Origin and Development of the Lytic Compartment
The cytoplasmic membranes of plant cells form the boundaries of about a dozen distinct compartments. Except for the inner membranes of mitochondria and plastids, these cytomembranes are ontogenetically related, directly or indirectly, to the endoplasmic reticulum (ER). The flattened cisternae of the dictyosomes originate through the coalescence of ER-derived vesicles and vesicles which are, in turn, pinched off from dictyosomes eventually fuse with the plasmalemma. The Golgi-system and the plasmalemma are, thus, ER-homologous membranes (see Morré et al. 1971). It will be seen that the lytic compartment of plant cells is likewise bounded by ER-homologous membranes: vacuolar membranes seem to be direct products of the ER, and the plasmalemma which is indirectly related to the ER separates the cytoplasm from the external space of the lytic compartment.
KeywordsRough Endoplasmic Reticulum Golgi Complex Vacuolar Membrane Golgi Membrane External Space
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