Relationship between floral bud differentiation and endogenous hormones in autumn-cutting chrysanthemum morifolium ‘jinba’ | 切花秋菊‘神马’花芽分化与内源激素的关系

Chinese. 【目的】研究短日处理下菊花（Chrysanthemum morifolium）花芽分化与内源激素的关系。【方法】以切花秋菊‘神马’为试材,通过对短日处理下花芽的形态解剖观察及顶芽和叶片中内源激素的测定,研究花芽分化过程中内源激素的动态变化。【结果】花芽分化过程中顶芽中GA3含量下降且大多时期保持在较低水平,叶片中GA3变化与之相反;顶芽中IAA含量先下降,在小花原基分化初期达到最小值,到花冠形成中期达到最大,叶片内源IAA含量在总苞鳞片分化初期前呈上升趋势,随后逐渐下降,到花冠形成期趋于平稳;内源CTK含量大幅增加,均高于未分化期;顶芽中ABA含量先下降,后期呈现上升趋势,叶片中ABA含量变化与顶芽相反,呈现先积累,经短暂平稳期后逐渐减少的趋势。花芽分化开始后CTK/IAA、CTK/GA3、ABA/IAA和ABA/GA3的比值均增大。【结论】高水平的CTK和ABA与菊花花芽分化相关联。在花芽分化初期,顶芽中低浓度IAA、GA3,以及叶片中高含量的IAA、GA3关系到菊花由营养生长向生殖生长转变;在花芽分化后期,顶芽中GA3和IAA的积累关系到花冠形成。从激素平衡来看,维持高比率的CTK/IAA、CTK/GA3、ABA/IAA和ABA/GA3有利于菊花的花芽形成。

English. 【Objective】The relationship between floral bud differentiation and endogenous hormones in chrysanthemum (Chrysanthemum morifolium) was studied. 【Method】 The autumn-cutting chrysanthemum ‘Jinba’ was short-day treated, and the dynamic changes of endogenous hormones during floral bud differentiation were studied after measuring the morphological anatomies in flower bud and the endogenous hormones in apical bud and leaves. 【Result】 The results showed that GA3 contents in apical bud decreased and stayed at a low level in most of the time, however, the changes of GA3 contents in leaf were the contrary to the apical bud. The IAA contents in apical bud decreased first and reached the minimum value at the initial stage of floret primordia differentiation, and then reached the maximum value at the metaphase stage of crown formation. The IAA contents in leaf showed an increasing tendency before the initial stage of involucre primordia differentiation, then decreased later, and changed to be steady until the stage of crown formation. The contents of CTK increased greatly and were higher than those at the vegetative stage. The ABA contents in apical bud decreased first and then showed an increasing tendency, while ABA contents in leaves increased first and showed a decreasing tendency after a short steady period. The ratios of CTK to IAA, CTK to GA3, ABA to IAA and ABA to GA3 increased after flower bud differentiation started. 【Conclusion】 The research results showed that increasing in contents of CTK and ABA was related with floral bud differentiation of chrysanthemum. At early stage of flower differentiation, decreasing in contents of IAA and GA3 in apical bud and increasing in contents of IAA and GA3 in leaves were related to converting from vegetative growth to reproductive growth, while accumulating in contents of GA3 and IAA in apical bud was related to crown formation at final stage of flower differentiation. As to the hormones balance, maintaining high ratios of CTK to IAA, CTK to GA3, ABA to IAA and ABA to GA3 were beneficial to flower bud formation.