PROLINE ACCUMULATION IN LEAVES OF NACL-SENSITIVE AND NACL-TOLERANT TOMATOES

Proline (Pro) accumulation in leaf discs of the NaCl-treated salt sens itive Lycopersicon esculentum was higher than in the salt tolerant L. pennellii. The magnitude of Pro accumulation differed when leaf discs of both species were floated in the light or under darkness, and in va rious incubation media: buffer solutions (pH from 3.9 to 7.8), abscisi c acid, isobutyric acid, NH4Cl, malate, citrate, and mixtures of NaCl and KCl, NaCl and CaCl2, and NaCl and mannitol. Under darkness, Pro ac cumulation in L, esculentum was not regulated by salts. Conversely, th e light-independent NaCl-induced Pro accumulation observed in L. penne llii became light-dependent when CaCl2 was added. The different expres sion patterns of Pro accumulation reinforce the proposal of two Pro me tabolic pathways in the domestic and the wild tomatoes.