Observations on Certain Plastids of the Ovule ofGinkyo BilobaL.

SUMMARYAs reported in the literature for several groups of algae and for certain cells of higher plants, among which the endosperm (CAMEFORT and SCHAEFFER 1965) and the oosphere of Ginkyo biloba L. (CAMEFORT 1965), the authors observe that there is also often a contiguity between endoplasmic reticulum and plastids in the tapetum and in the central cell of the archegonium of this plant. The functional significance of this relationships is hypothesized. Moreover, the authors note that in the central cell and in the coenocytic pro-embryo the outer membrane of the plastidial wall bears some evaginations that extend into the cytoplasm. These evaginations seem, in certain cases, to connect two plastids in the central cell, for which it is thought that their formation is due to a particular scission process of the plastids themselves.