| Abstract: | P. godefroyae is one of the diandrous species of rather primitive orchids. The cytokinesis of PMCs conforms to simultaneous type. The arrangement of microspores in a tetrad is tetrahedral or isobilateral. The first mitosis in a pollen grain is unequal and results in the formation of two unequal cells. The small one is the generative cell and the large one, the vegetative cell. The wall material between them is callose which is easily detectable under the fluorescence microscope. When the generative cell detaches from the microspore wall and migrates into the cytoplasm of the vegetative cell, the callose wall disappears and a thin PAS-positive wall Was observed around the generative cell. The PAS-positive wall remains untill anthesis. The tapetum is of secretory type and its cells are binucleate. With the degradation of the tapetal cells, they discharge a lot of yellow, amorphous, sticky mass into the pollen sac. The pollens distribute in it to form a sticky pollen mass. The ovule has single integument and one layered nucellus around the magaspore mother cell. The mature embryo sac consists of eight or six cells and conforms to the Allium type. The interval between pollination and fertilization is about 45 days and the normal double fertilization has been observed. The primary endosperm cell undergoes one division only and results in the formation of 2 nucleate endosperm. The dormancy period of zygote lasts 45–50 days. During the development of the embryo, a suspensor consisting of a row of two to four cells is formed. It takes more than six months from the pollination to the maturation of the seed. The embryo in the mature seed is just an ellipsoidal mass of 120–140 cells without differentiation. The endosperm and suspensor are all degenerated in the mature seed. |
