几种柑橘属植物花粉外壁超微结构比较研究

A Comparative Study on Pollen Exine Ultrastructure of Several Citrus

应用超薄切片技术,在透射电镜下对几种柑橘属植物花粉外壁的超微结构进行了观察,结果表明,柑橘属植物花粉具4～5孔沟,外壁内层发育好,花粉外壁结构属于较进化类型。供试材料花粉外壁超微结构特征各异,说明了柑橘属植物的遗传多样性;野生柑橘花粉外壁柱状层为颗粒结构,栽培柑橘为小柱结构,似可说明柑橘花粉外壁柱状层的进化趋势是由颗粒结构到小柱结构。莽山野柑和莽山野橘花粉外壁超微结构存在明显差异,主要表现为:莽山野柑花粉外壁的柱状层发育差,为颗粒状,覆盖层厚度为0.41μm,内层厚度为0.84μm;莽山野橘花粉外壁的柱状层发育好,为小柱状,覆盖层厚度为0.47μm,内层厚度为0.33μm。据此认为柑应有种的地位。

The pollen exine ultrastructure of several citrus plants was examined by using ultrathinned sectioning technique under transmission electron microscope.Results showed that the pollen grains of the citrus have4～5colporates,thicker endoexine.The pollen exine ultrastructure is different from each other,which specifies the genetic diversification of citrus.The pollen exine of wild citrus possesses granular bacules,and that of cultivated citrus possesses columellae.It may be concluded that the developed tendency of the pollen exine of citrus goes from the granular bacule to columellate.The pollen exine of Mangshan Ye Gan(a kind of wild citrus)is different from that of Mangshan Ye Ju(a kind of wild citrus).The pollen exine of Mangshan Ye Gan possesses granular bacules,with a tectum of thickness of0.41μm and an endoexine of thickness of0.81μm;The pollen exine of Mangshan Ye Ju possesses columellate with a tectum of thickness of0.47μm and an endoex-ine of thickness of0.33μm.This paper classifies the Gan as a category of species.