荔枝种子脱水敏感性与组织褐变的关系

荔枝种子在贮藏过程中对脱水高度敏感,随着种子含水量下降,种子的发芽率、活力指数和总酚含量下降;多酚氧化酶活性先上升然后迅速下降。其脱水敏感性的原因可能是荔枝种子膜的完整性受到损伤,酚类物质和多酚氧化酶的细胞内分室作用丧失,酚类被氧化成醌,从而毒害细胞,加速种子的劣变和死亡。

Desiccation-sensitivity of Lychee (Litchi chinensis Sonn.) Seed in Relation with Tissues Browning

Lychee seed is of high desiccation- sensitivity during storage. When water content of seed declined, germination percentage, vigour index and content of total phenols decreased. In the meantime, the activity of polyphenol oxidase, first incr-eased and then rapidly decreased. The reason why lychee seed was sensitive to desiccation could be that membrane integrity was damaged, and that intracellular compartmentations of phenolic compounds and polyphenol oxidase were lost. And then phenolic compounds were oxidized into quinones when lychee seed was desic-cated. Therefore, cells were poisoned, and deterioration and death of seeds were accelerated.