柠檬酸和抗坏血酸对蝴蝶兰叶外植体褐变发生的影响

Effects of Citric Acid and Ascorbic Acid on Browning Leaf Explants of Phalaenopsis

目的:探究柠檬酸和抗坏血酸对蝴蝶兰叶片外植体褐变发生的影响以及对PPO活性变化影响的作用机理。方法:以褐变率和褐变指数为参考数据,分析柠檬酸和抗坏血酸对外植体PPO活性和PPO反应产物积累的影响以及与外植体褐变发生的关系。结果:分别用100mg/L柠檬酸共培养和50mg/L抗坏血酸浸泡处理叶片外植体,经离体培养3d,褐变率分别比对照降低94.9%和54.9%,离体培养6d,褐变指数低于对照的0.53,分别为0.46和0.36,同时PPO活性降低。结论:推测柠檬酸抑制褐变的原因是直接与酶蛋白作用,抗坏血酸则与新生醌类物质结合。

Objective：Effects of citric acid and ascorbic acid on browning of Phalaenopsis explants were studied,involving the changes of PPO activity.Method：Using the browning percentage and browning index as reference,the relation between PPO activity,the accumulation of PPO reaction products and browning was studied in leaf explants treated with citric acid and ascorbic acid.Result：100mg/L citric acid by co-culture treatment and 50mg/L ascorbic acid by immersion treatment could reduce the browning of explants tissue to the greatest extent.Compared with the control,the browning percentage of leaf explants treated with citric acid and ascorbic acid were 94.9% and 54.9% lower after cultured in vitro for 3d,respectively.And in vitro for 6d,browning index were 0.46 for 100mg/L citric acid by co-culture and 0.36 50mg/L ascorbic acid by immersion,lower than that of the control,which was 0.53.The PPO activity was reduced remarkably by citric acid and ascorbic acid.Conclusion：The effect of citric acid and ascorbic acid on PPO reaction product and product accumulation was analyzed and presumed that citric acid played a role in inhibit tissue browning by directly combined with PPO.However,ascorbic acid were combined with new quinines.