Tropical Biology Section
Cozza, John .
Sex, lies, and begonias: Light and N affect gender in a rainforest herb, Begonia urophylla.
Since they have separate sex flowers on the same plant, monoecious plants may be able to adjust how male or female they are. In the forest at Las Cruces, Costa Rica, individual plants of the understory herb Begonia urophylla were able to adjust their phenotypic bloom gender (the proportion of flowers that were female). Gender was related to plant size and light, but the causes of gender adjustment were uncertain. In the lab, my students and I grew B. urophylla under all combinations of high and low light, high and low N, and high and low P treatments. High light and high N both caused plants to be more female in bloom gender, but P levels had no effect on gender. Under high light, matched leaves of plants grown under high N were greener than the leaves of plants grown under low N, suggesting a possible photosynthetic basis for the N effect on gender. Gender in B. urophylla, which only blooms once a year, may be largely determined by a plantís ability to capture light, and make and store photosynthate, in the marginal conditions of the forest understory.
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1 - University of Miami, Department of Biology, 1301 Memorial Drive, Coral Gables, Florida, 33124, USA
environmental sex determination
Presentation Type: Oral Paper:Papers for Sections
Location: Lake Ontario/Hilton
Date: Tuesday, July 10th, 2007
Time: 1:00 PM