原始红松林退化演替后土壤微生物功能多样性的变化

摘要

This study aimed to understand the changes of soil biotope and soil microbial functional diversity in the Lesser Khingan Mountain primitive Korean pine forest and subsequent succession by secondary forest.We selected soils of a typical primitive broad-leaved Korean pine forest and two main secondary forests (Betula platyphylla forest at the pioneer stage and a hardwood forest at the subclimax stage during degradation and succession of the forest vegetation) in Lesser Khingan Mountain as materials.We analyzed changing patterns of microbial functional diversity of the soils in the depths of 0-＜ 10 cm and 10-20 cm by using the Biolog-ECO microplate method.The results showed that the Average Well Color Development (AWCD) values increased with increasing incubation time;the values in the initial stage of incubation followed a decreasing order:broadleaved Korean pine ＞ hardwood forest ＞ B.platyphylla.In the terminal stage of incubation,the AWCD values of broadleaved Korean pine,B.platyphylla,and hardwood forest were 1.06,0.86 and 0.81,respectively,on 0-＜ 10 cm soil layers,and 0.68,0.47 and 0.45 on 10-20 cm soil layers.The higher AWCD value of the soil layers in the primitive forest indicated that the single carbon source metabolic activity of the soil microorganism in the primitive forest was significantly higher than that of the secondary forests.The AWCD values of 0-＜ 10 cm soil were significantly higher than that in 10-20 cm in the same kind of forest (P ＜ 0.05).Microbial diversity indices (Shannon-Wiener index,Simpson index,McIntosh index and Richness index) of the primitive forest were significantly higher than those of the secondary forests (P ＜ O.05).The results indicate that soil microbes in the primitive forest microbial had a higher utilization intensity to various carbon sources as compared with those in the secondary forests;the types of dominant carbon source utilized by soil microbial communities varied in different forest types.After degradation and subsequent succession of the primitive forest,soil microbial community during utilization of carbon sources was sensitive to the four carbon sources (e.g.,carbohydrates,amino acids,carboxylic acids and Polymer).%为了全面了解原始红松林退化演替为次生林后土壤生境及土壤微生物功能多样性的变化规律,以小兴安岭典型的原始阔叶红松林、退化演替后先锋阶段的白桦林及亚顶级阶段的硬阔叶林为研究对象,采用Biolog-ECO微平板检测法,分析三者0～＜ 10 cm和10 ～ 20 cm表层土的土壤微生物功能多样性变化规律.结果表明:各林型土壤微生物的AWCD值(平均颜色变化率)随培养时间的延长而增加,培养初期表现为原始阔叶红松林＞硬阔叶林＞白桦林;培养末期表现为原始阔叶红松林＞白桦林＞硬阔叶林,三者的AWCD值在0～＜10 cm土层分别为1.06、0.86、0.81,10～20 cm土层分别为0.68、0.47、0.45,原始林显著高于次生林(P＜0.05),说明原始林土壤微生物对单一碳源的代谢活性显著高于次生林;同一林型下土壤微生物的AWCD值均表现为O～＜10cm土层显著高于10 ～ 20 cm土层(P＜0.05).Shannon-Wiener多样性指数、Simpson指数、McIntosh指数和Richness丰富度指数也均表现为原始林显著高于次生林(P＜0.05).原始林土壤微生物对各类碳源的综合利用强度均大于次生林,不同林型下土壤微生物群落的优势碳源类型存在一定的差异,碳水类、氨基酸类、羧酸类和多聚物类碳源是原始林退化演替后土壤微生物群落在碳源利用上发生变化的敏感碳源.