Effects of BTH on Activities of POD and PPO in Resistant and Susceptible Melon Seedlings Challenged with Gummy Stem Blight

In this study,the activities of POD and PPD in melon were analyzed after benzothiadiazole(BTH) treatment and gummy stem blight(GSB) inoculation. The results showed that the activities were enhanced in different GSB resistant melons.The activities of POD and PPO in the third and fifth leaves of PI420145 and ‘Elizabeth' treated with BTH were higher than that of control(t-test,P0.05) on the first,second and fourth day post treatment. Similarly,the activities of POD and PPO were higher in the third and fifth leaves which were treated by both BTH and GSB inoculation than just GSB inoculation on the eighth,tenth,twelfth and fifteenth day post treatment. The POD and PPO activities were higher in PI420145 than ‘Elizabeth'in all the situations. These results indicate that the improved resistance of GSB in melon is associated with the increased POD and PPO activities.