外源赤霉素信号对甘蔗分蘖及其内源激素的影响

前期研究发现,外源GA信号影响了甘蔗分蘖进程。为了解GA信号对甘蔗不同分蘖时期叶片内源激素含量的影响,以综合性状优良的甘蔗主栽品种‘桂糖42号’为材料,采用不同外源GA信号调节剂对蔗种进行浸种处理,并以清水处理为对照（CK）,分别测定分蘖初期、盛期和末期+1叶（主苗+分蘖苗）中内源激素吲哚乙酸（indole-3-acetic acid,IAA）、赤霉素（gibberellins,GA）、乙烯（ethylene,ETH）、细胞分裂素（cytokinin,CTK）、脱落酸（abscisic acid,ABA）和油菜素内脂（brassinosteroids, BR）的含量,并分析它们之间的相关关系。结果表明：外源GA₃（gibberellic acid 3;GA生物合成促进剂）对蔗种浸种处理后,增加了分蘖期甘蔗分蘖叶片中IAA、GA和CTK的总体含量,提高了分蘖前期ETH含量和后期ABA含量;多效唑（paclobutracol, PP₃₃₃;GA生物合成抑制剂）处理后却增加了分蘖前期内源GA和ABA含量,提高了后期分蘖叶片中ETH含量,同时降低了CTK和BR含量。进一步的相关性分析发现,利用外源赤霉素信号促进剂处理蔗种后,甘蔗叶片内源激素IAA与GA、CTK和BR、CTK与GA均呈显著正相关;而ABA与GA呈显著负相关,与ETH呈显著正相关。可见,外源GA信号影响了甘蔗分蘖期叶片内源激素系统,促进生长的激素与抑制生长的激素达到动态平衡状态,最终导致了甘蔗分蘖的差异。甘蔗分蘖与植物内源激素含量密切相关,可通过施用外源激素来影响内源激素的含量,调控激素之间的动态平衡,达到提高甘蔗分蘖形成及其成茎的目的。

Effect of Exogenous Gibberellin Signal on Sugarcane Tillering and Its Endogenous Hormones

Previous studies found that the exogenous GA signal affected sugarcane tillering process. In order to understand the effect of GA signal on the content of endogenous hormones in leaves at different time of tillering stage of sugarcane, this experiment used the main sugarcane variety ‘Guitang 42’ with excellent comprehensive traits as the plant material, and different exogenous GA signal regulators were used to soak the seedcanes with water treatment as the control (CK). The endogenous hormones indole-3-acetic acid (IAA) and gibberellins (GA), ethylene (ETH), cytokinin (CTK), abscisic acid (ABA) and brassinosteroids (BR) content in +1 leaves (main seedling + tiller seedling) at the early, full and late tillering stages were analyzed and the correlations between them were statistically tested. The results showed that after soaking sugarcane seedcanes with exogenous GA₃ (Gibberellic acid 3; GA biosynthesis promoter), the total contents of IAA, GA and CTK in the tiller leaves was increased at the tillering stage, and the ETH content at the early stage and the ABA content at late tillering stage were increased. Paclobutracol (Paclobutracol, PP₃₃₃; GA biosynthesis inhibitor) treatment increased the endogenous GA and ABA contents before tillering, and the ETH content at the later tiller leaves, but reduced the CTK and BR contents. Further correlation analysis found that in the treatment with exogenous gibberellin signal enhancer, the endogenous hormones of sugarcane leaves IAA and GA, CTK and BR, CTK and GA showed a significant positive correlation while ABA showed a significant negative correlation with GA but a significant positive correlation with ETH. The exogenous GA signal affected the endogenous hormone system in the leaves of sugarcane at the tillering stage, and the growth-promoting hormones and the growth-inhibiting hormones reached a dynamic equilibrium state, which ultimately led to the difference in the tillering. It is concluded that sugarcane tillering is closely related to the contents of plant endogenous hormones. Exogenous hormones could be used to influence the contents of endogenous hormones, regulate the dynamic balance between hormones, and achieve the purpose of improving sugarcane tiller formation and its stem formation.