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Sex-specific physiological and growth responses to elevated atmospheric CO2 in Silene latifolia Poiret .
Wang, Xianzhong*,1, Griffin, Kevin2, 1 Indiana University-Purdue University Indianapolis, Indianapolis, IN2 Lamont-Doherty Earth Observatory, Palisades, NY
ABSTRACT- Dioecy is found in nearly half of angiosperm families, but little is known about how rising atmospheric CO2 concentration will affect male and female individuals of dioecious species. We examined gender-specific physiological, vegetative and reproductive responses of Silene latifolia Poiret, a widespread dioecious species, to a doubled atmospheric CO2 concentration in environmentally controlled growth chambers. Elevated CO2 significantly increased photosynthesis in both male and female plants and by a similar magnitude. Although there was no gender-specific difference in net photosynthesis, females had significantly greater biomass production than males, regardless of CO2 concentrations. Vegetative mass increased by 35% in males and 33% in females, whereas reproductive mass increased by 78% in males and 92% in females at elevated CO2. As a result, proportionately more carbon was allocated to reproduction in male and female plants at elevated CO2. Higher CO2 increased individual seed mass, but had no significant effect on the number or mass of seeds per female plant. Our results demonstrated that rising atmospheric CO2 will alter the allocation patterns in both male and female S. latifolia Poiret plants. Larger seeds at elevated CO2 suggest that fitness for this weedy species will likely increase in a globally higher CO2 environment.
KEY WORDS: Dioecy , elevated CO2, photosynthesis, reproduction