油菜皮壳中多酚氧化酶活性的组织化学检定及其与粒色的关系

以组织化学法及抑制剂处理研究了油菜种子成熟前皮壳中的多酚氧化酶活性有无、存在部位及其与粒色的关系。结果表明,甘蓝型和白菜型油菜种子成熟前,皮壳(包括种皮和糊粉层,下同)的栅栏层存在较强的多酚氧化酶活性;黄籽皮壳的活性略低于黑籽皮壳的,但当有足够的多酚化合物存在时,黄籽皮壳也能象黑籽皮壳一样变为黑色。黑籽油菜变色前的种子用抗坏血酸处理,多酚氧化酶活性受到抑制,呈色过程中断,种子呈纯黄状态。说明多酚氧化酶对籽粒的呈色极为重要。

HISTOCHEMICAL RESEARCH OF POLYPHENOL OXIDASE(PPO) IN SEED COAT AND THE RELATIONSHIP BETWEEN PPO AND SEED COLOR IN RAPESEED

The existence,location and relation with seed-coat color of PPO in rapeseed before maturation were investigated with histochemical method and treatment of ascorbic acid,it was proved that,before the maturation of seeds on plants,ths activity of PPO in(and only in)the palisade layer of seed coat(including aleurone layer)-was very active in B.napus and B.camp-estris.Although the activity of PPO in seed coat of yellow-seeded rape was not as active as that of black seeded rape,the seed coat of yellow-seeded rape still could get blackened if there were enough polyphenols presented,just as those of black-seeded rape did,Treated with ascorbic acid before seed blackening,seeds of black-seeded rape remained purely yellow instead of getting black,as the result of the inhibition of PPO activity.Therefore,it can be concluded that the activity of PPO is essential to the blackening of seeds in rapeseed.