This one year award will support participation of a graduate student in a U.S.-U.K. cooperative research project between Mary A. Bisson of the State University of New York, Buffalo, and A. D. Tomas at the University of Wales. They will study salt tolerance and stress in plants using charophytes, a complex macrophytic algae closely related to the line which gave rise to higher plants. The objective of their research is to test toxicity due to the accumulation of sodium in the plant's cytoplasm. The U.S. investigator brings to this collaboration expertise in plant systems and homeostasis. This is complemented by the Welsh investigator's expertise in ultramicroanalysis, an important new technique for measuring sodium tolerance and stress. These studies will advance our knowledge about salinity in plants and how it determines natural plant distribution and limitations on plant productivity.