EAPSI: Does Branch Photosynthesis Mitigate Water Loss in Tropical Trees During Drought?

Stutz Samantha S, Los Alamos NM

Investigators

Abstract

This award supports research on how branch photosynthesis varies in four tropical tree species under drought and non-drought conditions. Tropical rainforests are some of the most productive and diverse biomes on Earth. However, climate change is expected to increase the frequency and severity of droughts in tropical rainforests. For plants to survive a drought they must continue to photosynthesize while minimizing water loss. This study aims to understand how tropical trees utilize branch photosynthesis to minimize water loss and survive droughts. While previous research has measured branch photosynthesis, little effort has gone into understanding or modeling branch photosynthesis under drought. The research will be conducted at the Daintree Rainforest Observatory in Queensland, Australia, under the direction of Professor Lucas Cernusak, a world expert in branch photosynthesis. Most CO2 for photosynthesis is obtained through stomata, small pores in the leaves; however, this CO2 gain comes at the expense of water loss. Drought severity and frequency in tropical rainforests is expected to increase with climate change, which in turn will lead to a decrease in photosynthesis and an increase in plant mortality. Plants can minimize water loss while still photosynthesizing through branch photosynthesis, which recycles respired CO2. The researcher will conduct field work at the Daintree Rainforest Observatory operated by James Cook University Cairns Campus. Collaboration with Professor Cernusak, a world expert in branch photosynthesis, will be an essential component of the project. This research will increase the knowledge of how tropical trees respond and adapt to drought stress. Additionally, this research will provide mathematical models of branch photosynthesis that can be applied to other tree species. This award under the East Asia and Pacific Summer Institutes program supports summer research by a U.S. graduate student and is jointly funded by NSF and the Australian Academy of Science.