Factors affecting cadmium uptake by the corn plant

Corn plants, were water-cultured by varying pH and concentration of calcium, phosphorus, zinc, and iron in nutrient solution containing graded levels of cadmium. The results obtained were summarized as follows: 1) With an increase of the cadmium concentration, the cadmium content of plants increased and the total dry weight and grain yield decreased markedly in the absence of calcium. Under these conditions the addition of calcium or iron caused a decrease of the cadmium content, and an increase of the dry weight and grain yield. The pH and the addition of phosphorus or zinc had no notable effect on the cadmium uptake. 2) The relationship between dry weight and cadmium content indicated that the critical cadmium content, above which plants suffer from the cadmium toxicity, was about 20 ppm on a dry matter basis, independent of treatments. 3) Calcium or iron at an adequate concentration in nutrient solution are effective to depress cadmium uptake by corn plants.