Change of 3 Kinds of Enzyme Activity and Soluble Sugar in 3 Chinese Cabbage Varieties with Different Resistance Level During the Process of Plasmodiophora brassicae Infecting Their Roots

There are different levels of resistance in Chinese cabbage varieties against clubroot.The content of catalase(CAT),peroxidase(POD),phenylalanin ammonia-lyase(PAL),Super Oxide Dismutase(SOD)and soluble sugar activities of 3cultivars with different clubroot-resistant levelswere detected after inoculation in this study.The results suggest that the changing rates of CAT,PAL and SOD contents of resistance cultivars after inoculation were higher than those of susceptible cultivars(Baigengbaiye>Zaobaicaitai>Huangjinxiaobaicai);the POD activities of resistance cultivars reached a peak on an earlier day than those of susceptible cultivars;the increasing rate of soluble sugar of susceptible cultivars was higher than that of the resistance cultivars,and ended with two peaks.Therefore,the four enzymes(CAT,POD,PAL and SOD)and soluble sugar may be used as physiological and biochemical reference indexes for the resistance identification to clubroot after inoculation with P.brassicae.

Studies on the Correlation between Germination and cAMP Content of Different Color Chlamydospores in Ustiloginoidea virens

Ustilaginoidea virens is the causal agent of a serious disease of rice. To reveal the relationship between germination and the 3'-5'-cyclic adenosine monophosphate(c AMP) content from the dormant(black or green-black) and non-dormant(yellow)chlamydospore in Ustiloginoidea virens,this study adopts ultrasonic-bath method and high-performance liquid chromatography(HPLC) method, for extraction c AMP content of the different color chlamydospore. The results demonstrated that, as for the freshly chlamydospores collected from the false smut balls during their germination, c AMP content of yellow chlamydospore appeared a slight growth during 0-12 h, and showed a rapid declining as the germination time extended(12-48 h). Above all, in yellow chlamydospores, the germination rate and the content of c AMP presented a very notably negative correlation(|r|=0.861 9>r0.01=0.834), but the correlation between germination rate and content of c AMP was not obvious in black chlamydospores. The germination rate and the content of c AMP presented a notably positive correlation under different storage period(0, 2, 4, 6, 8,10 months) of the two color chlamydospores(the yellow of chlamydospore: |r | = 0.785 1 > r0.05= 0.707; the black of chlamydospore: |r| = 0.957 9 > r0.05= 0.707).