椭圆叶花锚种子内源激素对储藏的响应及其与种子萌发的关系

The response of endogenous hormones to storage and their effects on seed germination of Halenia elliptica

内源激素作为调控种子萌发与休眠的主要内因一直备受关注,但其随环境条件改变的变化规律及其对种子萌发的调节机制一直缺乏普遍接受的理论或假说。本研究以广泛分布于青藏高原东北缘高寒草甸的椭圆叶花锚种子为研究材料,分析不同储藏条件和时间对椭圆叶花锚种子内源激素含量的影响,及其与种子萌发的关系。结果表明:不同储藏条件下,椭圆叶花锚种子中内源激素含量随储藏时间变化差异显著;常温条件下,储藏时间对内源激素的绝对含量及各生长促进物与抑制物的比值(IAA/ABA除外)均有较显著的影响,而在冷藏条件下,储藏时间仅对GAs、IAA、ABA和促进物总量有较显著的影响;储藏条件和时间对椭圆叶花锚种子的萌发率均有极显著影响;常温储藏条件下种子萌发率大约是冷藏条件下的4倍,且种子存在休眠循环;椭圆叶花锚种子萌发并不是促进类激素或抑制类激素绝对含量的升降调节的;种子萌发与GAs含量显著正相关、与IAA含量显著负相关,CTK的含量达到一定高度的时候,萌发率才能达到最高。因此,本研究中各内源激素的作用关系,与Khan提出的三因子学说相一致,即CTK与ABA相拮抗,减轻或消除ABA的萌发抑制作用,从而使GAs的作用表现出来。

Endogenous hormones are considered as a main internal cause to regulate germination and dormancy of seeds,which have been highly concerned.However,no theory or hypothesis on the change patterns of endogenous hormones with environmental changes and their regulation mechanisms on seed germination has been generally accepted.In this study,seeds of Halenia elliptica which is widely distributed in the alpine meadow of northeastern Qinghai-Tibet Plateau were used to test the dynamics of endogenous hormone content and germination under different storage temperatures and durations.The contents of endogenous hormones of seeds varied with storage duration under different storage temperatures.Under room temperature,the effects of storage duration on the absolute contents of endogenous hormones and the ratios of promoters to inhibitors（except IAA/ABA） were significant.Under cold storage,the effects of storage duration on the contents of GAs,IAA,ABA and total promoters were significant.Storage duration and storage temperature significantly influenced the germination percentage.The seed germination percentage under room temperature was about 4 times as high as that under cold storage,and seed germination showed a dormancy cycle.Seed germination of H.elliptica was not controlled by the contents of promoters or inhibitors.Seed germination correlated positively with the content of GAs and negatively with the content of IAA,while the germination percentage would be higher only when the CTK content was higher.Therefore,the relationships among endogenous hormones in this study might be consistent with the ＂three-factor＂hypothesis proposed by Khan,that is,CTK antagonized ABA,to relieve or eliminate the role of ABA and promote the role of GAs.