了根系区域土壤, 利用磷脂脂肪酸(PLFAs)生物标记法研究了不同海拔茶园根系土壤微生物群落多样性。结果表明, 不同海拔茶树根系土壤共检测22个PLFAs, 不同的PLFAs在不同海拔茶树根系土壤分布差异明显, 可分为完全分布和不完全分布两种类型。高海拔(834 m)茶树根系土壤分布的PLFAs种类和数量都最多, 分布最高的前3个生物标记为16:0(指示细菌)、18:3ω6c(6,9,12)(指示真菌)、18:00(指示嗜热解氢杆菌)。对不同海拔茶树根系土壤特征微生物PLFAs分析表明, 代表细菌的16:0、代表真菌的18:3ω6c(6,9,12)和代表放线菌的10Me 16:0相对生物量在不同海拔茶树根系土壤中分布量不同, 细菌分布量最大, 其次是放线菌, 真菌分布量最小。微生物群落PLFAs标记聚类结果显示, 当欧氏距离为11.51时, 可将不同海拔茶园根系土壤的PLFAs生物标记分成3个大的类群, 类群I的PLFAs生物标记为完全分布且分布量中等, 类群Ⅱ的PLFAs生物标记为完全分布且分布量较高, 类群Ⅲ的PLFAs生物标记为不完全分布且分布量较低。分析多样性指数表明, Shannon-Wiener指数、Simpson指数和Pielou指数均是海拔834 m处最大, 海拔717 m处最低。Abstract: Soil samples were collected in tea root zone of Tieguanyin tea gardens at different elevations in Anxi County, Fujian Province. Then phospholipid fatty acids (PLFAs) biomarkers were used to analyze microbial community diversity in the tea root zone soils. Significant differences exist among the 22 PLFAs detected in the soil samples from 525 m, 603 m, 717 m and 834 m elevations. For the purpose of analysis, PLFAs biomarkers are divided into two groups — complete distribution group, which means that a biomarker is well distributed across soil sample; and incomplete distribution group, which means that a biomarker is distributed in a fraction of soil sample. Tea root zone soil at higher elevation exhibits richer PLFAs distribution both in type and amount. The PLFAs biomarkers with the first three maximum concentration are 16:0, 18:3ω6c(6, 9, 12) and 18:0 — respectively indicating bacteria, fungi and hydrogenobacter. Biomarker 16:0 has the richest distribution, followed by 10Me 16:0 (indicating actinomyces) and 18:3ω6c(6,9,12) at different elevations. Cluster analysis reveals that PLFAs in root zone soils at different elevations are categorized into three groups at an euclidean distance of 11.51. PLFAs biomarkers in the group one are completely distributive, but at medium contents at different elevations. PLFAs biomarkers in the group two are completely distributive at a much higher contens at different elevations than those in the group one. Contrary to the group two, PLFAs biomarkers in the group three are much less than in the group two, with an incompletely distributive characteristics. Based on community diversity indices of Shannon-Wiener, Simpson and Pielou, it is concluded that maximum Shannon-Wiener, Simpson and Pielou indices occur in root zone soils at 834 m elevation whereas the minimum in root zone soils at 717 m elevation.