SALT TOLERANCE IN THE WILD RELATIVES OF THE CULTIVATED TOMATO: PROLINE ACCUMULATION IN LYCOPERSICON ESCULENTUM MILL., L. PERUVIANUM MILL. AND SOLANUM PENNELLI COR. TREATED WITH NaCI AND POLYETHYLENE GLYCOLE

The cultivated tomato Lycopersicon esculentum cv. Rhemlands Ruhm and the two wild species L. peruvianum and Solomon pelnnellii which originated in dry habitats were compared with respect to accumulation of free proline, chloride and succulence under NaCl stress, and accumulation of proline and succulence under water stress produced by polyethylene glycole. Proline accumulation increased in all three species under both types of stress. Increase under salinity stress, however, was smaller in the two wild species which accumulated more chloride and were more succulent. Under water stress, the increase of proline level was greatest in is. pennellii, in which succulence decreased drastically, and smallest in L. peruvianum. The possible role of salt tolerance in enabling wild tomato species to endure drought, and the difference between them with respect to proline accumulation, are discussed.