RESPONSE OF TOMATOES, A CROP OF INDETERMINATE GROWTH, TO SOIL-SALINITY

Tomatoes were grown in tanks filled with loam and clay, and were irrig ated with waters of three different levels of salinity. Osmotic adjust ment was determined by analysing the pressure-volume curves at four gr owth stages. Owing to the osmotic adjustment, tomatoes are able to mai ntain the turgor potential and the stomatal conductance at the same va lue for the lower Values of the leafwater potential. Salinity affected the pre-dawn leaf-water potential, stomatal conductance, evapotranspi ration, leaf area and fruit yield on both soils. Soil texture only aff ected the fruit yield. The evapotranspiration showed a moderate decrea se, owing to the small decrease in leaf area and the effect of osmotic adjustment on the stomatal conductance, whereas the fruit yield decre ased strongly. The tomato plant apparently favours under saline condit ions, the growth of foliage at the expense of fruit formation. (C) 199 8 Elsevier Science B.V. All rights reserved.