GORELICK, ROOT1* and ROY OSBORNE2. 1Department of Biology, Arizona State University, Tempe, AZ 85287-1501, U.S.A.; 2P.O. Box 244, Burpengary, Queensland 4505, Australia. - Inducing sex change and organogenesis from tissue culture in the endangered African cycad Encephalartos woodii (Cycadales, Zamiaceae).
We propose a radically new approach to sex change of plants - via
demethylation and methylation of chromosomal DNA - based on nascent
theoretical work on evolution of sex determination in all plants and
animals. This approach should not only result in sex change, but also
in mutations (thereby increasing genetic variation) and regeneratation
of whole plants from tissue-cultured cells. This should result in
propagation of many viable and genetically variable individuals of
both sexes with the desired parenthood of mitochondrial and
chloroplast DNA. Thus, remarkably, artificially induced demethylation
and methylation of chromosomal DNA may allow for the re-establishment
of viable populations of plants from a single clone of a dioecious
species. We propose testing and applying this theory to conservation
of the cycad Encephalartos woodii, for which only a single male
clone exists, sex change has never been induced, and roots and shoots
have never been regenerated from tissue culture callus.
Key words: azacytidine, conservation, Encephalartos woodii, epigenetic, methylation and demethylation