Mechanism of the Differential Response of Wf9 and Oh40B Corn Seedlings to Iron Nutrition1

Abstract

AbstractThe mechanism of differential response of corn (Zea muys L.) inbred lines, Oh40B and Wf9, to Fe nutrition was studied in sand and water cultures in a greenhouse. Oh40B was inefficient while Wf9 was nutritionally efficient with respect to utilization of Fe. Wf9 had a higher concentration of Fe in the tissues than Oh40B at several roncentrations of Fe in the nutrient medium, but the difference was not sufficient to account for the observed differences in chlorosis.In experiment testing the effects of Fe with other ions, Oh40B seedlings accumulated more P and Mn and showed more chlorosis than Wf9. Fe toxicity symptoms were induced in Wf9 and not in Oh40B cultured at high levels of Fe. It is concluded that Oh40B is more susceptible to chlorosis in the seedling stage than Wf9 because of its low Fe:P and Fe:Mn ratios and consequently lower amounts of available Fe. Conversely Wf9 is more prone to Fe toxicity because of its greater concentration of available Fe in the tissues, as indicated by the higher Fe:P and Fe:Mn ratios. Oh40B recovered from chlorosis at tasseling with a concomitant decrease in P and Mn concentrations.