2017 ASHS Annual Conference

Phosphorus (P) deficiency in soil is a global problem. To comprehensively investigate the contribution of root hairs induced with low-P stress to plant growth and P uptake efficiency, a split-root experiment in a hydroponic medium was conducted with a root-hairless mutant barley genotype (brb) and its corresponding wild type (WT-Pallas). A Pi source with limited solubility (tri-calcium phosphate; TCP) was applied to one-half of the root system to create a soil solution with a buffered low-P condition and a nutrient solution without Pi (CNS-P) to the other half. The control was consisted of plants with non-split roots in CNS-P. Root hair variables (length and density), P uptake efficiency, plant biomass and tissue P content were calorimetrically determined for both genotypes. The WT-Pallas in a medium with TCP developed significantly longer and denser root hairs than in a solution with CNS-P. The mutant was defective in root hair formation. Short-term P uptake efficiency, root dry weight and shoot P content in half of the root system of the WT-Pallas with TCP were significantly greater than in the brb, but not different from the CNS-P control. Additionally, there were no significant genotypic or treatments differences in shoot biomass and root P content. The differences in P uptake efficiency and shoot P content between WT-Pallas and brb genotypes were attributed to the root hair development.