枯草芽胞杆菌在油菜根茎叶的定殖动态和生防作用研究

Root,stem and leaf colonization and biocontrolling against sclerotinia disease of rapeseed by Bacillus subtilis Tu-100

采用常规方法跟踪枯草芽胞杆菌Tu-100在缩影系统油菜根际的定殖情况。Tu-100在油菜不同根段部位的定殖密度从上到下呈现了逐渐递减的规律。随着接种后时间的延长而逐渐下降。在根段8 cm以外的根区几乎检测不到接种菌。在油菜播种后3d,定殖密度可达最高水平(8.3×105个/g),然后急速下降,30d后保持相对稳定的较低水平(1.3×102个/g)。在油菜三片真叶时喷雾接种一次,20d后,在茎和叶上不能检测到所接种的Tu-100,并且抗菌核病的能力也逐渐减弱。

Root colonization of rapeseed by Bacillus subtilis Tu -100 in rhizosphere microcosms was investigated with the aid of MPN method. Rape seeds were pelletized with Tu - 100, an effective bacterial ＂strain can promote rape seedling growth. Results indicated that the density of Tu - 100 populations increased gradually with distance from root tips of rapeseed and decreased gradually with time after sowing. Tu - 100 populations were not detectable on roots more than 8cm from the hypocotyl base. The population density of Tu - 100 on roots reached the maximum of 8.1 ×10^5 cfu · g^-1 3 days after sowing, and declined rapidly to relatively stable and lower populations （1.3 ×10^2 cfu · g^-1）in rhizosphere microcosms 50 days after sowing. Oilseed rape were inoculated by spraying when they had three leaves, Tu- 100 populations were not detectable on stems and leaves 20 days after spraying, and their resistance to Sclerotinia disease were decreased gradually with time.