Effects of shortage of calcium and other cations on 45Ca mobility, growth and nutritional disorders of tomato plants (Lycopersicon esculentum)

Abstract

Calcium mobility in tomato plants grown in sand- and water-cultures with little calcium and other cations was studied using 45Ca as a tracer. Radioautographs and 45Ca activity measurements of plant parts showed that 45Ca was “fixed” near the base (root or stem) of plants grown in low-Ca nutrient solutions, compared with plants grown with adequate Ca in which 45Ca was readily translocated to the tops. When plants were grown with little Ca and other cations (i.e. low K, Mg and micronutrients), 45Ca was also readily translocated to the tops. Calcium stress during the fruiting stage caused serious blossom-end rot of fruits, indicating that Ca absorbed by plants before fruiting was not readily available subsequently for fruit development. Leaf total-Ca is not a reliable index for predicting fruit-Ca deficiency in tomatoes.