三七种子后熟过程种胚发育和6种内源激素的动态变化

Embryo Development and Dynamic Changes of Six Endogenous Phytohormones During After-ripening Process of Panax notoginseng Seeds

目的:从形态和生理两个层面了解三七种子休眠和萌发的作用机理,以期为三七种子科学贮藏提供理论依据。方法:体视镜观测种胚发育情况,利用HPLC-MS测定不同后熟期内源激素的动态变化。结果:种子收获时,种胚已经初步分化但未发育完全,在三七种子后熟过程中,脱落酸(ABA)的含量整体呈现下降趋势,赤霉素(GA_3)和反式玉米素(tZT)先升高后降低,生长素(IAA)持续升高,茉莉酸(JA)和水杨酸(SA)无明显变化规律。后熟30天,GA_3/ABA、tZT/ABA和IAA/ABA的比值逐渐升高,其变化趋势与种胚长度和胚率的增加呈正相关,表明GA_3、tZT和IAA对三七种子萌发起到促进作用。结论:种胚发育不完全以及抑制物ABA的存在,可能是导致三七种子形态生理休眠的主要原因,内源激素之间平衡关系的改变是调控三七种子休眠解除与萌发的关键因素之一。

Objective:To unterstand the action mechanism of dormancy and germination of Panax notoginseng seeds from two aspects:morphology and physiology,in order to provide guidance for scientific storage of Panax notoginseng seeds.Methods:The development of embryo and changes of endogenous phytohormones were measured by stereoscopic microscope and HPLC-MS in different stages of the seeds.Results:The embryo has been initially differentiated but not fully developed when the fruits were mature.ripening period of 20 d.As the stratification time extended,the content of ABA had decreased in generally,the GA3 and tZT content increased at first and then decreased,the curve of IAA content had increased gradually.JA and SA were with a fluctuated trend.Before after-ripening period of 30 d,the ratio of tZT/ABA,GA3/ABA and IAA/ABA rised gradually,the trend of these comparison values with the trend of Em/En value became positive correlation,which proved that GA3,tZT and IAA has positive influence on the germination of seeds.Conclusion:The reason why morphphysiological dormancy of P.notoginseng seeds,is that the existed of incomplete embryo and ABA.The change of balance between hormones is one of the key factors to controll the dormancy and germination of Panax notoginseng seed.