Figure 1.

Isolation of the rib1 mutant. Picture taken during the screen for root gravitropic mutants. Seedlings were grown on vertically oriented plates for 4 d then the plates were rotated on edge 90° and photographed 24 h later. The rib1 root response (top) can be compared with the wild-type root response (bottom). An asterisk indicates the hatch mark showing the position of the root at the time the plate was first rotated. The arrow to the right of the picture indicates the direction of the gravitational vector after rotation. The picture was taken on a stereomicroscope (Leica, Wexlar, Germany) at a magnification of 6.3×.