摘要:高纬度多年冻土区是全球变化的敏感区域，揭示不同雪被覆盖条件下土壤微生物群落结构的演变规律，对于预测寒区森林生态系统对全球变化的响应具有重要意义。以大兴安岭多年冻土区白桦次生林为研究对象，采用磷脂脂肪酸法（PLFA）对比分析自然积雪和遮雪处理土壤微生物群落结构的动态变化特征。结果表明：土壤总磷脂脂肪酸含量在植被生长季初期最高，积雪稳定期最低，其中含量较高的PLFA为18：2ω6，9c、a15：0、i16：0、17：1ω8c、18：1ω9c和16：1ω5c，不同时期各优势PLFA含量存在一定差异。遮雪显著降低积雪稳定期细菌PLFA含量、增加真菌PLFA含量（P<0.05），但对其他时期土壤微生物群落结构和多样性均未产生显著影响。冗余分析（RDA）表明，土壤总磷脂脂肪酸、真菌、真菌/细菌和革兰氏阴性菌与土壤含水量、pH和铵态氮均呈显著正相关，细菌和革兰氏阳性菌受土壤总磷、总氮和硝态氮影响较大。



Abstract:The high latitude permafrost regions are sensitive to global climate change. Revealing the change regularity of soil microbial community structure under different snow cover conditions is of great significance to predict the response of cold region forest ecosystem to global climate change. We took Betula platyphylla secondary forest in permafrost region of Great Hing'an Mountains as the research object. The dynamic change characteristics of soil microbial community structure treated with natural snow cover and snow shade were compared and analyzed by using phospholipid fatty acid method (PLFA). The results showed that the total PLFA content of soil was the highest at the initial stage of vegetation growth and the lowest at the stage of snow stabilization. Of which the higher PLFA content were 18:2ω6,9c, a15:0, i16:0, 17:1ω8c, 18:1ω9c and 16:1ω5c, and the prevalent PLFA content varied in different periods. The snow shade significantly reduced the bacterial PLFA content and increased the fungi PLFA content at the stage of snow stabilization (P<0.05), but it had no significant effect on soil microbial community structure and diversity in other periods. The redundancy analysis showed that the total PLFA content of soil, fungi, fungi/bacteria, and gram-negative bacterial were significantly positively correlated with soil water content, pH and NH₄-N, whereas bacteria and gram-positive bacterial were significantly influenced by total phosphorus, total nitrogen and NO₃-N of soil.





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