Zinc-phosphorus-iron interaction studies in maize

Abstract

The effect of Z n -P -F e interaction in the nutrition of the maize plant was first examined by a well-controlled pot culture experiment and the results subsequently evaluated by a field trial.Dry matter production by root and shoot was affected significantly by the nutrient interaction. Enhanced P application reduced Zn concentration in shoot by more than half as compared to root. While Zr~ concentration per se in the plant increased, its relative mobility from root to shoot was vastly impeded, implying a physiological inhibition in movement from root to shoot. Root uptake of P almost doubled resultant from enhanced P application indicating a 'concentration effect'. A 'locking up' process of P movement from root to shoot was observed. Relatively more Fe than Zn was root absorbed and immobilized resulting in reduced translocation to shoot. Dry matter yield increases were recorded generally at or around a P/Zn ratio of 19 and 65 respectively in root and shoot. Corresponding values for P/Fe and Fe/Zn ratios were 284 and 11 and 67 and 6 respectively. Sampling of the substrate at 15 days interval indicated decreased availability of Zn, P and Fe as a function of time consequent to plant growth. Significant differences in availability with reference to higher amounts of applied Zn were observed only later during crop growth, while in the case of P and Fe they were observed at each sampling. Available Zn and P correlated positively with plant shoot and root tissue concentration. With Fe, the correlation was negative in the case of shoot. The contrasting 'r' values of Zn and Fe in shoot implicates the strong possibility of P-induced Zn-Fe antagonism.Field evaluation of the experiment indicated the depressing effect of high P application on grain yield and also its nullifying effects on the otherwise positive effect of Zn and Fe application.

Zinc bioavailability in maize grains in response of phosphorous–zinc interaction

“…The treatments receiving no P application had the highest Zn concentration in both genotypes, whilst single P application tended to reduce the Zn concentration. These results corroborate earlier findings of Farah and Solimon (1986), Olsen (1972), and Nair and Babu (1975). The decrease in Zn concentration due to P application at 60 kg ha −1 may result from the formation of soluble Zn‐P compounds in the soil as reported by Krishnasamy (1993).…”

Early Responses of Brassica oleracea Roots to Zinc Supply Under Sufficient and Sub-Optimal Phosphorus Supply

“…By contrast, roots of P-starved A. thaliana plants had significantly larger Fe concentrations than did roots of P-replete plants in two different studies (Misson et al, 2005;Baxter et al, 2008;Raghothama et al, 2008), as did roots of bush bean (Phaseolus vulgaris L.; Wallace et al, 1974) and rice seedlings (Zheng et al, 2009). No effect of P supply was observed on Fe concentrations in roots of maize (Prabhakaran Nair and Rabu, 1975) or poplar (Kavka and Polle, 2017). These contradicting observations preclude consensus on the interactions between P deficiency and Fe nutrition, but they do indicate crosstalk between Fe and P nutrition which merits further investigation Figure 5A for schematic representation of comparisons.…”