Figure 3.

Fluence-Response Curves of Continuous Light-Induced Phototropism and Pulse-Induced First Positive Phototropism in the rpt2-2 Mutant.

Dark-grown seedlings were pretreated with or without overhead red light (RL). After 2 h, the hypocotyls were stimulated with unilateral blue light (BL). The hypocotyl curvatures were determined 3 h after the onset of blue light.

(A) Experimental scheme for continuous light-induced phototropism.

(B) Fluence rate-response curves of continuous light-induced phototropism. Dark-grown seedlings were irradiated with unilateral blue light for 3 h. The data shown are means ± se from 38 to 54 seedlings.

(C) Experimental scheme for pulse-induced first positive phototropism.

(D) and (E) Fluence-response curves of pulse-induced phototropism in the rpt2-2 mutant (D) and rpt2-2 transgenic plants harboring 35S_pro:RPT2 (35S) (E). Hypocotyls were stimulated with unilateral blue light at various fluences with (red symbols) or without (black symbols) red light pretreatment. The data shown are means ± se from 16 seedlings. The fitted curves obtained from Columbia (Col) data (Haga and Sakai, 2012) are reproduced as dotted lines, for comparison.