Abstract Detail

Reproductive biology

Christopher, Dorothy [1], Chang, Shumei [2].

Sex allocation in hermaphrodites of the gynodioecious Geranium maculatum.

Dioecy has arisen independently in the angiosperms many times. Understanding how separate male and female sexes have evolved is therefore an important question in plant biology. The theory to receive the most support suggests that dioecy evolves from hermaphroditism through a gynodioecious intermediate stage; the presence of females puts selective pressure on hermaphrodites to increase male function at the expense of female function. We tested this prediction in the gynodioecious Geranium maculatum. In ten populations that ranged from 0-35% female, we measured floral traits important for male and female function to examine whether the sex allocation of hermaphrodites changes with the population sex ratio. We found that hermaphrodites in high female frequency populations do not increase allocation to male traits; flower production and pollen counts did not differ between populations. However, hermaphrodites in high female frequency populations had fewer flowers set fruit than hermaphrodites in hermaphrodite-only populations. This might suggest that hermaphrodites are reducing allocation to female function when females are present. Future work will incorporate the effect of spatial structuring of the sexes within populations, as well as analyze the patterns of direct selection on floral traits.

1 - University of Georgia, Plant Biology, 2502 Miller Plant Sciences, 120 Carlton St , Athens, GA, 30602, USA
2 - University Of Georgia, Plant Biology, 2502 Miller Plant Sciences, Athens, GA, 30602, USA

Keywords:
gynodioecy
sexual systems.

Presentation Type: Oral Paper
Session: 42, Reproductive Biology
Location: 205/Savannah International Trade and Convention Center
Date: Wednesday, August 3rd, 2016
Time: 10:30 AM
Number: 42002
Abstract ID:386
Candidate for Awards:None