引用本文:郑裕雄,曹际玲,杨智杰,林成芳,杨玉盛.氮沉降对亚热带常绿阔叶天然林不同季节土壤微生物群落结构的影响[J].土壤学报,2018,55(6):1534-1544.
ZHENG Yuxiong,CAO Jiling,YANG Zhijie,LIN Chengfang,YANG Yusheng.Impacts of Nitrogen Deposition on Soil Microbial Community Structure in Subtropical Natural Evergreen Broad-leaved Forest Relative to Season[J].Acta Pedologica Sinica,2018,55(6):1534-1544
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氮沉降对亚热带常绿阔叶天然林不同季节土壤微生物群落结构的影响
郑裕雄,曹际玲,杨智杰,林成芳,杨玉盛
福建师范大学湿润亚热带山地生态国家重点实验室培育基地,福建师范大学地理科学学院,福建师范大学湿润亚热带山地生态国家重点实验室培育基地,福建师范大学地理科学学院,福建师范大学湿润亚热带山地生态国家重点实验室培育基地,福建师范大学地理科学学院,福建师范大学湿润亚热带山地生态国家重点实验室培育基地,福建师范大学地理科学学院,福建师范大学湿润亚热带山地生态国家重点实验室培育基地,福建师范大学地理科学学院
摘要:
以亚热带地区细柄阿丁枫( Altingia gracilipes)天然林为研究对象,开展2年(2010—2011年)的原位模拟大气氮沉降试验,设置3个氮水平(以氮(N)含量计算):对照(CK, 0 kg·hm-2·a-1)、低氮(LN, 50 kg·hm-2·a-1)、高氮(HN,100 kg·hm-2·a-1)。采用磷脂脂肪酸(PLFA)技术探讨常绿阔叶天然林土壤微生物群落结构对氮沉降的响应。结果表明,天然林土壤微生物以细菌为优势类群,占微生物总PLFA含量的78.3%。夏季土壤微生物群落结构与其他季节发生显著差异;LN仅显著改变夏季土壤微生物群落结构;HN导致春季和冬季土壤微生物群落结构发生显著分异,且在不同季节对土壤微生物变化类群的影响不同。此外,氮沉降未使真菌与细菌比(F:B)和革兰氏阳性菌与革兰氏阴性菌比(G+:G-)发生显著改变,而使不同结构的环丙烷脂肪酸或异构脂肪酸等特殊脂肪酸比值发生改变,这表明短期氮沉降虽然改变了土壤微生物的群落结构,但并未影响微生物对环境变化的响应力,微生物可能通过改变特殊脂肪酸含量应对短期氮沉降,不同季节的应对策略有一定差异。因此,在探讨氮沉降对亚热带地区森林生态系统土壤微生物群落结构的影响时有必要考虑季节因素。
关键词:  细柄阿丁枫天然林  氮沉降  磷脂脂肪酸(PLFA)  微生物群落结构  季节动态
DOI:10.11766/trxb201804210081
分类号:
基金项目:国家自然科学基金项目(31670623, 31770663)资助
Impacts of Nitrogen Deposition on Soil Microbial Community Structure in Subtropical Natural Evergreen Broad-leaved Forest Relative to Season
ZHENG Yuxiong,CAO Jiling,YANG Zhijie,LIN Chengfang and YANG Yusheng
State Key Laboratory for Subtropical Mountain Ecology of the Ministry of Science and Technology and Fujian Province, School of Geographical Sciences, Fujian Normal University,State Key Laboratory for Subtropical Mountain Ecology of the Ministry of Science and Technology and Fujian Province, School of Geographical Sciences, Fujian Normal University,State Key Laboratory for Subtropical Mountain Ecology of the Ministry of Science and Technology and Fujian Province, School of Geographical Sciences, Fujian Normal University,State Key Laboratory for Subtropical Mountain Ecology of the Ministry of Science and Technology and Fujian Province, School of Geographical Sciences, Fujian Normal University,State Key Laboratory for Subtropical Mountain Ecology of the Ministry of Science and Technology and Fujian Province, School of Geographical Sciences, Fujian Normal University
Abstract:
【Objective】Soil microbes are the drivers of material circulation and energy flow in ecosystems, and their community structures may be used to characterize responses of soil ecological processes to environmental changes. This study was conducted in a natural Altingia gracilipes forest in the subtropical area and lasted for two consecutive years. This study was oriented to explore impacts of nitrogen (N) deposition on the dynamics of soil microbes, 【Method】 An in-situ N deposition simulation experiment was designed to have three treatments, i.e. CK (0 kg·hm-2·a-1), LN (50 kg·hm-2·a-1) and HN (100 kg· hm-2·a-1) in N deposition level, was carried out in 2010—2011, and the technique of phospholipid fatty acids (PLFAs) was used to explore diversity and composition of the soil microbial community.