关键词: 油菜, 根肿菌, 休眠孢子, 形态, 生物学特性

Abstract: Recently, the incidence of crucifer clubroot in rape is gradually increases. This text reports the modality of resting spores of crucifer clubroot in rape. The resting spores are nearly spherical, not slippery and mamillated on the wall in scanning electron microscope, their diameters range from 1.9 to 4.3 μm, and the mean is 3.5 μm. The primary zoospores with unequal length biflagellates are in nearly spherical, or nephroid, or oval shape in transmission electron microscope, and their size varies widely from 1.6 to 3.5 μm, and the mean is 2.8 μm. It is observed that the changing course of the resting spores turn into the primary zoospores, the silent spores in order, and then one silent spore germinates out a tubal structure. The optimum temperature for the germination of resting spores is 24 ℃, the optimum pH is 6.3. Treatment of rotted clubs is helpful to enhance the germinated rate. The visible light inhibit the germination of the resting spores. The highest germinated rate for the resting spores is 62.50% in the root exudates. The results show that the conditions for the germination of resting spores are accordant with the disease's generant condictions.

Key words: rape, Plasmodiophora brassicae, resting spore, modality, biological characteristic