Floral traits and carbon dynamics of cucumber in response to climate change

Sarah Josina McDonald, The University of Western Ontario

Abstract

Pollination by animals is an important ecosystem service that contributes to the reproduction of many angiosperms. Climate change may alter this mutualism by affecting floral traits that are important to pollinators. Using Cucumis sativus, I tested the effects of experimentally elevated temperature and CO₂ concentration on flowering onset, flower number, flower size, and floral rewards. Additionally, to better understand plant carbon balance and investment in reproduction, I measured biomass partitioning and leaf carbon fluxes of plants under their growth conditions. Carbon dynamics were similar across treatments, and plants grown under high [CO₂] and temperature showed similar biomass production/allocation to control plants. Despite these similarities, both factors altered floral traits in ways that could affect plant-pollinator relationships. However, temperature effects were common, while CO₂ effects were not, suggesting that studies focusing on elevated [CO₂] may be less valuable than studies focusing on elevated temperature or the interaction between [CO₂] and temperature.