ACCUMULATION OF PROLINE AND QUATERNARY AMMONIUM-COMPOUNDS IN MATURE LEAVES OF WATER-STRESSED COFFEE PLANTS (COFFEA-ARABICA AND C-CANEPHORA)

Water stressed coffee plants of five genotypes of C. arabica and one o f C. canephora were compared with watered controls for their accumulat ion of proline and quaternary ammonium compounds. These solutes, mainl y proline, accumulated in mature leaves under water stress, their conc entration being related to the osmotic potential at zero turgor and to the osmotic adjustment either in well watered or droughted plants. Pr oline accumulated to a greater extent than quaternary ammonium compoun ds under water stress.