Figure 1.

ARs of rice emerge and grow upward in the dark. A, cv PG56 rice stem sections were exposed to white light (WL) or darkness (D) for 2 d. ARs emerged in the dark but not in the light. B, Percentage of penetrated roots. C, Average angle of ARs at the third youngest node. Bars in B and C indicate means ± se from four independent experiments, with 30 stem sections analyzed in total per treatment. Different letters indicate significantly different values between treatments (P < 0.05, Student’s t test). D, Time-course analysis of AR elongation and root growth angle in the dark. Values are means ± se of three independent experiments, with 18 stems analyzed per time point. Uppercase letters indicate significantly different values of root angle between different time points, and different lowercase letters indicate significantly different values of root length between different time points (P < 0.05, ANOVA with Tukey’s test).