蝴蝶兰外植体褐变发生与总酚含量、PPO、POD和PAL的关系

 蝴蝶兰外植体在褐变发生前期PPO和POD活力皆升高, 褐变发生后酶活力下降。同工酶谱分析发现, 培养0 d的蝴蝶兰外植体PPO没有酶带出现, 而POD有1条弱带。离体培养2 d POD出现3条酶带, 第4天有新酶带Ⅰ发生, 随后消失, 其余3条带, 随培养天数的延长, 酶带活性渐弱。PPO同工酶谱在培养2 d出现3条酶带, 迁移率为0128的酶带Ⅲ在培养4 d活性较强, 随后3条酶带减弱。总酚含量和PAL活力随外植体褐变增强而逐渐增加, 两者呈现极显著正相关。

Changes of Total Phenol Content and the Activities of PPO, POD and PAL during the Browning in Phalaenopsis Explant in Vitro

In the early stage of Phalaenopsis explant browning, the activities of PPO and POD increased, while in the later stage, their activities declined. The PPO and POD isoenzyme showed that no PPO band appeared in 0 day culture, while a weak band of POD appeared. After 2 days culture, there were three bands of POD appeared, and the band I appeared after cultured for 4 days and dispersed in another day; and three bands of PPO isoenzyme in browning cell appeared and the band II1 had a higher activity when cultured for 4 days, the activitives of PPO and POD declined whit the culture extension. As explant turned black, the content of total phenol compounds and the activity of PAL increased and there was a extremely positive correlation between them.