Abstract:
The leaves of tobacco plants of two cultivars with different resistance, CV 87 and NC 89, were inoculated with
Alternaria alternata in greenhouse.The activities of peroxidase (POD), catalase (CAT), and phenylalanine ammonia-lysae (PAL) were determined at different times and leaf sequences after inoculation.The results showed that the activities of POD and CAT of resistant cv.CV 87 increased with the rising of leaf sequence, and susceptible cv.NC 89 increased and then decreased with the rising of leaf sequence.The POD activity of NC 89 was higher than CV 87, and CAT activity of CV 87 was higher than NC 89 with or without inoculation.The PAL activity of CV 87 increased, and that of NC 89 decreased after inoculation, the PAL activity of tobacco cv.was positively related to its resistance.