磷脂脂肪酸法分析地黄根际土壤微生物多样性

Analysis of Soil Microbial Diversity in Rehmannia glutinosa Rhizosphere with Phospholipid Fatty Acid Method

应用磷脂脂肪酸法(PLFA)分析了1年生、2年生和5年轮作地黄根际土壤微生物群落多样性。研究发现,地黄连作障碍在2年生和5年轮作田均发生,表现为病虫害严重,根系生长不良,根际土壤微生物基础呼吸、代谢商高于对照等,说明地黄根际生态系统的代谢能力降低,可能影响到能量循环过程。应用主成分分析法从33个PLFAs中提取出3个主成分,代表72.55%的变异信息,其中PCI解释了48.91%的变异,PC2解释了14.16%的变异,PC3解释了9.48%的变异,而且从主成分得分图上可以很明显区分根际和非根际土壤。另外还发现地黄根际真菌标志磷脂C18:2ω6,9显著高于非根际的对照土壤,这可能和根际病害发生有关。

The ester-linked phospholipid fatty acid （PLFA） method was used to evaluate soil microbial community diversity in Rehmannia glutinosa fields different in cultivation history, i.e. one year cropping （Treatment Ⅰ）, two years of continuous cropping （Treatment Ⅱ）, and five years of crop rotation （Treatment Ⅲ）. In field investigations, barrier to continuous cropping was observed not only in Treatment Ⅱ, but also in Treatment Ⅲ and demonstrated as serious infection of pest/disease, and poorer development of the root system and higher rhizospheric soil microbial basic aspiration and metabolic quotients than in Treatment Ⅰ （CK）, all suggesting that the metabolic capacity of the rhizospheric ecosystem of Rehmannia glutinosa was reduced, which might possibly affect energy recycling. Of thirty-three PLFAs analyzed with the principal component analysis （PCA） method, three principal components were screened out, representing 72.55% of the information of diversity. Among the three, PC I explained 48.91% of the variation, PC2, 14.16%, and PC3, 9.48%, which helped successfully distinguish rhizosphere from non-rhizosphere in the principal components scores charts. In addition, it was found that the abundance of PLFA C 18：2ω6,9, which is a biomarker of soil fungi, was much higher than in the non-rhizosphere, which might be explained by infection of the root system.