Figure 4.

Developmental gradient of ARs in the dark. A, cv PG56 stem sections were excised 2 cm below the first, second, third, or fourth node and kept in white light or darkness for 2 d. Subsequently, root penetration was determined. B, Mean ± se root angles at each node were determined from 16 stems analyzed in three independent experiments. Different letters indicate statistically significant differences between nodes in the dark (n = 16; P < 0.05, ANOVA with Tukey’s test). Asterisks indicate significant differences between dark and light treatments at each node (P < 0.05, Student’s t test; nd, no data).