GROWTH, YIELD AND WATER RELATIONS OF NORMAL FRUITED AND CHERRY TOMATO CULTIVARS IRRIGATED WITH SALINE WATER

Plants of a tomato cultivar of normal fruit-size, weak vegetative development and high productivity (L. esculentum cv. New Yorker) and another of small fruit-size (cherry) and strong vegetative development (L. esculentum var. cerasiforme cv. PE-62) were grown in an unheated plastic greenhouse and irrigated with 0 and 140 mM NaCl water (control and saline treatments, respectively). The shoot and leaf dry weights and leaf area reductions induced by salinity were related to the osmotic adjustment achieved at each time and cultivar. Plants of cv. PE-62 showed a decrease in shoot to root dry-weight ratio in response to salinity. Yields of both cultivars were reduced significantly by salinity; a result of a fewer fruits and smaller fruits. Fruits from salt treated plants contained a higher concentration of reducing sugars and organic acids than those of control plants. The fruit life span was shortened in plants under saline stress. In both cultivars, the leaf osmotic potential at full turgor (PSI(os)) levels were reduced by salinity. The parallel pattern observed in both cultivars, between PSI(os) and PSI(tlp) (leaf water potential at turgor loss point) could indicate that PSI(os) values were controlling the behaviour of PSI(tlp). The bulk modulus of elasticity (E) and the relative water content at the turgor loss point (RWC(tlp)) were not affected by salinity. The RWC(tlp) values in both cultivar seems to be controlled by E values.