为动态比较土壤垦殖前后微生物群落代谢功能是否发生变化,利用Biolog-Eco技术对不同季节自然恢复(NR)和垦殖不同施肥处理[不施肥(NoF)、施化肥(CF)和化肥配施有机肥(CFM)]黑土微生物在4℃、15℃和28℃培养温度下的代谢功能多样性进行了研究。结果表明:4种处理在同一采样时期不同培养温度下,Biolog微孔板的单孔平均颜色变化率(Average Well Color Development,AWCD)值均表现为28℃>15℃>4℃,即微生物代谢活性随培养温度的升高而升高;同一采样时期样品在相同培养温度下黑土微生物对碳源的代谢能力总体呈现为NR>CFM>CF>NoF。微生物在积雪融化期和积雪覆盖期对碳源的利用能力高于植物生长季节。主成分分析(Principle Component Analysis,PCA)结果显示,不同采样时期NoF样品和其它3种处理相比微生物功能多样性差异较大;NR、CF和CFM在作物非生长季节(3月、4月和12月)的样品在PCA图中分散度小于在作物生长季节(6月)的样品。该研究结果综合表明,垦殖处理较自然恢复降低了土壤微生物群落对碳源的代谢能力,但并未改变微生物群落功能;不同季节土壤微生物功能多样性存在差异,NR、CF和CFM细菌群落在作物生长的夏季对碳源的利用能力差异最大。
Soil microbial biomass and community structures are commonly used as indicators for soil quality and fertility. A investigation was performed to study the effects of long-term natural restoration, cropping, and bare fallow managements on the soil microbial biomass and bacterial community structures in depths of 0-10, 20 30, and 40-50 cm in a black soil （Mollisol）. Microbial biomass was estimated from chloroform fumigation-extraction, and bacterial community structures were determined by analysis of 16S rDNA using polymerase chain reaction-denaturing gradient gel electrophoresis （PCR- DGGE）. Experimental results showed that microbial biomass significantly declined with soil depth in the managements of restoration and cropping, but not in the bare fallow. DGGE profiles indicated that the band number in top 0-10 cm soils was less than that in depth of 20-30 or 40-50 cm. These suggested that the microbial population was high but the bacterial community structure was simple in the topsoil. Cluster and principle component analysis based on DGGE banding patterns showed that the bacterial community structure was affected by soil depth more primarily than by managements, and the succession of bacterial community as increase of soil depth has a similar tendency in the three managements. Fourteen predominating DGGE bands were excised and sequenced, in which 6 bands were identified as the taxa of Verrueomicrobia, 2 bands as Actinobacteria, 2 bands as α-Proteobacteria, and the other 4 bands as 8-Proteobacteria, Aeidobacteria, Nitrospira, and unclassified bacteria. In addition, the sequences of 11 DGGE bands were closely related to uncultured bacteria. Thus, the bacterial community structure in black soil was stable, and the predominating bacterial groups were uncultured.
WANG Guang-Hua JIN Jian LIU Jun-Jie CHEN Xue-Li LIU Ju-Dong LIU Xiao-Bing
