Abstract: In order to explore the resistance mechanism of different rapeseed varieties to Leptosphaeria biglobosa, we analyzed the relation between the changes in contents and activities of defense enzymes peroxidase(POD), polyphemol oxidase(PPO), catalase (CAT), phenylalanine ammonia lyase (PAL) and superoxide dismutase (SOD) in different rapeseed cultivars with the infection process and varieties resistance.The activities of POD, PPO, CAT, PAL and SOD in resistant and susceptible rapeseed varieties before or after infected were measured using spectrophotometer.For uninfected plant, the resistance varieties had a higher activities of POD, PPO, CAT than susceptible varieties and had an almost the same values of PAL, SOD.After inoculation, resistant varieties showed higher sensitivity to Leptosphaeria biglobosa, the activities of five defense enzyme increased rapidly and reached the peak, the increment were significantly greater than susceptible materials.The enzyme activities of susceptible materials rise more slowly or later than resistant varieties. Leptosphaeria biglobosa can induced the changes of five defense enzymes in rapeseed, the enzyme activities of POD, PPO, CAT, PAL and SOD had a positive correlation with rapeseed resistance.These results suggested that early rapid increase of enzyme activities might be used as one of physiological indices for selection of rapeseed resistant varieties to L.biglobosa.

Key words: Rapeseed, Defense enzymes, Leptosphaeria biglobosa

CLC Number: 

• S432.2+2