EFFECT OF LEAD AND CADMIUM UPON THE CALCIUM, MAGNESIUM, POTASSIUM, AND PHOSPHORUS CONCENTRATION IN YOUNG CORN PLANTS

Abstract

In a greenhouse experiment corn plants were harvested 24 and 31 days following emergence from pots containing Bloomfield loamy sand (Psammentic Hapladalf). The soil CEC [cation exchange capacity] was 2.3 meq/100 g. The soil had 140 kg/ha of P determined with the Bray P1 extractant, and 220 kg/ha of 1 N neutral ammonium acetate extractable K. Calcium, Mg, K and P concentrations in plant tissue were determined by emission spectroscopy. Treatment combinations were a factorial arrangement of 0, 2.5 and 5 .mu.g/g of Cd and 0, 125 and 250 .mu.g/g of Pb. At 24 days following emergence, there were significant main effects of Cd and Pb upon the Ca, Mg, K and P concentration in corn plants. The Cd linear .times. Pb linear interaction significantly (.alpha. = .05) affected P concentration and uptake of each element. At 31 days following emergence, Cd and Pb main effects influenced the Ca, Mg and K status of the plant, but had no significant effect upon P content. At this stage of development, there were 3 significant Cd-Pb interactions that affected nutrient concentration and 4 interactions that affected nutrient uptake. Results observed in this study suggest that the statistical significance of various effects depends upon stage of development of the corn plant, and that certain Cd-Pb interactions influenced nutrient concentration in the plant.