發(fā)布時間：2018-03-10 08:48

  本文選題：纖維素　切入點：旱地　出處：《農業(yè)環(huán)境科學學報》2017年10期 　論文類型：期刊論文

【摘要】：為揭示農田土壤有機質中纖維素降解的微生物機制,依托紅壤丘陵區(qū)長期定位試驗,以兩種土地利用方式(旱地和水旱輪作地)下兩種施肥模式(化肥、秸稈還田配施化肥)的農田生態(tài)系統(tǒng)為研究對象,分析了表層土壤中纖維素含量、纖維二糖水解酶活性以及纖維素降解功能微生物豐度與群落結構的周年動態(tài)變化特征。結果表明:長期(13年)施肥后土壤中纖維素并未發(fā)生顯著積累,且從周年動態(tài)變化來看,秸稈還田后旱地和水旱輪作地中纖維素分別在6個月和3個月內完全降解或被轉化為其他形態(tài);相關分析表明,纖維二糖水解酶活性與纖維素含量呈顯著正相關,而真菌cbh I基因豐度與纖維二糖水解酶呈顯著正相關(P0.01),因此功能基因cbh I可用于指示本研究供試土壤中降解纖維素的關鍵微生物群;聚類分析表明,旱地和水旱輪作地的纖維素降解微生物(含cbh I基因)互相分離,即與施肥相比,土地利用方式是引起土壤中纖維素降解微生物群落組成改變最主要的因素;克隆測序結果顯示,兩種土地利用方式下纖維素降解功能微生物均以傘菌和糞殼菌占絕對優(yōu)勢,分別占總克隆庫的22.9%~39.5%(平均為34.7%)和17.7%~42.3%(平均為28.5%),其中秸稈還田后的纖維素降解過程可能由糞殼菌主導。研究結果闡明了紅壤丘陵區(qū)旱地和水旱輪作地中秸稈還田后纖維素降解及其功能微生物群落的異同,為揭示農田土壤新鮮有機質中易分解組分(纖維素)的微生物轉化機制提供了基礎數(shù)據(jù)。
[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.
【作者單位】： 湖南農業(yè)大學生物科技學院;中國科學院亞熱帶農業(yè)生態(tài)研究所亞熱帶農業(yè)生態(tài)重點實驗室;廣西科技大學;湖南農業(yè)大學南方糧油作物協(xié)同創(chuàng)新中心;
【基金】：國家重點研發(fā)計劃項目(2016YFD0200106-5) 國家自然科學基金項目(41671298,41301273) “西部之光”人才培養(yǎng)計劃~~
【分類號】：S154.3

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