打顶对棉花赘芽生长的影响及其激素调控

以赘芽生长势强的冀151和269系及赘芽生长势弱的冀棉169和182系作为材料,观察打顶(D)、打顶+顶施IAA(D+T)和打顶+果枝顶芽施用IAA(D+F)处理下赘芽的生长势以及内源Z+ZR与IAA含量的变化。结果显示,棉花上部赘芽在打顶20 d后显著伸长,内源Z+ZR水平在打顶6 h后也明显提高,IAA水平显著下降;而D+T和D+F处理的棉花上部赘芽的伸长及内源Z+ZR水平的提高幅度均明显低于D处理,IAA含量则无显著变化。表明棉花茎节处合成的CTK促进赘芽生长,其水平受茎中由上而下IAA流的控制。棉花赘芽的生长既受主茎中IAA流调控,也受果枝中IAA流的影响。

Effects of Decapitating on Cotton Redundant Vegetative Shoots Growth and Hormonal Regulation Mechanism

Varieties (lines) with stronger growth vigor of redundant vegetative shoots, Ji 151 and 269 line, and weaker ones, Jimian 169 and 182 line, were treated with decapitation (D treatment), decapitation + stump application of IAA in lanolin (D+T treatment) and decapitation + application of IAA in lanolin on tops of fruit branches (D+F treatment). The growth of redundant vegetative shoots as well as concentrations of endogenesis Z+ZR and IAA were investigated. It was shown that redundant vegetative shoots on upper nodes significantly elongated in 20 days after being decapitated, also increasing Z+ZR level and decreasing IAA level were detected at 6 h after decapitation. But in D+T and D+F treatments, the total length of redundant vegetative shoots and endogenesis Z+ZR levels were observably lower than those in D treatments, respectively, and the IAA concentrations were equal to that before being decapitated. These indicated that, the growth of redundant vegetative shoots was promoted by CTK synthesizing in nodes, whose concentration was controlled by basipetal IAA flow both in the main stem and in the fruit branches.