The Biological Characteristics Of Rape Clubroot Pathogen

Rape clubroot is a root disease,caused by plasmodiophora Brassicae.In the experimentation, rape root of clubroot disease from Huangshan city of Anhui province was used as material, distilled the resting spores of P.Brassicae, the effects of different factors on the resting spore’s germination,was studies, the main results were showed as follows:1. Effects of different matrix solutions on the germination of resting sporesThe germination rate of the resting spores in different solutions was investigated,the result showed that the germination rate of resting spores in filter-sterilized root exudates, untreated root exudates, hoagland nutrient solution, moist heat sterilization root exudates, sterile water,2% sucrose,5% glucose, and 2%maltose was 62.19%,56.27%,51.14%, 41.34%, 36.86%, 32.83%, 22.23% and 21.56%, respectively. The results suggest that if sterile water was used as a control, host root exudates could promote the germination of resting spores, and the germination rate of resting spores was the highest in the root exudates, three kinds of sugars inhibited the germination of resting spores.2. Effects of temperature, pH and visible light on the resting spores’s germinationThe appropriate temperature for germination of resting spores of P.Brassicae in canola was form 20 to 28℃, the optimal temperature was 24℃,the lethal temperature was 48 ℃; Germination of the resting spores’was better in weak acid solution, the appropriate pH of resting spores’s germination was form 6.0 to 6.5, the germination rate of resting spores was the highest when pH was 6.3;The visible light inhibited the germination of resting spores.3. Effects of calcium and boron ions on the germination of resting sporesCalcium and Boron ions restrained the germination of resting spores, the germination rate of resting spores was decreased with the increasing of solution concentration. The resting spores which in calcium solution by Evans blue staining found that calcium affected the activity of resting spores, the death rate of resting spores was rise when increased the calcium solution concentration.4. Effects of different root exudates on the resting spores’s germinationGermination rate of resting spores in secretions of rape roots for clubroot-susceptibility, secretions of rape roots for clubroot-resistance, secretions of cabbage roots and secretions of corn roots was investigated, the result showed that the germination rate of resting spores was higher in secretions of rape roots for clubroot-susceptibility and clubroot-resistance,and the highest germination rate of spores was in secretions of cabbage roots and secretions of rape roots for clubroot-susceptibility, it indicated that secretions of corn roots for clubroot-susceptibility could promote the resting spores’s germination; The resting spores could germinate in secretions of corn roots, but the germination rate was low.5. Effects of root’s rot-treated on the resting spores’s germinationRotten treated of root was helpful to enhance the germination rate, accelerate its germination speed. The germination of resting spores extracted from rot-untreated root started about 3 days after culture, however the resting spores extracted from rotten treated of root had germinate 2 days after culture. At the end of the experiment,the germination rate of resting spores extracted from rotten treated(53.5%) was significantly higher than that of resting spores extracted from rot-untreated (23.77%).