Analysis of phosphate acquisition efficiency in different arabidopsis accessions

The morphological and physiological characteristics of Arabidopsis accessio ns differing in their phosphate acquisition efficiencies (PAEs) when grown on a sparingly soluble phosphate source (hydroxylapatite) were analyzed. A set of 36 accessions was subjected to an initial PAE evaluation following c ultivation on synthetic, agarose-solidified media containing potassium phos phate (soluble) or hydroxylapatite (sparingly soluble). From the five most divergent accessions identified in this way, C24, Co, and Cal exhibited hig h PAEs, whereas Col-0 and Te exhibited low PAEs. These five accessions were analyzed in detail. Significant differences were found in root morphology, phosphate uptake kinetics, organic acid release, rhizosphere acidification , and the ability of roots to penetrate substrates. Long root hairs at high densities, high uptake per unit root length, and high substrate penetratio n ability in the efficient accessions C24 and Co mediate their high PAEs. T he third accession with high PAE, Gal, exhibits a high shoot-to-root ratio, long roots with long root hairs, and rhizosphere acidification. These resu lts are consistent with previous observations and highlight the suitability of using Arabidopsis accessions to identify and isolate genes determining the PAL in plants.