Programmed Cell Death in the Development Process of Secretory Cavities of Ovule 'Gibbosity' at the Initial Stage of Ginkgo biloba var.epiphylla

Taking the common Ginkgo biloba plants as control,the development process of the ovule secretory cavities of Ginkgo biloba var.epiphylla was observed by means of resin slicing and scanning electron microscope.The results showed that there was well developed secretory structure in the ovule of Ginkgo biloba var.epiphylla,and both of the two species showed the characteristics of PCD(programmed cell death) in the development cause of the secretory cavities in the ovule.The PCD phenomenon was exhibited by the following procedure: the cell wall was disintegrated along with the formation of intercellular space;followed by the disintegration of the central secretory cells;then the neighboring cells degraded;the secretory vesicles were swallowed by adjacent phagocytic cells without inflammatory response,which showed the autophagy function before the secretory cavities were formed.The secretory cavities of both Ginkgo biloba var.epiphylla and Ginkgo biloba belonged to schizo-lysigeneous secretory cavities.