西洋参种胚形态后熟过程中种子内源激素变化动态及其对种胚发育的调节

目的：阐述西洋参种胚形态后熟过程中内源激素与种胚发育的关系。方法激素测试用ＨＰＬＣ法，外标法定量，激素含量以ng/gfw表示；淀粉酶总活性测定用比色法，比色波长为５２０nm。结果在西洋参种胚形态后熟过程中嘴哚乙酸（ＩＡＡ）出现两次高峰。第一次峰值出现在层积开始后第８０天，第二次峰值出现在层积后１４０天，随后很快下降，霉素（ＧＡ３）在层积处理开始的第６０天有一个高峰。至第１２０以后以又开始持续升高。玉米索（Z）的变化动态与ＧＡ３相似，脱落酸（ＡＢＡ）的变化动态与内源ＩＡＡ的变化动态相似，不同之处是在层积开始后的前２０d一直没有检测到ＡＢＡ的存在。结论ＧＡ３和Ｚ是西洋参种子萌发促进因子，而不能启动原胚的起发育。ＡＢＡ第一个出现可能正是引起西洋参种胚起始发育的因子，第二个高峰则与种胚的快速发育一致，可能起着防止胚胎过早萌发的作用。

Dynamics of endogenous hormone in American ginseng seed during morphological after-ripening period and their regulation to embryo development

Object To aquire a deeper understanding of the relat i onshipbetween endogenous hormone and embryo development of the seed of Pa nax quinquefolius L. Methods The content of endogenous h ormone was determined by HPLC with the use of external standard and expressed in term of ng/gfw. Total amylase activity was assessed by spectrophotometry at λ 520 nm. Results During the after-ripening period of American gi nseng embryo, peak concentrations of indole acetic acid (IAA) appeared twice, on e on the 80th day and the other on the 140th day after stratification, and dec lined quickly thereafter. Abscisic acid (ABA) showed similar dynamics, except t hat it was undetectable during the first 20 d after stratification. gibberellic acid (GA3) and zeatin (Z) also showed 2 peaks, which appeared on the 60th an d 120th day, respectively. Conclusion GA3 and Z can promote germination of American ginseng seed, but cannot ignite the development of proem bryo. Probably the first peak of ABA was the factor for the ignition of embryo development, and the second peak runs in coincidence with the rapid development of the embryo and may inhibit the viviparity of American ginseng seed.