PARENT SESSION
Oral Session #10: Elevated CO₂.
Presiding: D. Hileman
Monday, August 5. 8:00 AM to 11:30 AM. Grand Ballroom East, Radisson.

Elevated CO₂ increases siring success and pollen production in Raphanus sativus, wild radish.

Tyler, Anna^*,1, Marshall, Diane¹, ¹ University of New Mexico, Albuquerque, New Mexico

ABSTRACT- Elevated CO₂ may act as a selective agent if genotypes vary in their response to elevated CO₂ and this variation affects their reproductive success. Wild radish, Raphanus sativus, was used as a model organism to study the effects of elevated CO₂ on male reproductive characters. Elevated CO₂ increases rates of photosynthesis and growth, and can stimulate flower and seed production. The effects of elevated CO₂ on developing pollen grains and siring success, the male half of plant reproduction, have been largely ignored. Individuals from full sibling pairs of pollen donors were grown in one of two CO₂ levels: ambient (360ppm) or elevated (725ppm). Pollen collected from these plants was used to pollinate a set of unrelated plants growing under greenhouse conditions with ambient levels of CO₂ . Additionally, flowers with intact, undehisced stamens were collected from the donors in order to measure pollen size and quantity. Exposure to elevated CO₂ during pollen development significantly increased siring success and viable pollen production, without significantly affecting pollen volume. All genotypes showed plasticity in their response to elevated CO₂ , and the direction of the response varied among families. We believe that elevated CO₂ has the potential to act as a selective agent on male fitness characters.

KEY WORDS: Elevated CO₂, pollen, siring success, Raphanus sativus