Salt induces agravitropic response in Arabidopsis. Five-day-old wild-type Col-0 seedlings germinated on MS medium were transferred onto medium containing different concentrations of NaCl (0, 50, 100, 150 mm) in petri dishes and then were placed vertically (A). B, A two-layer medium. MS medium was on the top and salt on the bottom, and the arrows indicate the interface between the two media. The pictures were taken 6 d after transferring (A) or germination (B).