Sex‐specific physiological and growth responses to elevated atmospheric CO 2 in Silene latifolia Poiret

Dioecy is found in nearly half of the angiosperm families, but little is known about how rising atmospheric CO 2 concentration will affect male and female individuals of dioecious species. We examined gender‐specific physiological and growth responses of Silene latifolia Poiret, a widespread dioecious species, to a doubled atmospheric CO 2 concentration in environmentally controlled growth chambers. Elevated CO 2 significantly increased photosynthesis in both male and female plants and by a similar magnitude. Males and females did not differ in net photosynthetic rate, but females had significantly greater biomass production than males, regardless of CO 2 concentrations. Vegetative mass increased by 39% in males and in females, whereas reproductive mass increased by 82% in males and 97% in females at elevated CO 2 . As a result, proportionately more carbon was allocated to reproduction in male and female plants at elevated CO 2 . Higher CO 2 increased individual seed mass significantly, but had no effect on the number or mass of seeds per female plant. Our results demonstrated that rising atmospheric CO 2 will alter the allocation patterns in both male and female S. latifolia Poiret plants by shifting proportionally more photosynthate to reproduction.