Abstract

Phosphorus depletion curves were used to compare the P uptake characteristics of roots of chickpea, pigeonpea, soybean, and maize in solution culture. Half-maximal P uptake rates (Km) were attained at lower concentrations of P in the solution in chickpea and pigeon-pea. These species also absorbed P less rapidly than maize or soybean at higher concentration of P in the solution. However, the differences in the kinetic parameters could not adequately account for the lack of response of chickpea to P fertilizer on soils with <1 μM P in the soil solution. Further mechanisms by which P uptake efficiency in chickpea is enhanced, such as development of root hairs, role of mycorrhizae and the ability to solubilize soil P, would have to be considered.