金冠苹果果实发育后期内源脱落酸的来源与代谢

Source and Metabolism of Abscisic Acid in Apple( Malus pumila Mill cv.Golden Delicious)Fruits during the Late Stage of Development

苹果果实发育后期（含成熟期），脱落酸（ＡＢＡ）浓度从果枝的叶片和茎到果柄、果心、果肉，呈由高到低的梯度分布。果实自身具有合成ＡＢＡ的能力。ＡＢＡ从叶片等外部器官向果肉、果心的运入量占其自身合成量的４０％～５０％，向种子的运入量占其自身合成量的１０％左右。从短果枝叶片经叶柄向树体引入３ＨＡＢＡ后，放射性ＡＢＡ成分优先向种子运输，其次向果心和果肉同步运入，放射性ＡＢＡ在果台茎中的半衰期为４．１６ｈ；从果心向果实引入３ＨＡＢＡ后，放射性ＡＢＡ在果心组织中的半衰期为２．３６ｈ，被迅速代谢，３ＨＡＢＡ经果柄向果实外的运输很微弱。经ＡＢＡ生物合成抑制剂Ｆｌｕｒｉｄｏｎｅ处理后，果实各部位内源ＡＢＡ合成被显著抑制。

The source and metabolism of phytohormone abscisic acid(ABA)was investigated in Golden Delicious apple.The results showed that a concentration gradient of ABA,from high to low,existed from leaves to fruit core(leaves>stem>pedicle>flesh≈core),during the late stage of fruit development.This suggests a movement of ABA out of leaves into fruits.The apple fruit was shown to be capable of synthesizing ABA in situ for its development control according to the results obtained in the research.The ABA concentration was much higher in seeds than that in flesh and core tissues.The percentages of the biosynthesized ABA by flesh and core of fruits were about 40%～50% of the total ABA in these tissues,a little lower than that of the ABA transported in from leaves and other organs.The percentage of the biosynthesized ABA by seeds was shown to be 90% of the total ABA in seeds,and the rest was believed to be transmitted from other organs or tissues.The 3H ABA fed in apple tree via the petiole of bourse leaf below the fruits was privileged to be transported into the seeds,and afterwards,into flesh and core tissues nearly at the same time.The half life of 3H ABA fed in core directly via core cavity was 2.36 hours,which was much shorter than that of 3H ABA in fruiting shoot when it was fed via petiole.The 3H ABA fed via core cavity was shown to be scarcely transported out of fruits through pedicle.Fluridone,an inhibitor of ABA biosynthesis,inhibited greatly ABA synthesis in every part of fruit.