楸树的开花生物学及繁育系统研究

Flower Phenology and Breeding System of Catalpa bungei(Bignoniaceae)

本文对楸树的开花习性进行观察记录,从花粉生活力、柱头可授性及套袋实验等方面对楸树的传粉机制进行研究。结果表明,楸树为典型的雌雄同花植物,花冠张开后,雌蕊柱头二裂开始张开,具有可授性,且张开120°时可授性最强;雌蕊柱头在张开期间具有较高生活力,花冠脱落后生活力开始下降,楸树单花花粉量大,可达9.4×106;楸树自交不亲和,不存在无融合生殖现象,且人工异花授粉坐果率高达94%。通过对楸树花器官的形态学及传粉的研究,为楸树的繁殖效率及其杂交育种研究奠定基础。

The flowering habits of Catalpa bungei was observed and recorded, a series of experiments including pollen vitality, stigma receptivity and bagging treatment were conducted to investigate the pollination mechanism.The results showed that C. bungei was a typical hermaphroditic plant. When the corolla opened, stigma began opening with some receptivity, and the highest receptivity was observed in an opening angle of 120 degree. Pollen kept a relatively high level during the period of stigma opening, while declined in corolla abscission period. The pollen quantity in single flower of C. bungei was colossal, could reach up to 9.4 ×106. Bagging experiments indicated that C. bungei was self-incompatible with an average fruit setting rate of 94% in artificial cross-pollination treatment, and no apomixis phenomenon was observed. The morphology and pollination biology research of C.bungei could lay a fundation for further study on improving breeding efficiency and cross breeding.