Effects of allelochemicals from different parts of Rehmannia glutinosa L. on the functional diversity of microbial flora in soil

Consecutive monoculture problem has seriously restrained the yield and quality of Rehmannia glutinosa L. Allelopathic autotoxicity is one of the most important reasons for the formation of plants consecutive monoculture problem, so it is particularly important to study the source of allelochemicals (root, leaf and root exudates) of R. glutinosa L. The paper investigated the changes in the functional diversities of microbial flora in soil during different periods after adding different carriers of allelochemicals from R. glutinosa L. (root, leaf and root exudates) to soil. By BIOLOG technology analyzing the growth of microbial flora feeding on phenolic acids and other carbohydrates as carbon sources of every treatments during different periods, the author studied the main source of allelochemicals. BIOLOG analysis results indicated that, when treated for 1 day, the root treatment was most conductive to the growth of the microbial flora feeding on polymers, amino acids, amine, carboxylic acids and carbo-hydrates as carbon sources, the leaf treatment was most conductive to the growth of the microbial flora feeding on phenolic acids as carbon sources, and the root exudates treatment爷s growth of microbial flora in soil was just better than the control. When treated for 30 60 90 180 days, the root treatment was best for the growth of the microbial flora feeding on phenolic acids as carbon sources, the leaf treatmen was most beneficial to the growth of microbial flora feeding on polymers, amino acids as carbon sources, while the root exudates treatment was not conductive to the growth of microbial flora feeding on all carbon sources.