生态系统生境改变对土壤微生物群落结构的影响

Effects of Ecosystem Habitat Changes on the Response of Microbial Community Structure

    摘要
  • 摘要:
      目的  森林和农田生态系统的土壤有机碳和微生物群落结构存在显著差异，为了预测生态系统对不断变化的环境条件的瞬时响应，需明确土壤微生物群落结构对生境气候变化的响应。
      方法  在我国北方地区同一纬度的森林和农田生态系统中设置土柱置换试验，对生物标识物磷脂脂肪酸和土壤因子进行分析，探究土柱置换两年后土壤微生物群落结构对生境改变的响应并明确影响微生物群落结构的主要土壤因子。
      结果  ①森林土壤置换到农田生境后，上层土壤微生物生物量显著降低（P < 0.05）。其中总微生物生物量下降了28.2%，细菌生物量下降了27.9%，真菌生物量下降了44.1%，革兰氏阴性菌生物量下降了39.6%，革兰氏阳性菌生物量下降了18.8%，放线菌生物量下降了19.8%；置换的下层土壤中仅革兰氏阴性菌生物量显著降低（P < 0.05）。②农田土壤置换到森林生境后，上层土壤各类群微生物生物量呈增加趋势，但差异不显著；而下层放线菌生物量和总微生物生物量显著下降（P < 0.05）。③土壤微生物群落结构变化均与土壤因子显著相关，其中土壤含水率对微生物群落结构变化的贡献率可占到27.5% ~ 50.9%。
      结论  整体来说，农田生境对森林土壤微生物的影响强度要大于森林生境对农田土壤微生物群落结构的影响。土壤含水率是生境改变后影响土壤微生物群落结构变化的主要因子。

     

    Abstract:
      Objective  There exists significant differences in soil organic carbon and microbial community structure between forest and cropland ecosystems. It is possible to clarify the response of soil microbial communities to changes in habitat climate in order to predict the transient response of ecosystems to changing environmental conditions.
      Method  Soil translocation experiments were set up between forest and cropland ecosystems in the the northern of China. The study explored the microbial community structure after cropland soil translocated to forest ecosystem and forest soil translocated to cropland ecosystem for two years using biomarker-phospholipid fatty acids, and analyzed the edaphic factors for to investigate the relationships between the alteration of microbial community structure and edaphic factors under changed climate habitats in forest and cropland ecosystems.
      Result  ① The biomass of all microbial groups in the topsoil decreased significantly after the forest soil translocated to the cropland ecosystem (P < 0.05). Specially, the total microbial biomass, bacterial biomass, fungal biomass, gram-negative bacterial biomass, gram-positive bacterial biomass and actinomycete biomass decreased 28.2%, 27.9%, 44.1%, 39.6%, 18.8% and 19.8% respectively. In the subsoil, only gram-negative bacterial biomass significantly reduced (P < 0.05). ② For the cropland soil translocated to the forest ecosystem, general increased in the biomass of all microbial groups at the topsoil, significantly decreased in total microbial and actinomycete biomass at subsoil (P < 0.05). ③The redundancy analysis showed that there was a significant correlation between the changes in soil microbial communisty structure and edaphic factors. The contribution of soil moisture to microbial community structure was from 27.5% to 50.9%.
      Conclusion  Overall, the effect of cropland environment on forest soil microorganisms is more stronger than the influence of forest ecosystem on cropland microbial community structure. Soil moisture is the predominated to influence soil microbial community structure.

     

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