半夏防御酶系对Fusarium oxysporum和Phytophthora parasitica侵染的动态反应

尖孢镰刀菌(Fusarium oxysporum Schlecht)和寄生疫霉(Phytophthora parasitica Dastur)分别为引起半夏块茎腐烂病和疫病的病原,为探索半夏在受到这2种病原侵染时的生理生化反应,采用室内盆栽方法,研究超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)、多酚氧化酶(PPO)、苯丙氨酸解氨酶(PAL)5种寄主防御酶活性在块茎腐烂病和疫病发生过程中的变化趋势。结果表明,半夏在接种2种病原菌后,分别于第2天和第3天出现发病症状,第5天病情指数分别高达70.3、70.6;SOD活性都于接种后第1天达到高峰,POD活性都于接种后第3天达到高峰,CAT活性都于接种后第2天达到高峰,PAL活性分别于接种后第2天和第3天达到高峰,而PPO活性分别于接种后第3天和第4天有小幅上升。初步表明,在寄主显症之前或发病初期酶活性达到高峰的SOD、POD、CAT、PAL在半夏抗病生理机制中起着重要作用,在半夏抗病种质筛选时需要重点关注。

Dynamic responses of the defensive enzymes in Pinellia ternate to Fusarium oxysporum and Phytophthora parasitica

The activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), polyphenol oxidase (PPO) and phenylalanine ammonia-lyase (PAL) were studied in the leaves of peach-leaf type Pinellia ternata inoculated with Fusarium oxysporum Schlecht and Phytophthora parasitica Dastur. The results showed that the disease index of P. ternate inoculated with F. oxysporum and P. parasitica were 70.3 and 70.6 on the fifth day, respectively. The peaks of SOD, POD and CAT, treated with F. oxysporum and P. parasitica, were observed on the first, third and second day, respectively. The peak of PAL inoculated with F. oxysporum and P. parasitica were observed on the second day and the third day. The activities of PPO inoculated with F. oxysporum and P. parasitica rose slightly on the 3rd day and the 4th day, respectively. These results preliminarily showed that the activity of SOD, POD, CAT and PAL should be considered in screening varieties.