Phosphorus efficiencies and their effects on Zn, Cu, and Mn nutrition of different barley (Hordeum vulgare) cultivars grown in sand culture

Abstract

A sand-culture experiment was carried out in a growth chamber to investigate the phosphorus (P) efficiencies of 8 barley cultivars that are parents of 4 mapping populations, and the effects of P nutrition on plant uptake of zinc (Zn), copper (Cu), and manganese (Mn). Two sources of phosphate were used, rock phosphate (sparingly soluble) and CaHPO₄ (readily available). There were significant differences in P uptake and utilisation efficiencies between the 8 cultivars. Among the cultivars, the Sahara–Clipper pair is of the most interest, because these 2 cultivars had large differences in root/shoot ratios, P allocation between root and shoot, and P uptake/utilisation efficiencies. Higher P availability significantly reduced plant Zn uptake and tissue concentrations in all cultivars. Shoot Zn concentrations were found to decrease significantly with P influx to the xylem (P < 0.01), indicating that genotypic variations in P translocation from roots to shoots may interact with Zn accumulation in shoots. Higher P availability reduced Cu concentrations in shoots, probably due to a dilution effect. P availability (rock phosphate v. CaHPO₄) seemed to affect plant uptake of Mn in some cultivars, but further study is needed to elucidate the mechanisms involved and the practical implications of this interaction in Mn-deficient soils.