Effects of Tobacco Pathogens and Their Antagonistic Bacteria on Tobacco Root Exudates

The research on relationship between rhizosphere microbes and root exudates has a great significance on discussion of interaction between rhizosphere microbes and plants, as well as control of soil-borne diseases and insect pest. GC-MS was used to analyze changes of tobacco root exudates under the antagonistic action of tobacco bacterial wilt and black shank. It turned out that when pathogens of tobacco bacterial wilt and black shank in tobacco root microorganisms increase, tobacco root exudates augmented rapidly among of which organic acids have the biggest growth, followed by amines. When the pathogens of tobacco bacterial wilt and black shank are inhibited by the active substance of antagonistic antibacterial, 20 - 23 kinds of root exudates are added; besides, the content of 7 substances was reduced to 0. Another inter-esting finding was that the fluctuations of phthalic acid, isophthalic acid and benzoic acid, which have caused continuous cropping obstacles, were very dis-tinct. The results of this study have provided novel clues for the exploration of continuous tobacco cropping obstacles and soil-borne diseases.