ACCUMULATION OF TOXIC LEVELS OF PHOSPHORUS IN THE LEAVES OF PHOSPHORUS-DEFICIENT BARLEY

Abstract

Leaves of P-deficient barley (Hordeum vulgare L.) plants were damaged after the addition of P to the hydroponic solution. These damaged leaves accumulated abnormally high percentages of P. Damage was severest in the apical regions of the youngest leaves. The facts that P accumulated in the leaf tips of P-deficient plants after P exposure whereas N did not, and that continuous exposure to high-solution P did not result in high tissue percent P, suggested that a source-sink control mechanism, and not just transpirational uptake and accumulation was involved.