Figure 3.

Effects of the NPH3^SA and NPH3^SE mutations on the fluence rate-response curves for the continuous light-induced second positive phototropism and fluence-response curves for the pulse-induced first positive phototropism. A, Fluence rate-response curves for the continuous light-induced second positive phototropism. Two-day-old etiolated seedlings of the nph3 mutant and those transformed with 35Spro:NPH3^WT (NPH3^WT #2), 35Spro:NPH3^SA (NPH3^SA #26), or 35Spro:NPH3^SE (NPH3^SE #7) constructs were irradiated with unilateral BL at various fluence rates for 3 h. The data shown are the mean values ± SE from 17 to 26 seedlings. B, Fluence-response curves for the pulse-induced first positive phototropism. Two-day-old etiolated seedlings of the nph3 mutants and those transformed with 35Spro:NPH3^WT (NPH3^WT #2), 35Spro:NPH3^SA (NPH3^SA #26), or 35Spro:NPH3^SE (NPH3^SE #7) constructs were stimulated with unilateral BL at various fluence rates for 1 min. The hypocotyl curvatures were determined at 3 h after the onset of BL stimulation. The data shown are the mean values ± SE from 19 to 31 seedlings. Asterisks indicate a statistically significant difference from the curvatures at 1.0 × 10⁻¹ µmol m⁻² for NPH3^WT #2 and NPH3^SE #7 and those at 1.0 × 10^−0.5 µmol m⁻² for NPH3^SA #26 within respective lines (Dunnett’s test, P < 0.05).