引用本文:陈法霖,张 凯,向 丹,吴爱平,李有志,邹冬生,郑 华.桉树凋落物对土壤微生物群落的影响: 基于控制实验研究[J].土壤学报,2019,56(2):432-442.
CHEN Falin,ZHANG Kai,XIANG Dan,WU Aiping,LI Youzhi,ZOU Dongsheng,ZHENG Hua.Impacts of Litter Decomposition of Eucalyptus on Soil Microbial Community:A Microcosm Study[J].Acta Pedologica Sinica,2019,56(2):432-442
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桉树凋落物对土壤微生物群落的影响: 基于控制实验研究
陈法霖1, 张 凯2, 向 丹3, 吴爱平1, 李有志1, 邹冬生1, 郑 华4
1.湖南农业大学生物科学技术学院,洞庭湖区农村生态系统健康湖南省重点实验室;2.新疆农业大学草业与环境科学学院;3.青岛农业大学资源与环境学院;4.中国科学院生态环境研究中心城市与区域生态国家重点实验室
摘要:
全面认识桉树种植对土壤微生物群落结构和功能的影响及机制,对于阐明单一物种对生态系统服务功能的影响具有重要意义。通过室内小盆模拟控制试验,采用随机区组设计,以土壤碳、氮含量有显著差异的3种天然次生林土壤为对象,以不添加凋落物的处理和添加天然次生林混合凋落物的处理为对照,研究桉树凋落物对土壤微生物群落结构及功能的影响。结果表明:(1)与天然次生林的混合凋落物相比,桉树凋落物具有较高的碳含量和较低的氮含量,其碳氮比也较高;(2)添加桉树凋落物的土壤中细菌、真菌、放线菌以及磷脂脂肪酸的总丰度显著高于不添加凋落物的土壤,但是显著低于添加天然次生林混合凋落物的土壤,并且不同凋落物处理下土壤微生物群落的磷脂脂肪酸组成存在显著差异;(3)不同凋落物处理下土壤微生物群落的碳代谢方式差异显著,添加桉树凋落物的土壤微生物群落的碳代谢功能优于未添加凋落物的处理,但是显著低于天然次生林混合凋落物处理的土壤,包括:碳代谢的活性和多样性。综上所述,与天然次生林本身的凋落物相比,桉树凋落物影响下的土壤微生物群落的生物量、多样性和代谢活性均较低,表明桉树凋落物为土壤微生物群落提供生境和食物的能力较弱。
关键词:  桉树  天然次生林  凋落物  土壤微生物
DOI:10.11766/trxb201804200092
分类号:
基金项目:国家自然科学基金项目(41501325,40871130,41501271)
Impacts of Litter Decomposition of Eucalyptus on Soil Microbial Community:A Microcosm Study
CHEN Falin1, ZHANG Kai2, XIANG Dan3, WU Aiping1, LI Youzhi1, ZOU Dongsheng1, ZHENG Hua4
1.Hunan Provincial Key Laboratory of Rural Ecosystem Health in Dongting Lake Area, College of Bioscience and Biotechnology, Hunan Agricultural University;2.College of Grassland and Environment Sciences, Xinjiang Agricultural University;3.College of Resources and Environment, Qingdao Agricultural University;4.State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences
Abstract:
【Objective】Eucalyptus is one of the main tree species introduced into the country for afforestation because of its fast growth and economic value. By the end of 2015, its plantation had expanded up to 4 500 000 hm2. Afforestation of fast-growing Eucalyptus has received considerable attention with regard to its impacts on forest ecosystem. It is now known to affect physical and chemical properties of the soil, and plant community biodiversity. A number of studies have shown that it causes the soil degrading once it takes the place of native forests, but still little has been reported on its effects on soil microbial communities in South China. Soil microbial communities play a central role in litter decomposition, nutrient mineralization, and nearly all soil ecological processes in forest ecosystems, and may serve as an early indicator of changes in soil because of its rapid response to anthropogenic disturbances relative to soil biogeochemical properties. Litter decomposition provides the main source for soil microbial communities in forest ecosystems, whereas decomposition of Eucalyptus litter can disrupt the ecological associations between soil microbial communities and previous native communities. It is, therefore, very important to understand impacts of decomposition of Eucalyptus litter on structure and functions of the soil microbial community and its mechanisms to elucidating impacts of a single plant species on ecosystem services. 【Method】 A simulation pot experiment was laid out in random block design and designed to determine impacts of Eucalyptus litter on structure and functions of the soil microbial community by means of comparison with mixed litter of natural secondary forest. Three types of natural secondary forest soils different in soil carbon and nitrogen contents were used in the experiment. A portion, 2 g each, of air-dried litter was mixed separately with 200 g (dry weight) soil in each pot, except for control (no litter added). Structure and functions of the soil microbial community in the soil of each pot were determined with the PLFA (phospholipid fatty acids) and BIOLOG (single carbon metabolism) methods, 10, 20 and 30 days after the decomposition started. 【Result】 Results show: (1) Eucalyptus litter was higher in carbon content but lower in nitrogen content than the litter of natural secondary forest, and so significantly higher in carbon-nitrogen ratio; (2) PLFA abundances of bacteria, fungi, actinomyces and total PLFA were significantly higher in the soil treated with Eucalyptus litter than in the soil of the control, but significantly lower than in the soils treated with natural secondary forest litter; Principal component analysis (PCA) of the PLFA data shows that the treatment of Eucalyptus litter differed significantly from the treatments of mixed natural secondary forest litter in soil microbial community structure, and principal component one (PC1) explained 84.02% of the variation; and (3) PCA of the BIOLOG data also shows that significant differences existed between treatments in carbon utilization profiles of the soil microbial community, and PC1 and PC2 explained 36.99% and 16.95% of the variation, respectively; the treatment of Eucalyptus litter significantly lower than the treatments of natural secondary forest litter in carbon metabolic intensity, richness and diversity of soil microbial community, too. 【Conclusion】 All the findings in this study demonstrate that Eucalyptus litter is lower in capability of supplying soil microbial communities with adequate habitat and food than the mixed natural secondary forest litter.
Key words:  Eucalyptus   Natural secondary forest  Litter  Soil microbe