Sme. Satti et Ra. Alyahyai, SALINITY TOLERANCE IN TOMATO - IMPLICATIONS OF POTASSIUM, CALCIUM, AND PHOSPHORUS, Communications in soil science and plant analysis, 26(17-18), 1995, pp. 2749-2760
The effect of salinity on the growth and yield of tomato plants and mi
neral composition of tomato leaves was studied. Five tomato (Lycopersi
con esculentum Mill) cultivars, Pearson, Strain B, Montecario, Tropic,
and Marikit, were grown in sand nutrient culture. The nutrient soluti
ons applied consisted of a modified half-strength Hoagland solution wi
th 50 mM sodium chloride (NaCl), 3 mM potassium sulphate (K2SO4), 1.5
mM orthophosphoric acid (H3PO4), and 10 mM calcium sulphate (CaSO4). S
tem height and number of leaves of tomato plants were not found to be
significantly different but leaf and stem dry weight were reduced sign
ificantly in plants irrigated with saline nutrient solution in contras
t with control plants. The total yield was reduced in plants that rece
ived saline treatments, but there was no significant difference in fru
it number and fruit set percentage. The fruit electrical conductivity
and total soluble solids were increased in plants irrigated with salin
e nutrient solution. Fruit pH was not found to be significantly differ
ent among salinity treatments. Mineral composition of tomato leaves we
re increased by addition of potassium (K), phosphorus (P), and calcium
(Ca) to the saline nutrient solution. The addition of K to the soluti
on resulted in an increase in sodium (Na) leaf content. The amounts of
K and magnesium (Mg) were not significantly different among salinity
treatments. Calcium content was increased when CaSO4 was added. Applic
ation of H3PO4 resulted in the highest amount of P in tomato leaves un
der saline conditions. The present study revealed that application of
K, P, and Ca under saline conditions improved fruit electrical conduct
ivity and total soluble solids. Sufficiency levels of the mineral nutr
ients K and P were obtained in tomato leaves when the appropriate nutr
ient was used in the saline solution.