黄瓜感染霜霉病菌叶片中一些酶活性的变化

 黄瓜抗病组合受霜霉病菌侵染的部位周围的叶组织内多酚氧化酶(PPO)活性的增加高于中抗和感病组合,而中抗组合又高于感病组合;抗性和中抗组合的过氧化物酶(PO)活性的增加高于感病组合;抗性组合苯丙氨酸解氨酶(PAL)活性的增加高于中抗和感病组合。抗性组合受侵后产生两条新的PPO同功酶带和两条新的PO同功酶带;中抗组合产生一条新的PPO同功酶带和一条新的PO同功酶带;感病组合只产生一条新的PO同功酶带,没有新的PPO同功酶带出现。

ON THE CHANGE OF ENZYME ACTIVITES OF CUCUMBER LEAF INFECTED BY PSEUDOPERONOSPORA CUBENSIS (BERK.ET CTRT) ROSWS.

The nature of resistance of cucumber to P. cubensis was studied with the assay for enzymes. Polyphenol Oxidase(PPO), Peroxidase (PO), Phcnylalanine Ammonia-Lyase(PAL). Results are as follows:In leaves of resistant cultivars, PPO activity increased by 1.5-1.6 times after infection. Besides, there were two new isoenzyme bands of PPO. In leaves of middle resistant cultivar, PPO activity increased by 1.2 times, and only one new isoenzyme band appeared.In Ieaves of susceptible cultivar, PPO activity increased by 1 time, and no new isoenzyme band appeared.In leaves of resistant cultivars, PO activity after infection increased by 3 times and two new isoenzyme bands appeared. In leaves of middle resistant cultivar, PO activity also increased by 3 times, and one new isoenzyme band appeared. In leaves of susceptible cultivar, PO activity increased by 2 times, and only one new isoenzyme band appeared.In leaves of resistant cultivars, PAL activity increased by 0.7-0.8 time after infection. In leaves of middle resistant cultivar,PAL activity increased by 0.4 time. This change of activity was also true for PAL in leaves of susceptible cultivars.