蝴蝶兰外植体酚类物质和活性氧代谢与组培褐变的关系

The Metabolism of Phenolics and Reactive Oxygen Species in Relation to the Explant Browning Differences Among the Varieties of Phalaenopsis During the Tissue Culture

为探明蝴蝶兰组培褐变的生理机制,以组织培养过程中褐变程度不同的蝴蝶兰品种B3、15和F5为试材,对叶片外植体组培过程中酚类物质代谢及活性氧代谢的相关指标进行了测定。结果表明,所用的3个品种叶片外植体中的总酚含量与PAL、POD活性呈正相关;总酚含量最低的品种B3褐变程度最严重,PPO活性及MDA含量始终最高;总酚含量最高的品种F5褐变程度最轻,PPO活性及MDA含量也最低,但品种F5的SOD和APX活性在整个培养过程中始终最高,说明蝴蝶兰叶片外植体组培褐变程度与总酚含量没有直接关系,褐变的发生与外植体膜脂过氧化损伤关系密切,并可能由PPO催化酚类物质氧化引起;PPO、SOD和APX活性的差异可能是造成3个蝴蝶兰品种叶片外植体组培褐变程度不同的主要原因。

The parameters of phenolic and reactive oxygen metabolism were measured in three varieties of Phalaenopsis,i.e.B3,15 and F5 to study the physiological mechanisms of explant browning as well as genotype differences.The total phenol contents of the three varieties were positively correlated with their PAL and POD activities.B3 with the lowest phenol content showed the highest browning degree,PPO activity and MDA content.F5 with highest phenol content had the lowest browning degree,as well as the lowest PPO activity and MDA content.Moreover,SOD and APX activities in F5 were the highest among the three varieties.These results suggested that the browning degree was not directly related to the total phenol content and that explant browning may be due to the phenol oxidation which catalyzed by PPO.Meanwhile,explant browning reflected the membrane damage caused by lipid peroxidation during the tissue culture of Phalaenopsis.The differences in the activities of PPO,SOD and APX possibly might be the main aspects that caused the genotype differences in tissue browning.