不同品种西瓜接种辣椒疫霉菌后3种保护酶活性的变化

摘要

This research determined the relationship between watermelon phytophthora blight resistance and polyphenoloxidase (PPO) , peroxidase (POD) and phenylalanine ammonia-lyase (PAL). The changes of PPO , POD and PAL were measured in seedling stage of two watermelon resistant culti-vars,one susceptible cultivar and one highly susceptible cultivar inoculated by Phytophthora capsici. The 09-1-1 and 09-1-2 were resistant cultivars, GS-37 was a susceptible cultivar, G-S-12 was a highly susceptible cultivar. The stem/root tissues were studied before inoculation and the 2nd, 4th, 6th, 8th day after inoculation. The results showed that there was a close relation between watermelon phytophthora blight resistance and the activities of PPO , POD and PAL in its stem/root tissue. Before in-oculation in stem/root, the differences of the activities of PPO, POD were indistinctive bet-ween resistant cultivars and susceptible cultivars. But the difference of the PAL activity was distinctive, and the activities of resistant cultivars were higher than those of the susceptible cultivars. After inoculation in stems/roots, the enzyme activities were significantly higher in watermelon cultivars with different resistance, and the activities of resistant cultivars were higher than those of the susceptible cultivars all the time. The relative PPO, POD, PAL activity and watermelon phytophthora blight were possibly correlated with disease resistance of the tested watermelon cultivars.%探讨西瓜苗期疫病抗性与根茎组织中多酚氧化酶(PPO)、过氧化物酶(POD)和苯丙氨酸解氨酶(PAL)活性的关系.对2个抗辣椒疫霉菌西瓜品种(09-1-1和09-1-2)、1个感病西瓜品种(GS-37)和1个高度感病西瓜品种(G-S-12)进行苗期人工接种辣椒疫霉菌,并分别于接种当天(尚未接种)及接种后第2、4、6、8天采集西瓜根茎部组织,测定其中PPO、POD 和 PAL 活性的变化.结果发现,西瓜对疫病的抗性与其根茎组织中的PPO、POD 和 PAL 活性密切相关.接种前抗、感品种根茎组织中PPO、POD差异不明显,但PAL活性差异明显,抗病品种的PAL活性高于感病品种;接种后抗、感品种的PPO、POD和PAL活性都显著提高,而且抗病品种的酶活性始终高于感病品种.不同抗性西瓜品种对疫病的抗性与PPO、POD和PAL活性存在一定的正相关.