桃种子的休眠与萌发研究──种皮的调控作用

Studies on Peach Seed Dormancy And Germination──The Effects of Seed Coat on Seed Dormancy

用桃品种秋香蜜去核壳种子，探索了种皮控制休眠与萌发的效应及作用机制。结果表明：①桃种子剥除种皮，休眠可被解除，出苗率与有皮种子经ＧＡｓ２００ｍｇ·ｌ￣（－１）浸种２４ｈ相近；种皮抑制萌发的效应与ＡＢＡ５ｍｇ·ｌ￣（－１）浸渍去皮种子２４ｈ相当。②桃新鲜种子内ＡＢＡ主要存在于种皮中，ＧＡ３主要存在于胚和子叶中，剥除种皮即人为地改变种子内ＧＡ＿３／ＡＢＡ值，有利于种子由休眠向萌发方向转化。③桃种皮对种子内过氧化物酶活性具强烈抑制作用；去皮种子的酶活性随ＧＡ３处理而增强，随ＡＢＡ处理而被抑制。④桃种皮无透水性障碍，种皮对种子的吸水总量虽有一定限制，但不影响种子萌芽。

The effects of seed coat on seed dormancy and germination were studied with Qiuxiangmi variety.Results showed:(1)Seed dormancy could be broken as soon as seed coat was removed;The seed germination rate was similar to that of seed soaked in GA_3 200mg·l￣(-1)for 24 hours;The effect of the coat inhibiting seed germina-tion was equal to that of seed soaked in ABA 5mg·l￣(-1) for 24 hours.(2) ABA exists mainly in seed coat in fresh-harvested peach seed,whereas GA_3 exists maily in embryo and cotylendon.Removing seed coat could shift the balance of GA_3/ABA,which was helpful to turn seed from dormancy into germination. (3)The seed coat could strongly inhibit peroxidase activity. Seed peroxidase activity could be promoted with GA_3 treatment and the activity could be inhibited with ABA treatment.(4)The seed coat was water-penetrable and the coat could limit the capacity of water absorption. But the limitation was not the main factor which inhibit seed ger-mination.