Vegetative Cell Nuclei Research Articles

Intimate Association between the Generative Cell and Endoplasmic Reticulum during the In vitro Lag Period of Magnolia x Soulangeana Pollen Germination

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.

RNA synthesis by vegetative and sperm nuclei of trinucleate pollen.

In binucleate pollen tubes the vegetative and generative cell nuclei are known to synthesize RNA. Nothing is known about RNA synthesis in trinucleate pollens. To determine whether RNA synthesis occurs in trinucleate pollen, Secale cereale pollen was studied. The vegetative and sperm cell nuclei of the in vitro grown pollen tubes were shown by autoradiography to incorporate [5-3H] uridine. This incorporation was interpreted as indicating the synthesis of RNA.

THE DISPOSITION OF GAMETE AND VEGETATIVE-CELL NUCLEI IN THE EXTENDING POLLEN TUBES OF A GRASS SPECIES, ALOPECURUS PRATENSIS L.

Acta Botanica NeerlandicaVolume 33, Issue 1 p. 131-134 Brief Communication THE DISPOSITION OF GAMETE AND VEGETATIVE-CELL NUCLEI IN THE EXTENDING POLLEN TUBES OF A GRASS SPECIES, ALOPECURUS PRATENSIS L. J. Heslop-Harrison, J. Heslop-Harrison Cell Physiology Laboratory, Welsh Plant Breeding Station, Plas Gogerddan, nr Aberystwyth SY23 3EB, U.K.Search for more papers by this authorY. Heslop-Harrison, Y. Heslop-Harrison Cell Physiology Laboratory, Welsh Plant Breeding Station, Plas Gogerddan, nr Aberystwyth SY23 3EB, U.K.Search for more papers by this author J. Heslop-Harrison, J. Heslop-Harrison Cell Physiology Laboratory, Welsh Plant Breeding Station, Plas Gogerddan, nr Aberystwyth SY23 3EB, U.K.Search for more papers by this authorY. Heslop-Harrison, Y. Heslop-Harrison Cell Physiology Laboratory, Welsh Plant Breeding Station, Plas Gogerddan, nr Aberystwyth SY23 3EB, U.K.Search for more papers by this author First published: February 1984 https://doi.org/10.1111/j.1438-8677.1984.tb01779.xCitations: 29AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Citing Literature Volume33, Issue1February 1984Pages 131-134 RelatedInformation

An autoradiographic study of RNA synthesis during maturation and germination of pollen grains ofHyoscyamus niger

The pattern of RNA synthesis during maturation and germination of pollen grains ofHyoscyamus niger was studied using3H-uridine autoradiography. Incorporation of label during pollen maturation was periodic with peak RNA synthesis occurring in the uninucleate, nonvacuolate pollen grains and in the vegetative cell of the bicellular pollen grains. During the early stages of germination, isotope incorporation occurred predominantly in the nucleus of the vegetative cell with little or no incorporation in the generative cell. With the appearance of the pollen tube, incorporation of3H-uridine in the vegetative cell nucleus decreased and completely disappeared at later stages of germination. No incorporation of isotope was observed in the sperms formed in the pollen tube by the division of the generative cell. From a comparison of the results of this study with those of previous works on RNA synthesis during pollen embryogenesis in cultured anthers ofH. niger, it is concluded that in contrast to embryogenic development, there is no requirement for sustained RNA synthesis by the generative cell nucleus for normal gametophytic development.

Patterns of DNA synthesis during pollen embryogenesis in henbane.

Continued DNA synthesis in the generative cell nucleus, followed by mitosis and cytokinesis, results in the formation of pollen embryoids in cultured anthers of H. niger. In contrast, the nucleus of the vegetative cell undergoes no DNA synthesis after it is cut off, or synthesizes DNA only during a limited number of cell cycles. DNA synthetic patterns in the generative and vegetative cell nuclei confirm the ontogeny of embryoids described in this plant.