Orchid Embryology: The Membrane Systems and the Pollen Tube Growth

SUMMARYThe electron dense bodies associated with the tonoplast of the vegetative cell prior germination of the pollen grain are considered as the precursors of intravacuolar concentric membranous bodies (ICMB). Such bodies are postulated as the main structures involved in the tonoplast extension during the first phase of the pollen tube growth; they may also be engaged, in a similar manner with the plasmalemma. A tentative functional model is proposed.