This project uses the fern Ceratopteris as an experimental plant system that provides several advantages for such studies, including: a variety of confirmed mutants derived from the same salt sensitive wild type genotype, the ability to rapidly characterize the genetic basis of the various mutants, the ability to precisely determine quantitative responses to stress, and the ability to efficiently carry out physiological and genetic studies on both a simple haploid gametophyte and a developmentally complex vascular sporophyte phase of the life cycle. Initial studies show that while the effects of single genes on tolerance may be modest, specific combinations exhibit synergistic effects, resulting in high levels of tolerance. The physiological and genetic complexity associated with natural salt tolerance is most likely based upon similar gene interactions. The availability of the described mutants and the advantages of this plant system provide a unique opportunity to study fundamental aspects of salt tolerance in plants. %%% The development of crops with enhanced tolerance to salt and other osmotic stresses is an important objective in dealing with the worldwide problem of excess salinity on agricultural land. However, the complex basis of salt tolerance is incompletely understood. Fundamental genetic and physiological studies are needed.
