离心操作对BIOLOG法测定微生物群落功能多样性的影响

陆地生态系统的有机质分解是地球系统碳循环的重要环节,但目前人们对这一过程的认知程度尚待提高,原因之一是对植物凋落物分解时微生物群落功能多样性的变化缺乏系统认识.如能将BIOLOG微平板法引入植物凋落物降解初期的研究中,将弥补这一重要环节的缺失.但当前对如何在降解初期研究中应用这一方法、尤其是对于在预处理过程中是否应进行离心操作并无定论.为此,笔者选用北京桦树林区凋落物的淋洗液为接种液,考察离心操作对BIOLOG微平板法测定结果的影响.研究发现:离心操作能减小培养液的浊度(吸光度减小0.13)、降低溶液颜色对微孔显色程度的干扰,但也会导致测得的微生物群落数量减少(平均颜色变化率可降低约0.4);样品中微生物群落数量越小,群落功能多样性受影响的程度则越大.因此,在选择是否进行离心操作时,需针对具体的研究对象综合选择.

Centrifugation Effect on the Functional Diversity of Microbial Community in Fallen Leaves Displaying in BIOLOG Micro-Plates

The decomposition of organic matter in terrestrial ecosystem is an important link in the global carbon cycle;however,and the knowledge of this process are still not sufficient.One of the reasons is the lack of a systematical recognition to the changes of microbial community functional diversity during a decomposition of plant litter.Things will get better if the method of BIOLOG micro-plates can be introduced into the initial degradation process of plant litter.Unfortunately,there was no conclusion on how to use this method to the initial degradation,and whether a centrifugal operation should be used during the process of pretreatment.We choose the eluting solution of Beijing birch forest litter as inoculums and consider the effects of centrifugal operation on the BIOLOG micro-plates.The results show that centrifugation can reduce the turbidity (absorbance decreases 0.13 ) and the interference of color to the solution.At the same time,centrifugation could reduce the measured quantity of microbial communities (AWCD value can be reduced by 0.4).The less the quantity of microbial communities in the sample is,the greater the impact on the functional diversity of soil microbial communities is.Therefore,a specific study target should be the judging basis to determine whether a centrifugation is used for its pretreatment.