Effect of temporary Ca deficiency on fruit growth and element concentrations in the petiole sap of tomato

Tomato plants (Lycopersicon esculentum Mill. cv Momotaro) were cultured in hydroponics. Calcium was withdrawn from the nutrient solution for 3 or 10 days at the flowering stage of the first truss, and the subsequent effect on the growth of fruit and nutrient concentrations in the petiole sap from the leaf just below each truss were investigated. Symptoms of Ca deficiency in the upper leaves appeared in the plant starved of Ca for 10 days when the Ca withdrawl treatment was terminated, but not in that starved for 3 days during the culture. Reduction of marketable yield and occurrence of blossom-end rot of fruits were found in the plant treated with Ca withdrawal from the solution for 10 days. Concentration of Ca in the petiole sap from the leaf just below the first truss decreased during the period of 3 days Ca withdrawal, but increased immediately and almost reached the level of the control after exposure to the complete nutrient solution. However, concentration of Ca in the petiole sap decreased continuously during the period of 10 days Ca withdrawal, and did not recover to the level of the control after exposure to the complete nutrient solution. Concentration of other elements were not influenced by temporary Ca deficiency.