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Intimate Association between the Generative Cell and Endoplasmic Reticulum during the In vitro Lag Period of Magnolia x Soulangeana Pollen Germination
A. M. Dinis and J. F. Mesquita
International Journal of Plant Sciences
Vol. 155, No. 2 (Mar., 1994), pp. 158-166
Published by: The University of Chicago Press
Stable URL: http://www.jstor.org/stable/2995559
Page Count: 9
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During the in vitro lag period of Magnolia x soulangeana pollen germination, a conspicuous intimate association is established between the inner plasma membrane of the vegetative cell (VC) and the cisternae of the rough endoplasmic reticulum (RER) existing in the VC cytoplasm around the generative cell (GC). The cisternae run parallel and are tightly appressed to the inner plasma membrane of the VC without space between them. The same single cisterna often parallels the convoluted outline of the GC surface over an extensive length, almost completely covering it with RER. Possibly, the attachment of RER cisternae to the inner plasma membrane of the VC, apart from providing local synthesis, may have a role in (1) canalizing products from elsewhere in the VC cytoplasm toward the GC or (2) shielding the GC from events occurring in the VC cytoplasm. During this period the GC and the vegetative cell nucleus (VN) are always closely associated with each other, forming the male germ unit. Examination of thin sections indicates that they are probably interlocked with one another, the distance between the inner plasma membrane of the VC and the nuclear envelope of the VN being 50-70 nm in some regions. Although components that could link both the structures of the GC and VN are not detected, it is noteworthy that cisternae covering the inner plasma membrane of the VC do not normally exist in the regions where the GC is more closely associated with the VN. The possibility that this lack of cisternae is connected with the relationship between the GC and VN is discussed.
International Journal of Plant Sciences © 1994 The University of Chicago Press