Elektronenmikroskopische Beobachtungen an der generativen Zelle von Oenothera hookeri Torr. et Gray

In the germinating pollen grain the generative cell shows the structure of a meristematic cell. It is separated from the cytoplasm of the vegetative cell by a clearly visible wall, on the average about 30 — 60 mµ thick. This wall appears to be formed by two darkly stained membranes including a lighter region of varying thickness. In the generative cell there are a big nucleus, plastids which show a scarcely developed lamellar system but no starch grains, mitochondria, dictyosomes. very probably lipid bodies and unidentified cytoplasmic inclusion bodies. The endoplasmic reticulum is continuous with the membranes of the nuclear encelope and extends through the cytoplasmic substance in which no vacuoles are recognizable.