大白杜鹃与露珠杜鹃杂交亲和性及其杂交果实发育动态研究

The Compatibility and Fruit Growth Dynamics of the Cross between Rhododendron decorum and R. irroratum

以大白杜鹃为母本,露珠杜鹃为父本进行杂交试验,通过测算露珠杜鹃与大白杜鹃的花柱长度比进行杂交可行性分析,利用荧光显微镜观察授粉后露珠杜鹃花粉管的生长状况确定杂交亲和性,并对温室和露天两种条件下的杂交果实的纵横径动态变化情况进行观测。研究结果显示,露珠杜鹃与大白杜鹃的花柱长度比为0.98,推测两种杜鹃杂交容易成功。露珠杜鹃花粉管在授粉后9 d进入大白杜鹃胚珠并完成受精,证实两种杜鹃杂交亲和。温室和露天条件下的杂交果实形态成熟时间均约180 d,其中,授粉后0~9 d为第1次缓慢生长期,授粉后9~105 d为第1次迅速生长期,授粉后105~135 d为第2次缓慢生长期,授粉后135~180 d为第2次迅速生长期;果实纵径和横径的生长动态变化过程相似,但横径的生长动态曲线较纵径平缓。温室条件下的杂交果实纵横径大小明显高于露天条件下的杂交果实。研究认为,大白杜鹃与露珠杜鹃杂交亲和,杂交果实生长动态曲线为＂双S＂型,其形态成熟时的纵横径大小与其栽培条件直接相关。

The cross between Rhododendron decorum and R. irroratum was conducted. Its cross feasibility was analysed by measuring the ratio of male style length of R. irroratum to the female style length of R. decorum.Fluorescence microscope was used to study the process of pollen sprouting and pollen tube growth of R. irroratum after crossing to ensure the cross compatibility. The hybrid fruit growth dynamics of the crosses were observed and analyzed at different development stages after pollination under the conditions of greenhouse and outdoors separately,the results showed as follows,the ratio of male style length of R. irroratum to the female style length of R. decorum was 0.98 which indicated that the cross between R. decorum and R. irroratum inclined to success.The cross compatibility was proved by the fact that the pollen tube of R. irroratum entered the ovules of R. decorum and then the fertilization happened at 9d after pollination according to the observation of Fluorescence microscope.The morphological mature period of both the hybrid fruits under two separate cultivation conditions was about 180 d,in which,after pollination,0- 9 d was the first slow growth period,9- 105 d was the first fast growth period,105-135 d was the second slow growth period and 135-180 d was the second fast growth period.The growth dynamic changes of the vertical and horizontal diameters of the fruit were similar but the dynamic growth curve of horizontal diameter was gentler than that of the vertical diameter. The results indicated that the cross between Rhododendron decorum and R. irroratum was compatible and the hybrid fruit growth curve belonged to the double ＂S＂curve. Moreover,the size of the vertical and horizontal diameters of the hybrid fruit at the morphological mature time was directly related to the cultivation conditions.