1年生泡桐不同部位顶芽内源激素的动态变化

在河南省郑州市以1年生毛白33泡桐为试验材料,利用间接酶联免疫吸附测定法(ELISA)测定梢枝顶芽、上部侧枝、中部侧枝和下部侧枝的顶芽内源激素含量动态变化。结果表明:1)梢枝顶芽、上部侧枝顶芽、中部侧枝顶芽及下部侧枝顶芽IAA的变化趋势一致,变化趋势为"降低-升高-降低",只是上部侧枝顶芽IAA升高后降低的趋势可能会推迟;2)梢枝顶芽、上部侧枝顶芽和下部侧枝顶芽GA3含量变化趋势基本相同,均呈现出"上升-下降-上升-下降"的"双峰"形;而中部侧枝顶芽GA3含量呈现出"下降-上升-下降"的趋势;3)不同部位顶芽ABA含量均是先升高,之后下降,最后在较低水平上趋于稳定状态;4)泡桐不同部位顶芽ZR含量随时间的变化呈现出不同趋势,但总体呈下降趋势,且不同部位顶芽间存在着竞争关系及抑制作用;5)8月15日—9月15日,IAA,GA3,ZR,ABA及(IAA+GA3+ZR)/ABA比值均呈下降趋势,表明促进生长类激素与导入休眠类激素均较低,泡桐顶芽和其他邻近组织相比其竞争优势在逐渐丧失,内源激素的动态平衡被打破。本研究结果初步探明顶芽死亡与内源激素的关联性,为进一步探讨泡桐死亡机理奠定基础。

Dynamic Changes of Endogenous Hormones in Terminal Buds from Different Crown Position of One-Year-Old Paulownia

In order to probe the relationship between terminal bud death and endogenous hormones in Paulownia,ELISA was adopted to measure the content changes of endogenous hormones in the terminal buds from top shoots,the upper lateral branches,the middle lateral branches and the lower lateral branches of one-year-old P. tomentosa × P. fortunei ‘33’. The results are as follows: 1) IAA in all different terminal buds had similar change trend of "drop-rise-drop", with only except for what IAA in terminal bud from upper lateral branch delayed to decline after reaching its peak; 2) The change of GA 3 content of terminal buds from top shoots,the upper lateral branches and the lower lateral branches showed a basically same trend,namely,"rise-drop-rise-drop"with two peaks; but GA 3 content from the middle lateral branches presented a " drop-rise-drop"; 3 ) The changes of ABA content from all different terminal buds elevated at first,then reduced and finally stabilized in the low level; 4) The changes of ZR content from different terminal buds showed different trends,with an overall downward trend. There existed competition relations and inhibition among terminal buds from different branches positions; 5) From Aug-15 to Sept-15,IAA,GA3,ZR,ABA and ( IAA + GA 3 + ZR) / ABA presented a downward trend,which indicated that the hormones of growth promotion and dormancy induction were lower. The terminal bud had no competitive advantage compared with other adjacent tissue,and the dynamic balance of endogenous hormones was broken. This study illustrated a clear relationship between terminal bud death and endogenous hormones in Paulownia,and laid a foundation for further study of the terminal bud death mechanism in Paulownia.