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通过研究川西亚高山/高山森林矿质土壤层微生物群落丰度和结构在季节性冻融期间的变化,可为深入认识亚高山/高山森林冬季土壤生态过程提供理论依据.于2009年8月至2010年8月,在植物生长季节、土壤冻结阶段(包括土壤冻结期和土壤深冻期)和土壤融化阶段(包括土壤融冻期和土壤融化后期),采用变性梯度凝胶电泳(PCR-DGGE)和实时定量PCR技术同步研究不同海拔冷杉次生林(3 023 m)、天然混交林(3 298 m)和岷江冷杉原始林(3 582 m)矿质土壤层微生物类群的变化特征.结果显示,随着土壤冻结的开始,土壤细菌数量显著降低(P<0.05),而在随后的融化过程中又显著升高;土壤真菌数量具有和细菌数量相似的变化趋势,在融化阶段显著升高;土壤古菌数量在土壤冻结阶段得到升高,表现出与细菌数量相反的变化趋势.并且,Shannon-Wiener指数(H)随森林类群的变化而变化,在土壤冻结阶段,细菌H主要表现为3 582 m处<3 298 m处<3 023 m处,古菌H表现为3 298 m处<3 023 m处<3582 m处,真菌H表现为3 023 m处<3 582 m处<3 298 m处;而在土壤融化阶段3种菌落的H均表现为3 582 m处<3 023m处<3 298 m处.综上,季节性冻融期间强烈的环境变化极大地影响了土壤微生物群落的数量和结构,但不同微生物类群在不同海拔表现出一定的差异.
By studying the change of abundance and structure of soil microbial communities in subalpine / alpine forest in western Sichuan during seasonal freezing and thawing period, this study may provide a theoretical basis for understanding the winter soil ecological processes in subalpine / alpine forest in depth. In August of this year, denaturing gradient gel electrophoresis (PCR-DGGE) was performed in the plant growth season, soil freezing stage (including soil freezing period and soil freezing period) and soil thawing stage (including soil thawing period and soil thawing period) (3 029 m), natural mixed forest (3 298 m), and Minjiang fir fir forest (3 582 m) were studied simultaneously with real-time quantitative PCR.The results showed that with the change of soil At the beginning of the freezing, the number of soil bacteria decreased significantly (P <0.05), and then increased significantly in the subsequent thawing process. The number of soil fungi showed a trend similar to that of bacteria and significantly increased in the thawing stage. The amount of archaeal soil And increased in the period of soil freezing, showing the opposite tendency with the number of bacteria.And Shannon-Wiener index (H) changed with the change of forest group, in the soil freezing stage, the fine The results showed that the fungi H mainly showed as 3 582 m <3 023 m <3 298 m, archaeal H 3 298 m <3 023 m <3582 m, and fungi H showed 3 023 m <3 582 m <3 298 m, while in the soil thawing stage, the H of the three colonies showed 3 582 m <3 023 m <3 298 m. In summary, the strong environmental changes during seasonal freeze-thaw cycles greatly affected The number and structure of soil microbial community, but different microbial populations at different altitudes showed some differences.