内源激素与地被菊匍匐生长特性形成的关系研究

目的]研究内源激素与地被菊(Dendranthema morifolium cv.‘Yuhuajinhua’)匍匐生长特性形成的关系,为进一步揭示地被菊匍匐生长特性的形成提供激素生理学依据。方法]以匍匐型地被菊雨花金华为试材,采用ELISA法,测定了植株匍匐生长前后各节间茎及其匍匐茎向重性反应过程中内源激素的含量和分布。结果]内源激素在雨花金华茎负向重力侧和正向重力侧中分布具有不均匀性,且这种分布梯度在植株匍匐生长前后发生了明显改变。匍匐生长前,第3节间(发生弯曲生长的部位)负向重力侧中IAA含量显著高于正向重力侧,为正向重力侧的1.6倍;匍匐生长后,二者无显著差异。GA3在匍匐生长前茎的负向重力侧和正向重力侧中含量无显著差异,匍匐生长后,茎负向重力侧中的含量显著低于正向重力侧。而iPAs的分布在匍匐生长前后无明显变化。重力处理3 h后,匍匐茎发生明显向重性弯曲之前,IAA、GA3和iPAs的分布梯度均显著高于重力处理之前,分别是正向重力侧的1.8、1.3和1.8倍。随着重力处理的延长,其分布差异逐渐降低。由此推测,内源激素在雨花金华茎中的不对称分布与其匍匐生长特性的形成有着密切关系,很可能是茎生长到6～7个节位大小时,感受重力刺激后,内源激素在茎的向重性反应部位(顶芽下第3节间)形成了一定的分布梯度,更多的IAA和GA3分布在茎的负向重力侧,从而使茎负向重力侧生长快于正向重力侧,导致茎发生横向重性弯曲生长;当茎弯曲生长后,茎的负向重力侧和正向重力侧中的激素分布梯度差异减小,使得茎得以保持匍匐生长。结论]生长素的含量和分布对植物株型建成具有重要作用。

Study on Relationship between the Endogenous Phytohormone and the Creeping Formation in Creeping Ground-cover Chrysanthemum(Dendranthema morifolium cv. ’Yuhuajinhua’)

Objective] The essay aimed to study the relationship between the endogenous phytohormone and the creeping formation in creeping ground-cover chrysanthemum,and provide a phytohormone physiological basis for deeply revealing its creeping formation mechanism.Method] The content and distribution of endogenous phytohormone in the different internodes of chrysanthemum were detected by ELISA before and after shoot creeping,also in the gravitropical bending stem.Result] The results showed that there was asymmetric distribution of phytohormone in the upper and lower side of the stem,which changed before and after stem creeping.Before creeping,the content of IAA in upper side of the third internode,where the stem curved,was 1.6 times to that in the lower side;but after creeping,there was no significant difference between them.GA3 was the same as IAA before stem creeping;but its content in the upper side became lower than the lower side after creeping.There was no difference in the content and distribution of iPAs before and after creeping.It was discovered that creeping stem’s IAA,GA3 and iPAs contents after 3 h gravistimulation and before bending to the gravity obviously were significant higher than those before gravistimulation,and was 1.8,1.3 and 1.8 times of the lower side.But this distribution difference decreased gradually with prolonging of gravistimulation time.So the unsymmetrical distribution of endogenous phytohormone in ’Yuhuajinhua’ stems had a close relationship with its creeping stem growth character.It was likely that endogenous phytohormone in stems formed a certain distribution gradient after experiencing the gravistimulation when stems had 6-7 sections,and the asymmetric distribution of IAA and GA3 leaded asymmetrical growth of the upper and lower side of the stem after experiencing the gravistimulation,which caused the bending growth.When the stem become growing in creeping,the distribution gradient was shorten so as to keep the creeping growth.Conclusion] The phytohormone content and distribution has an important role in formation of plant types.