Bryological and Lichenological Section/ABLS
d'Artenay, Tamrya D. , Mishler, Brent D. .
Reproductive Studies of the Moss Calymperes graeffeanum from Moorea, French Polynesia.
IN recent years, numerous studies have been performed on moss reproduction, most focusing on sexual reproduction, but few from tropical regions or islands. This study focuses on sex ratios and possible trade-offs between asexual and sexual propagation in Calymperes graeffeanum. 60 colonies were collected along transects on the island of Moorea, French Polynesia. A sample of one stem/cm2 was taken from each colony and the number of propagulous leaves and total leaves were counted. Colony densities were calculated, and distance from fertilized females to the nearest male were measured. It was found that individuals lacking either male or female inflorescences had a higher degree of asexual reproduction than those expressing sex. Individuals with a higher number of inflorescences had a lower proportion of propagulous leaves. Age also played a role in asexual reproduction; older individuals tended to produce a higher proportion of propagulous leaves. Males tended to have a higher proportion of propagulous leaves than females. The mean distance between fertilized females and the nearest male was 1.63 cm, indicating a short gamete dispersal distance. Finally, density does not appear to play a role in the expression of sex or sporangia number for this species. Carlquist’s concept of the “island syndrome”, wherein island plants are expected to evolve a shorter dispersal distance and a decrease in sexual reproduction, may help explain these results. Alternatively, the environment may be responsible for the scarcity of male plants (or at least male expression), prohibiting male propagules from germinating or adults from expressing sex.
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1 - University of California, Berkeley, Department of Integrative Biology, University and Jepson Herbaria, 1001 Valley Life Sciences Bldg. #2465, Berkeley, California, 94720, USA
2 - University of California, Berkeley, Department of Integrative Biology, 1001 Valley Life Sciences Bldg. #2465, Berkeley, California, 94720-2465, USA
Presentation Type: Oral Paper:Papers for Sections
Location: 304/Bell Memorial Union
Date: Monday, July 31st, 2006
Time: 3:30 PM