Figure 1.

Impaired Phototropisms of cpt1 Coleoptiles and Roots.

(A) Phototropic fluence rate-response curves. Seedlings of the cpt1 mutant (open circles) and the wild type Nihonmasari (closed circles), grown for 3 d under red light (2.5 to 3 μmol m⁻² s⁻¹), were stimulated continuously with unilateral blue light at the indicated fluence rates. The length of coleoptiles was in the range between 3.5 and 4.5 mm at the onset of blue light. Phototropic curvatures of coleoptiles (top panel) and primary roots (bottom panel) were determined at 6 h of stimulation. The means obtained from 30 to 50 seedlings are shown. The vertical bar indicates ±se.

(B) Photographs illustrating impaired phototropisms of cpt1 coleoptiles and roots. Wild-type and cpt1 seedlings were stimulated with unilateral blue light at a fluence rate of 0.1 μmol m⁻² s⁻¹ (top panels) or 10 μmol m⁻² s⁻¹ (bottom panels). Each pair of photographs was taken just before and after 6-h blue light stimulation. Other conditions were as described for (A).