红壤丘陵区旱地和水旱轮作地土壤中纤维素降解功能微生物群落特征

发布时间：2018-03-10 08:48

本文选题：纤维素　切入点：旱地　出处：《农业环境科学学报》2017年10期 　论文类型：期刊论文

【摘要】：为揭示农田土壤有机质中纤维素降解的微生物机制,依托红壤丘陵区长期定位试验,以两种土地利用方式(旱地和水旱轮作地)下两种施肥模式(化肥、秸秆还田配施化肥)的农田生态系统为研究对象,分析了表层土壤中纤维素含量、纤维二糖水解酶活性以及纤维素降解功能微生物丰度与群落结构的周年动态变化特征。结果表明:长期(13年)施肥后土壤中纤维素并未发生显著积累,且从周年动态变化来看,秸秆还田后旱地和水旱轮作地中纤维素分别在6个月和3个月内完全降解或被转化为其他形态;相关分析表明,纤维二糖水解酶活性与纤维素含量呈显著正相关,而真菌cbh I基因丰度与纤维二糖水解酶呈显著正相关(P0.01),因此功能基因cbh I可用于指示本研究供试土壤中降解纤维素的关键微生物群;聚类分析表明,旱地和水旱轮作地的纤维素降解微生物(含cbh I基因)互相分离,即与施肥相比,土地利用方式是引起土壤中纤维素降解微生物群落组成改变最主要的因素;克隆测序结果显示,两种土地利用方式下纤维素降解功能微生物均以伞菌和粪壳菌占绝对优势,分别占总克隆库的22.9%~39.5%(平均为34.7%)和17.7%~42.3%(平均为28.5%),其中秸秆还田后的纤维素降解过程可能由粪壳菌主导。研究结果阐明了红壤丘陵区旱地和水旱轮作地中秸秆还田后纤维素降解及其功能微生物群落的异同,为揭示农田土壤新鲜有机质中易分解组分(纤维素)的微生物转化机制提供了基础数据。
[Abstract]:In order to reveal the microbial mechanism of cellulose degradation in farmland soil organic matter, two fertilization modes (chemical fertilizer) were used under two land use modes (dry land and dry land), relying on long-term localization experiment in red soil hilly region. The content of cellulose in the surface soil was analyzed. The annual dynamic characteristics of cellulolytic hydrolase activity, microbial abundance and community structure of cellulose degradation function were studied. The results showed that there was no significant accumulation of cellulose in soil after long-term (13 years) fertilization, and from the point of view of the annual dynamic change, there was no significant accumulation of cellulose in soil after long-term (13 years) fertilization. Cellulose was completely degraded or transformed into other forms within 6 months and 3 months after straw was returned to dry land and dry rotation, respectively. Correlation analysis showed that the activity of cellulose hydrolase was positively correlated with the content of cellulose. However, there was a significant positive correlation between the abundance of cbh I gene and cellulolytic hydrolase. Therefore, the functional gene cbh I could be used to indicate the key microbial community of cellulose degradation in the soil of this study. Cellulose degrading microorganisms (including cbh I gene) in dry land and dry rotation were separated from each other. Compared with fertilization, land use pattern was the most important factor to change the composition of cellulose degrading microbial community in soil. The results of cloning and sequencing showed that Umbellae and fecal shell bacteria were the dominant microorganisms in cellulose degradation under two land use patterns. 22.9% of the total clone bank accounted for 39.5% (mean 34.7) and 17.7% and 42.3% (average 28.553%), respectively. The cellulose degradation process after straw returning to the field may be dominated by fecal bacteria. The results show that the cellulose degradation process of dry land in red soil hilly area and that of crop straw in rotation field after returning straw to field is probably dominated by fecal shell bacteria. The similarities and differences of the degradation of vitamin and its functional microbial communities, The basic data were provided for revealing the microbial transformation mechanism of the decomposable components (cellulose) in the fresh organic matter of farmland soil.
【作者单位】：湖南农业大学生物科技学院;中国科学院亚热带农业生态研究所亚热带农业生态重点实验室;广西科技大学;湖南农业大学南方粮油作物协同创新中心;
【基金】：国家重点研发计划项目(2016YFD0200106-5) 国家自然科学基金项目(41671298,41301273) “西部之光”人才培养计划~~
【分类号】：S154.3

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