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Division of the Generative Cell and Late Development in the Male Gametophyte of Ginkgo biloba
William E. Friedman and Ernest M. Gifford
American Journal of Botany
Vol. 75, No. 9 (Sep., 1988), pp. 1434-1442
Published by: Botanical Society of America, Inc.
Stable URL: http://www.jstor.org/stable/2444465
Page Count: 9
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Division of the generative cell in the male gametophyte of Ginkgo biloba to yield the sterile cell and spermatogenous cell was examined in vivo and in vitro. Evidence is presented in support of a new interpretation of development in which the sterile cell and spermatogenous cell arise from an unusual anticlinal ringlike division of the generative cell. This type of cell division is only known to occur during antheridial development in leptosporangiate ferns and stomatal development among certain ferns in the Schizaeaceae and Polypodiaceae. The strong similarities in development and cell arrangement within the male gametophytes of cycads and Ginkgo suggest that division of the generative cell in cycads may be the same as in Ginkgo. Although the ringlike (conically annular) divisions in the antheridia of leptosporangiate ferns and the male gametophytes of Ginkgo (and probably cycads) are remarkably similar and result in the production of a central spermatogenous cell, it is conjectural as to whether these patterns represent a striking convergence or evolutionary homology.
American Journal of Botany © 1988 Botanical Society of America, Inc.