• 关键词：季节性冻融  扎龙湿地  微生物群落  胞外酶  磷脂脂肪酸

• 基金项目：国家自然科学基金（No.41501065）；中国博士后科学基金项目（No.2017M611381）；黑龙江省普通本科高等学校青年创新人才培养计划项目（No.UNPYSCT-2017177）；黑龙江省博士后资助经费项目（No.LBH-Z17100）

• 陈泓硕
• 哈尔滨师范大学地理科学学院, 哈尔滨 150025

• 马大龙
• 哈尔滨师范大学地理科学学院, 哈尔滨 150025

• 姜雪薇
• 哈尔滨师范大学地理科学学院, 哈尔滨 150025

• 刘梦洋
• 哈尔滨师范大学地理科学学院, 哈尔滨 150025

• 臧淑英
• 哈尔滨师范大学地理科学学院, 哈尔滨 150025

• 摘要：选取扎龙湿地芦苇沼泽为研究对象，采用磷脂脂肪酸法和微孔板法研究了季节性冻融期土壤微生物群落结构和胞外酶活性的动态变化规律.结果表明，微生物总磷脂脂肪酸（PLFA）含量和细菌PLFA含量均呈先降低后升高趋势，而真菌PLFA含量呈先升高后降低趋势.冻融初期至融冻初期，β-葡萄糖苷酶显著降低了71.84%，β-N-乙酰氨基葡萄糖苷酶表现为先升高后降低趋势，酸性磷酸酶在融冻初期最高、冻融初期最低，过氧化物酶和多酚氧化酶峰值均出现在融冻后期.主成分分析表明，季节性冻融显著改变了土壤微生物群落结构.冗余分析发现，土壤含水率与总PLFA、细菌、革兰氏阳性菌、革兰氏阴性菌、放线菌、过氧化物酶和多酚氧化酶呈显著正相关（p<0.05）；土壤全磷、速效磷、速效氮与真菌和β-N-乙酰氨基葡萄糖苷酶呈显著正相关；β-葡萄糖苷酶主要受土壤碳氮比和有机质影响，而土壤微生物与胞外酶活性在不同冻融时期具有显著相关性（p<0.05）.因此，探究全球变化背景下土壤微生物和胞外酶对季节性冻融过程的响应机制，可为深入解析扎龙湿地土壤质量演变特征及湿地生态系统功能的恢复与保护提供科学依据.

• Abstract：The dynamics change regulations of microbial community structure and extracellular enzymes activity of reed swamp in Zhalong wetland were studied by using phospholipid fatty acid and microplate method. The results showed that microbial total phospholipid fatty acid(PLFA) content and bacterial PLFA content represented a trend of decreasing first and then increasing, while fungal PLFA content represented a trend of increasing first and then decreasing. From the early freezing-thawing stage to the early thawing stage, β-glucosidase decreased by 71.84%, and β-N-acetyl-glucosaminidase increased first and then decreased; the acid phosphatase was the highest in the early stage of thawing and the lowest in the early stage of freezing and thawing; the peak values of peroxidase and polyphenol oxidase appeared in the late stage of thawing. Principal component analyses (PCA) showed that seasonal freezing and thawing significantly changed soil microbial community structure. Redundancy analyses (RDA) found that soil moisture content was positively correlated with total PLFA, bacteria, Gram-positive bacteria, Gram-negative bacteria, actinomycetes, peroxidase and polyphenol oxidase (p<0.05); soil total phosphorus, available phosphorus and available nitrogen were positively correlated with fungi and β-N-acetylglucosaminidase; β-glucosidase was mainly affected by soil carbon to nitrogen ratio and organic matter, but soil microbes were significantly correlated with extracellular enzyme activies in different freeze-thaw periods (p<0.05). Therefore, exploring the response mechanism of soil microbes and extracellular enzymes to seasonal freezing and thawing processes under the background of global change can provide a scientific basis for further analysis of the soil quality evolution characteristics of Zhalong wetland and the restoration and protection of wetland ecosystem functions.

• Key words：seasonal freeze-thaw  Zhalong wetland  microbial community  extracellular enzymes  phospholipid fatty acids

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