Figure 4.

Spectral dependence of the number of small and large phyB-NBs in leaf petiole cells. A, Arabidopsis plants were grown under high-irradiance white light for 2 weeks, transferred to high-irradiance white minus blue (orange), high-irradiance red, high-irradiance blue, or low-irradiance white light 2 h after the beginning of the photoperiod and analyzed 4 h later. Controls remained under high-irradiance white light. Data are means ± se of seven plant replicates. Different letters denote significant differences among means (P < 0.05) in Bonferroni posttests. B and C, Plants were grown under high-irradiance white light for 2 weeks and transferred to the indicated irradiance of red light. The angle of the leaves (B) and the number of phyB-NBs (C) were measured 2 h later. Data are means ± se of 18 (A) or six (B) plant replicates. Linear regression analysis indicates significant slope deviation from zero (B, P < 0.0001; C, P < 0.05). [See online article for color version of this figure.]