Figure 4.

ICMT Overexpression Lines of Arabidopsis Exhibit Reduced ABA Induction of Stomatal Closure Compared with Control Col-0 Plants.

(A) Stomatal apertures were measured for Col-0, ICMT^ox1, and ICMT^ox2 lines after incubation of excised leaves for 2 h in the presence of 0, 0.5, or 2.5 μM cis-ABA. Stomatal apertures were measured from photomicrographs of epidermal peels and reported as averages of 50 stomata per data point.

(B) Root growth was measured after transferring seedlings (21 < n < 51) to plates containing various concentrations of ABA. The seedlings were placed 90° from vertical, and growth from the bend to the tip was recorded after 5 d.

The se is shown for all data points. Asterisks represent significant differences from the control of * P < 0.05 and ** P < 0.001, as determined by Student's t test.