Auxin and cadmium(Cd) stress play critical roles during root development.There are only a few reports on the mechanisms how Cd stress influences auxin homeostasis and affects primary root(PR) and lateral root(LR) development,whereas there is almost nothing known how auxin and Cd interfere with root hair(RH) development.Here,we characterize rice osaux1 mutants that have longer PR and shorter RH in hydroponic culture,and that are more sensitive to Cd stress compared to WT/Dongjin(DJ).OsAUX1 expression in root hair cells is different from its paralogous gene,AtAUX1,expressed in non-hair cells.