Calcium Requirements of Higher Plants

Abstract

THE Hoagland nutrient solution for growing plants calls for the use of 0.004 or 0.005 M calcium and 0.002 M magnesium¹. Plants grown in such solutions contain about the same amount of calcium as plants grown in soil. In the present investigation corn and tobacco plants have been grown with calcium levels 1/50 or less than that of Hoagland solutions. To accomplish this it was necessary to ensure that the copper level of the solutions was 200 p.p.b. or less, that unchelated iron was less than 0.5 p.p.m., that manganese was 0.5 p.p.m. or less, that zinc was 0.1 p.p.m. or less, and that magnesium was 5 × 10⁻⁴ M or less. There were some variations due to plant species.