Effects of Plasmodiophora brassicae toxin on physiological characteristics and growth of rape seedlings

Effects of Plasmodiophora brassicae toxin on the radicle and embryo growth, seedling wilting, cell membrane permeability, chlorophyll content, root activity and seedling growth of rape were studied to explore the pathogenic mechanism of P. brassicae Woron by water culture method. The results indicated that the toxin had significant biological activity, could inhibit the growth of radicle and embryo. The wilting degree of seedlings increased with extension of culturing time and toxin concentration. The rape under toxin exhibited an increase in membrane permeability but a decrease in chlorophyll content and root activity, especially chlorophyll b content firstly enhanced and then decreased with the increase of treatment time. With toxin concentration rising, seedling height and root length appeared gradually decreasing trend and dramatically lower than CK at 85% and 100% concentrations of toxin. It showed that the plant growth at this time was inhibited obviously.