A23187和EGTA对光周期诱导菊花成花及其过程中叶片Ca^(2+)分布和碳水化合物的影响

Effects of Ca^(2+)-carrier A23187 and Ca^(2+)-chelator EGTA on the flower formation of chrysanthemum under photoperiodic induction and the Ca^(2+) distribution and carbohydrate contents in leaves during the flower formation

以切花菊品种‘神马’为试材,研究光周期诱导菊花成花过程中Ca2+载体A23187和Ca2+螯合剂EGTA处理对花芽分化及其过程中叶片Ca2+分布和蔗糖、可溶性糖及淀粉含量变化的影响.结果表明:对照叶片Ca2+含量在花芽未分化期(Ⅰ)处于较低水平,而在花芽分化启动期(Ⅱ)迅速增加并达到高峰,之后下降;Ca2+亚细胞定位表明,在未分化期(Ⅰ)Ca2+沉淀主要分布在液泡、细胞壁和细胞间隙中,细胞质内较少,而在花芽分化启动期(Ⅱ)细胞质内积累大量的Ca2+沉淀.A23187处理的菊花花芽分化开始和结束时间比对照分别提前2d和3d,叶片Ca2+含量比对照显著增加;EGTA处理的叶片Ca2+含量比对照显著减少,花芽分化开始和结束时间分别比对照推迟4d和8d;A23187和EGTA处理的叶片Ca2+在花芽分化启动期(Ⅱ)均向细胞质流入并密集.A23187处理的蔗糖和可溶性糖含量在处理2d时达到峰值,比对照达到峰值的时间提前2d,与Ca2+达到峰值的时间一致,而EGTA处理的蔗糖和可溶性糖含量在处理2d时没有明显变化,8d时才迅速增加达到峰值,即所有处理的蔗糖、可溶性总糖含量在花芽分化启动期(Ⅱ)均增加并达到高峰,之后有所减少,但其在整个花芽分化过程均高于光周期诱导前的含量;对照和A23187处理的淀粉含量在处理2d时开始减少,而EGTA则在处理8d后开始减少,至花芽分化结束所有处理的淀粉含量均保持较低水平(低于诱导前).表明Ca2+和碳水化合物参与了光周期诱导的菊花成花过程.

This paper studied the effects of Ca^2＋-carrier A23187 and Ca^2＋-chelator EGTA on the bud differentiation of cut flower chrysanthemum （Dendranthema grandiflorium ‘Shenma’） under photoperiodic induction, as well as the Ca^2＋ distribution and the sucrose, soluble sugar, and starch contents in ‘Shenma’ leaves during the differentiation. In the control, the leaf Ca^2＋ content was lower at the vegetative stage of apical bud （Ⅰ）, increased rapidly and reached a peak at the stage of initial differentiation （Ⅱ）, and decreased then. At stage Ⅰ, the Ca^2＋ was mainly allocated in vacuole, cell wall, and cell lacuna; while at stage Ⅱ, it was more in cytoplasm. Compared with the control, the leaf Ca^2＋ content of A23187-treated plants increased significantly, and the days of initiation and ending of bud differentiation were advanced by 2 days and 3 days, respectively. On the other hand, the leaf Ca^2＋ content of EGTA-treated plants decreased significantly, and the days of initiation and ending of bud differentiation were postponed by 4 days and 8 days, respectively. For both A23187- and EGTA-treated plants, their leaf Ca^2＋ at stage Ⅱ was more allocated in cytoplasm. The leaf sucrose and soluble sugar contents of A23187-treated plants reached a peak on the 2nd day after treatment, and the time to reach the peak was shortened by 2 days, compared with the control, which was consistent with the peak time of Ca^2＋. The leaf sucrose and soluble sugar contents of EGTA-treated plants had no significant changes on the 2nd day of treatment, but increased rapidly and reached the peak on the 8th day of treatment （stage Ⅱ）, and then decreased. However, the leaf sucrose and soluble sugar contents during the whole period of bud differentiation were higher than those before photoperiodic induction. The leaf starch content of A23187-treated plants and the control decreased 2 days after treatment, while that of EGTA-treated plants began to decrease 8 days after treatment, and maintained at a lower level by the end of bud differentiation. The results indicated that Ca^2＋ and carbohydrates participated in the flower formation of chrysanthemum under photoperiodic induction.