Elektronenmikroskopische Beobachtungen an der vegetativen Zelle im auskeimenden Pollenkorn von Oenothera hookeri Torr. et Grey

Abstract

According to the intense activity of the vegetative cell in the germinating pollen grain, the cytoplasm shows a highly organized structure. Concerning the structure the vegetative cell differs strongly from the generative cell. In the vegetative cell the big nucleus shows a very lobed shape. Large invaginations of the cytoplasm into the nucleus can be frequently observed. Series of adjacent sections show that deep and flat vesicles which may often broaden to unusual large cisternae, extend through the vegetative plasm and form by interconnections a highly developed endoplasmic reticulum which is continuous with the nuclear envelope. The leucoplasts contain large starch grains and very few lamellae, in many sections only one lamella is visible. Sometimes, a process of a leucoplast deeply reaches into another leucoplast. In some leucoplasts and mitochondria there are concentric stripes which, according to serial sections, are the margins of invaginations of the cytoplasm or of another organell. In the numerous mitochondria the inner folds have the form of cristae, tubules are not so frequently seen. The edges of the flattened sacs of the Golgi - apparatus expand to vacuoles which seem to separate from the flattened cisternae. Typical for the vegetative plasm are numerous small vacuoles. Relatively large, ringshaped or uniform dark bodies are assumed to be lipid inclusions.