冻融循环对金川泥炭沼泽土壤微生物量及群落结构的影响  

Effect of freezing and thawing on soil microbial biomass and community structure in Jinchuan peatlands

作　　者：孙嘉鸿 郭彤 董彦民 王升忠 汪祖丞[1,2,3,4] 徐志伟 SUN Jiahong;GUO Tong;DONG Yanmin;WANG Shengzhong;WANG Zucheng;XU Zhiwei(Key Laboratory of Geographical Processes and Ecological Security of Changbai Mountains,Ministry of Education,School of Geographical Sciences,Northeast Normal University,Changchun 130024,China;Institute for Peat and Mire Research,Northeast Normal University,Changchun 130024,China;Jilin Provincial Key Laboratory for Wetland Ecological Processes and Environmental Change in the Changbai Mountains,Northeast Normal University,Changchun 130024,China;Key Laboratory of Wetland Ecology and Vegetation Restoration of National Environmental Protection,Northeast Normal University,Changchun 130024,China)

机构地区：[1]东北师范大学地理科学学院,长白山地理过程与生态安全教育部重点实验室,长春130024 [2]东北师范大学泥炭沼泽研究所,长春130024 [3]东北师范大学长白山湿地与生态吉林省联合重点实验室,长春130024 [4]东北师范大学国家环境保护湿地生态与植被恢复重点实验室,长春130024

出　　处：《生态学报》2022年第7期2763-2773,共11页Acta Ecologica Sinica

基　　金：国家自然科学基金项目(32071599);中央高校基本科研业务费(2412019FZ001);国家重点研发计划项目(2016YFC0500407)。

摘　　要：冻融作用显著改变土壤微生物活性及碳氮循环过程。以长白山金川泥炭沼泽0—15 cm和15—30 cm土壤为研究对象,进行室内冻融交替模拟实验。实验设置两个冻融幅度(-10—10℃和-5—5℃)。经过0/1/3/5/7/15次冻融循环后,分别采用氯仿熏蒸法和磷脂脂肪酸法测定泥炭沼泽土壤微生物量及磷脂脂肪酸含量,并与未进行冻融处理的FTC(0)对比。实验结果表明:冻融作用对土壤微生物量碳、氮及微生物磷脂脂肪酸含量有显著影响(P<0.001)。15次冻融交替作用后,土壤微生物碳(MBC)含量均显著增加,土壤微生物量氮(MBN)含量显著降低。两种冻融模式下,各类型微生物磷脂脂肪酸含量均显著降低。冻融作用显著改变了泥炭沼泽土壤微生物群落结构。冻融作用降低了土壤真菌/细菌比值(-5—5℃,0—15 cm土壤除外),增加了革兰氏阳性菌/革兰氏阴性菌比值。-5—5℃冻融作用下,各土壤微生物磷脂脂肪酸含量变幅大于-10—10℃,土壤MBC的变化则与其相反,在-10—10℃变化幅度更大。两种冻融幅度下MBC与大部分微生物群落在15—30 cm土壤的变幅更大,这说明冻融作用对不同深度土壤微生物量和微生物群落结构的影响存在差异。冻融次数对土壤微生物量和各类型磷脂脂肪酸含量有显著影响(P<0.01)。相关性分析结果表明多种微生物磷脂脂肪酸含量与MBN含量呈正相关关系(P<0.01),与DOC含量呈负相关关系(P<0.05)。综上,冻结作用促进了微生物的死亡,为融化期微生物生存提供更多碳源与营养物质,改变了土壤微生物群落结构。冻融期间各类型微生物磷脂脂肪酸含量降低,可能会降低泥炭沼泽土壤碳汇能力。Freezing and thawing cycles(FTCs) significantly changed the soil microbial activity and carbon and nitrogen cycling processes. A laboratory freezing-thawing stimulating experiment was conducted using 0—15 cm and 15—30 cm soil samples from Jinchuan peatland in Changbai Mountain. Two FTC amplitudes, namely,-10—10 ℃ and-5—5℃, were tested. Soil microbial biomass and phospholipid fatty acid(PLFA) concentrations were analyzed using chloroform fumigation method and phospholipid fatty acid method, respectively. Soil properties were analyzed after 0, 1, 3, 5, 7, and 15 cycles and compared with the properties of FTC(0). Results showed that freezing-thawing cycle had significant effects on soil microbial biomass carbon(MBC), microbial biomass nitrogen(MBN), and microbial phospholipid fatty acids(P<0.001). Soil microbial biomass carbon(MBC) increased significantly, but soil microbial biomass nitrogen(MBN) decreased compared with the FTC(0) after 15 FTCs. All groups of PLFAs concentrations dramatically decreased both in the-5—5 ℃ and-10—10 ℃ FTC amplitudes. The Freezing and thawing cycles significantly changed the soil microbial community structure with soil Fungi/Bacteria ratio decreasing(except-5—5 ℃, 0—15 cm soil) but Gram-positive bacteria/Gram-negative bacteria ratio increasing after FTCs. The effect of FTCs on soil microbial PLFAs under FTC amplitude of-5—5 ℃ was greater than that under the FTC amplitude of-10—10 ℃, but the opposite phenomenon was observed with respect to the effect of FTCs on MBC. The effect of FTCs on soil MBC and most groups of PLFAs were greater in the 15—30 cm than those in the 0—15 cm under the two FTC amplitudes. This indicated that the effect of FTCs on soil microbial biomass and microbial community varied with soil depth. The number of FTCs had a significant influence on soil microbial biomass and PLFAs(P<0.05). The results of correlation analysis showed that the different group of soil microbial PLFAs were positively correlated with the soil MBN concentrat

关 键 词：冻融循环 室内模拟实验 泥炭沼泽 磷脂脂肪酸 土壤有机碳、氮 

分 类 号：S154.3[农业科学—土壤学]