Pollen performance of Raphanus sativus (Brassicaceae) declines in response to elevated [CO2]

Although increases in atmospheric CO₂] are known to affect plant physiology, growth and reproduction, understanding of these effects is limited because most studies of reproductive consequences focus solely on female function. Therefore, we examined the effects of CO₂ enrichment on male function in the annual Raphanus sativus. Pollen donors grown under elevated CO₂] initially sired a higher proportion of seeds per fruit than ambient CO₂]-grown plants when each was tested against two different standard competitors; however, by the end of the 5-month experiment, these pollen donors sired fewer seeds than ambient CO₂]-grown plants and produced a lower proportion of viable pollen grains. The results of this experiment confirm that elevated CO₂] can alter reproductive success. Additionally, the change in response to elevated CO₂] over time varied among pollen donor families; thus, changes in CO₂] could act as a selective force on this species.