OSMOTIC ADJUSTMENT IN LEAVES OF LYCOPERSICON-ESCULENTUM AND L-PENNELLII IN RESPONSE TO SALINE WATER IRRIGATION

Two tomato species (Lycopersicon esculentum and L. pennellii) were gro wn under unheated plastic greenhouse and irrigated with 0 or 140 mM Na Cl. Salinity induces a more important reduction in predawn leaf water potential (PSI(pd)) in L. esculentum than in L. pennellii. In both spe cies the osmotic adjustment was achieved by active solute accumulation . The leaf water potential at turgor loss point (PSI(tlp)) seemed to b e controlled by leaf osmotic potential (PSI(os)). The results revealed the existence of limits to the accumulation of osmotic solutes in lea f tissues and the existence of an ontogenetic effect on the solute acc umulation. In both species, but essentially in L. pennellii the inorga nic solutes contribution especially Na+ and Cl- accumulation to PSI(os ) was higher than the organic solutes. Therefore, wild species save en ergy more markedly.