Figure 1.

Root phototropic response to unilateral blue light requires PKS1. A, Reduced root phototropism in the pks1, pks1 pks2, and pks1 pks4 mutants and normal responses in the pks2 and pks4 mutants and PKS1, PKS2, and PKS4 overexpressors. B, Roots of representative seedlings. C, Response to fluence rate. Seedlings were grown in full darkness for 2 d and exposed to unilateral blue light for 24 h (1 μmol m⁻² s⁻¹ [A and B] or the indicated fluence rate in C) before measurements. Dark controls were measured simultaneously. Data are means and se of 20 replicate boxes.