Study On Some Physiological And Biochemical Characters Of Resistance (Tolerance) To Rhizomania In Sugar Beet

The relationship between activities of peroxidase(POD),polyphenol oxidase(PPO),chitinase,β-1,3-glucanase and content of superoxide anion radical ( )and ascorbic acid (ASA)and resistance to Rhizomania in sugar beet were studied in diseased soil and non-diseased soil by using a method of comparative physiology. Four sugar beet varieties including two resistant varieties and two susceptible ones were used in this experiment. The results showed: POD,PPO,chitinase andβ-1,3-glucanase activities of the resistant varieties were higher than the susceptible ones in either diseased soil or non-diseased soil；Similarly,the resistant varieties had higher ASA content than the susceptible ones；During the early phase of pathogen infecting,the resistant varieties had higher generating rate and content of than the susceptible ones. Subseqently content of the resistant varieties fell and became lower than the susceptible ones in the later period. So POD,PPO,chitinase,β-1,3-glucanase, and ASA were relevant to resistance to Rhizomania in sugar beet. In addition,the results of all indexes in diseased soil were higher than that in non-diseased soil to some extent. It suggested that pathogen infecting lead to an increase in enzymes activities and content of substance related to resistance to Rhizomania. This research will not only clarify the physiological and biochemical mechanism of resistance to Rhizomania on enzymes and substance but also provide a theoretical basis for selecting and breeding physiologically new varieties in sugar beet.