【Result】Results show that the soil microbial community in the forest consisted mainly of bacteria, gram-positive bacteria, gram-negative bacteria, fungi and actinomycetes. Among them, bacteria were the dominant fraction, contributing 78.3% to the total microbial PLFAs content. Significant differences were found between treatments and seasons in soil microbial community structure. Treatment LN had its soil microbial community structure altered significantly only in summer, when increased abundances were observed of bacterial, Gram-positive, Gram-negative and fungal residual PLFA markers but not i17:0, a17:0, 18:1ω7c, and 18:1ω7t markers. Treatment HN varied with the season, too, in soil microbial community structure. Decreased abundances of 16:1ω7c, 16:1ω7t, 18:1ω7t, and cy17:0 markers were found in spring, and of 18:1ω9 and 18:2ω6,9c markers in winter. In addition, no significant change was found in ratio of fungi to bacteria and of Gram-positive bacteria to Gram-negative bacteria in either Treatment LN or HN, but a significant one was in content of special fatty acids, such as cyclopropane fatty acid or isomeric fatty acid. Treatment LN increased the ratio of cyclopropane fatty acids to Precursor fatty acids all the year around, and also the ratio of isomeric fatty acids to anti-isomeric fatty acids in winter and spring, while Treatment HN increased the ratio of isomeric fatty acids to anti isomeric fatty acids in summer and autumn, but did not affect much the ratio of cyclopropane fatty acids to Precursor fatty acids throughout the entire experimental period. So the effects of N deposition on soil microorganisms do vary with seasons. Therefore, it is necessary to take season into consideration when the impacts of N deposition on soil microbial community structure in the subtropical forest ecosystem are studied. 【Conclusion】All the findings in this experiment demonstrate that short-term N deposition changes the soil microbial community structure, but not the ability of the soil microorganisms responding to environmental changes. Soil microbes respond to short-term N deposition through changing the content of special fatty acids, however, the response varies with the season. Comprehensive analysis shows that the change in soil microbial community structure is not only affected by soil substrate availability, but also soil temperature, moisture and other environmental factors that varies with the season. So they may serve as important factors affecting changes in soil microbial community structure in the subtropical evergreen broad-leaved forest. All the findings in this study may serve as reference for exploration of the mechanism of soil microbes affecting soil nutrient cycling in the subtropical natural forest as affected by nitrogen deposition in future. As the experiment was quite short in time, it is quite possible for soil microorganisms to get adapted to long-term nitrogen deposition. Therefore, in the context of steady increase of nitrogen deposition in the future, a long-term field experiment on nitrogen deposition should be carried out using high-resolution molecular biology methods, for better understanding of the mechanisms of soil microorganisms responding and adapting to nitrogen deposition in subtropical forest ecosystems.
Key words:   Altingia gracilipes forest  Nitrogen deposition  Phospholipid fatty acid (PLFA)  Soil microbial community structure  Seasonal dynamics