BARLEY GENOTYPES DIFFER IN ACTIVITY OF SOLUBLE EXTRACELLULAR PHOSPHATASE AND DEPLETION OF ORGANIC PHOSPHORUS IN THE RHIZOSPHERE SOIL

In the present investigation we studied the extent of variation among barley genotypes (Hordeum vulgare L. cv. Alexis, Canut, Digger, Etna, Peel) in their ability: i) to induce activity of soluble extracellular phosphatase in rhizosphere soil. ii) to withdraw bicarbonate extractable organic phosphorus (NaHCO3-P-o). All the genotypes induced 3-4 times higher phosphatase activities in rhizosphere soil as compared to bulk soil. Among the genotypes, there were significant (p > 0.01) differences in soluble extracellular and non-soluble phosphatase activities and depletion of NaHCO3-P-o in soil near their root mats. Etna induced highest phosphatase activities and depleted most NaHCO3-P-o from the rhizosphere soil. A high correlation (r = 0.79) was found between the activity of soluble extracellular phosphatase and the quantity of NaHCO3-P-o withdrawn from the rhizosphere soil by the barley genotypes.