观赏海棠种子内源激素动态变化与胚胎败育关系

Correlation between Changes on Endogenous Hormones and Embryo Abortion of Ornamental Crabapple Seeds

【目的】探究观赏海棠种子内源激素赤霉素(GA_(3))、脱落酸(ABA)、细胞分裂素(CTK)、吲哚乙酸(IAA)等动态变化与胚胎败育关系。【方法】选取低败育率的红珠宝(M.Red Jewel)和高败育率的凯尔斯(M.Kelsey)为材料,分析果实生长发育过程中胚胎败育、内源激素含量的动态变化及相互间关系。【结果】凯尔斯在授粉后1~13 d挂果率急速下降,在授粉后54 d趋于稳定,红珠宝与凯尔斯的果实挂果率有显著差异(P<0.05)。在胚胎发育前期,低败育率的红珠宝种子内源激素GA_(3)、IAA含量及GA_(3)/ABA、(GA_(3)+IAA+CTK)/ABA比值显著高于高败育率的凯尔斯(P<0.05);在胚胎发育后期,低败育率的红珠宝种子内源激素GA_(3)、ABA、IAA含量及IAA/ABA、GA_(3)/ABA、(GA_(3)+IAA+CTK)/ABA比值显著低于高败育率的凯尔斯(P<0.05)。【结论】授粉后1~13 d是凯尔斯生理落果期,在生产上,该时期落果严重,是提高凯尔斯坐果率及果实观赏价值的最佳时期;授粉后1~54 d是红珠宝与凯尔斯胚胎败育发生的主要时期,大量胚败育果实在胚胎发育完成后并未脱落,而是持续生长到果实成熟,这与种子中高水平GA_(3)含量和(GA_(3)+IAA+CTK)/ABA比值没有下降反而升高有关。在胚胎发育早期,保持种子较高浓度GA_(3)和IAA能确保其正常发育,在胚胎发育晚期,种子内单一激素的高低无法确保胚胎的正常发育,低浓度的GA_(3)和IAA能确保其正常发育。

Objective Correlation between the changes on endogenous hormones and embryo abortion of ornamental crabapple seeds was investigated.Method Ornamental crabapple varieties,Malus Red Jewel with low abortion rate and M.Kelsey with high abortion rate,were compared on the endogenous hormones,including gibberellin GA_(3),abscisic acid ABA,cytokinin CTK,and indoleacetic acid IAA,in the seeds during fruit growth and development.The dynamic changes were correlated to the seed embryo abortion rate.Results There was significant difference on the fruit setting rate between M.Red Jewel and M.Kelsey(P<0.05)as that of M.Kelsey declined rapidly from one to 13 d and became stable at 54 d after pollination.In the early stage of embryonic development,the contents of GA_(3)and IAA and ratios of GA_(3)/ABA and(GA_(3)+IAA+CTK)/ABA in the seeds of M.Red Jewel were significantly higher than those of M.Kelsey(P<0.05).Conversely,in the later stage,the GA_(3),ABA,IAA,IAA/ABA,GA_(3)/ABA,and(GA_(3)+IAA+CTK)/ABA of M.Red Jewel became significantly lower than those of M.Kelsey(P<0.05).Conclusion The physiological fruit-dropping of M.Kelsey occurred in 1–13 d after pollination.It was the optimum time to alter the fruit-setting and improve the ornamental value of an M.tree.Embryonic abortion of both varieties of the crabapple took place within 54 d after pollination.Most of the fruits with aborted embryos did not fall off the tree and continued to grow to maturity due possibly to the increased GA_(3)and(GA_(3)+IAA+CTK)/ABA ratio in the seeds.Consequently,maintaining a high content of GA_(3)and IAA in the early stage could ensure a normal seed development.Once reached the late stage,no individual hormone,short of low level GA_(3)and IAA,could warrant a normal embryonic development.