Abstract:

The pollen grain morphology of 42 varieties of Bougainvillea was observed by using electron microscopy. Compared with the published data of the pollen sterility of Bougainvillea, the relationship between pollen grain morphology and pollen sterility was studied. We collected the pollen of the 42 cultivated species of Bougainvillea and carried out the drying and morphological observation. Pictures of pollen distal view, pollen proximal view and pollen equatorial view under 3000 times and the outer wall of the network under the 10000 times were gathered, to determine the pollen grain morphology of the 42 varieties of Bougainvillea. The size of pollen and the number of germination ditches were measured. The number of buds of different varieties of Bougainvillea and different areas of pollen were compared. It was found that the appearance morphology of Bougainvillea was convex cake structure which was unilateral depression and unilateral protruding. The pollen grains of different varieties of Bougainvillea were 21.64-31.14 μm. There were three germination ditches in a few varieties and most of the varieties had less than three germination ditches. There were a lot of reticulate folds on the surface. The number of buds on the folds was different in different varieties and the number of buds was closely related to the pollen sterility. The number of pollen surface buds of varieties with high pollen sterility was higher than that with low pollen sterility. The low number of pollen surface buds in hybrid varieties could reduce the attachment ability of pollen and cause low pollen sterility.

Key words: Bougainvillea, Pollen Morphology, Electron Microscopy, Pollen Sterility