RELATION OF NUTRIENT SALT CONCENTRATION TO GROWTH OF THE TOMATO AND TO THE INCIDENCE OF BLOSSOM-END ROT OF THE FRUIT

Abstract

Marglobe tomato plants were grown in sand cultures with complete nutrient solns. of approx. the same proportion of nutrient salts but of 5 different osmotic cones., namely, 0.08, 0.44, 0.83, 1.70 and 3.10 atmospheres. Plants grown with the solns. of the 3 intermediate cones, had greater green and dry wts. per plant than those grown with the soln. of highest or of lowest cone. Fruits from plants grown with solns. of low cone, were exceptionally large, whereas those grown with solns. of high cone, were relatively small. Approx. 80% of fruits grown with solns. of high cone, developed blossom-end rot; this disorder did not affect fruits grown with the soln. of lowest cone. There was a difference of approx. 4 atm. between the osmotic values of the extracted juices of similar tissues of plants grown with solns. of lowest and of highest cones. An osmotic gradient varying from 1.6 to 3.6 atm. was found between the extracted juices of the tissues of the fruits and those of the stems and leaves of the several treatments. The incidence of blossom-end rot was associated with wide fluctuations in the rate of atmospheric evaporation of water.