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

Key words: Cole, Plasmodiophora brassicae, Resting spore, Modality, Biological characteristic