This award will enable Dr. John M. Cheeseman and an assistant from the University of Illinois to collaborate with Dr. Barry F. Clough of the Australian Institute of Marine Science in Townsville, Queensland, Australia. During an 18-day field expedition, they will collect data on the photosynthetic characteristics of three species of mangroves that differ in their strategies of salinity tolerance. For each species, light saturation, quantum efficiency, leaf water potential and salt status will be determined for sun leaves at the top of the canopy and for shade leaves within the canopy on trees located along a natural salinity gradient. The purpose of this research is to gain insight into the photosynthetic characteristics and environmental responses which allow mangroves to be the dominant plants in a highly stressful but highly productive ecosystem. The project will benefit from the complementary backgrounds of and instrumentation available to the investigators. Dr. Cheeseman's work has involved laboratory-based studies on the physiology of salt tolerance in plants. Dr. Clough is an expert on mangrove physiology with extensive field experience. The Australian Institute of Marine Science maintains a permanent field site on the Daintree River which is appropriately positioned for sampling across a natural salinity gradient.
