小苍兰开花特性与繁育系统研究

Studies on Flowering Characteristics and Breeding System of Freesia hybrida

综合运用杂交指数、花粉活力及柱头可授性、花粉/胚珠比、人工控制授粉试验等,对小苍兰的花部结构及繁育系统进行研究。结果表明:小苍兰雄蕊和雌蕊空间分离,花药紧贴花柱外侧,低于柱头约2 mm,在花朵开放的整个过程中雌、雄蕊的相对位置不变。小苍兰雌雄异熟现象明显,花药开裂时间与柱头可授期不同步,当花粉活力达到最高值时,柱头可授性还较低。小苍兰杂交指数(OCI)为5,花粉/胚珠比(P/O)为1 614,人工授粉的坐果率高于自然传粉,由此判断其交配方式是以异交为主,自交为辅,繁育系统为兼性异交。

Through the field observation and experimental study,the outcrossing index （OCI）,pollen vitality and stigma receptivity,the ratio of pollen and ovule（P/O）,artificial pollination and bagging were investigated to understand the flower structure and reproduction system in Freesia hybrida. The results showed that the stamen of Freesia hybrida was closed to the lateral side of the style and about 2 mm shorter than the stigma. The relative position between the stamen and gynoecium was unchanged during the whole flowering stage. In addition,the stamen and gynoecium of Freesia hybrida mature at different times,the highest period of receptivity stigma was not synchronized with the peak stage of pollen viability. The OCI and P/O are 5 and 1 614,respectively. Taking the results of the artificial pollination experiment together,it indicated that reproduction system of Freesia hybrida was facultative outcrossing with outcrossing as the main breeding form and self-pollination as auxiliary form. Artificial pollination on fruit set rate was higher than the natural pollination.