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采用变性梯度凝胶电泳技术(DGGE),分析土壤细菌16SrDNA和土壤真菌28SrDNA特异性片段多态性,研究了不同发育阶段杉木人工林对土壤微生物群落结构的影响。结果表明:土壤微生物群落结构随着杉木人工林的发育年龄而改变,杉木人工林土壤微生物群落多样性和丰富度随杉木生长发育显著增加(P<0.05),但均显著低于次生阔叶林(P<0.05);聚类分析表明,不同发育阶段杉木人工林土壤真菌群落相似性均<60%,而土壤细菌群落相似性最高可达65%,由此可推测不同发育阶段杉木人工林土壤真菌群落结构变化较土壤细菌群落结构变化剧烈;相关性分析表明,不同发育阶段杉木人工林土壤速效氮、碳氮比与土壤微生物群落多样性显著相关(P<0.05)。本研究表明,长期种植单一杉木人工林能够通过改变土壤理化性质来影响土壤微生物群落组成,进而影响森林生态系统养分循环,导致人工林林分生产力下降。
Using denaturing gradient gel electrophoresis (DGGE), 16SrDNA of soil bacteria and 28SrDNA specific fragments of soil fungi were analyzed. The effects of Cunninghamia lanceolata plantations on soil microbial community structure were studied. The results showed that the structure of soil microbial community changed with the age of Chinese fir plantation. The diversity and abundance of soil microbial community in Chinese fir plantation increased significantly with the growth and development of Chinese fir (P <0.05) (P <0.05). The results of cluster analysis showed that the similarities of soil fungi community in Cunninghamia lanceolata plantations at different developmental stages were all less than 60%, while the similarity of soil bacterial communities was up to 65%. Therefore, it could be inferred that Cunninghamia lanceolata plantation The results showed that soil available nitrogen and C / N ratio were significantly correlated with soil microbial community diversity (P <0.05). This study shows that long-term planting of single fir plantations can affect soil microbial community composition by changing the soil physical and chemical properties, thereby affecting nutrient cycling in forest ecosystems, resulting in decreased plantation productivity.