© 1997 Walt Dineen Society

Walt Dineen Society Annual Conference '97

Session I: Upland Plants Abstract #: 97105


David W. Lee
Department of Biological Sciences, Florida International University,
University Park, Miami, Florida 33199


Leaves frequently develop red coloration during development, at maturity, and during senescence. Most plants produce anthocyanins (usually cyanidin glucosides) as the basis of this color, but members of the Caryophyllales (as Pisonia, in the Nyctaginaceae) produce nitrogenous pigments, betacyanins. Hypotheses about the function of this coloration have been hampered by the lack of experimental data as well as poor knowledge of the taxonomic and tissue distribution of these pigments in leaves. I have initiated a broad comparative survey and here report on results from 98 species native to the Everglades. 44 species (41.8 % of the total) produced anthocyanins, and one species, Pisonia aculeata, produced betacyanin. 24 taxa produced anthocyanins early in development, 5 taxa during senescence, and 9 taxa produced anthocyanins at both stages. Three taxa, all aquatic, produced anthocyanins in the lower epidermis of mature leaves. Most taxa produced pigmentation in the mesophyll tissue (usually in the palisade), inconsistent with the traditional hypothesis of protection against UV-B. Of those taxa producing anthocyanins in development and senescence, most retain a single tissue location (usually the palisade), but some taxa are developmentally plastic. A broader survey will facilitate a phylogenetically weighted analysis, and more direct studies will benefit from species that are polymorphic for such coloration, as Chrysobalanus icaco.


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