Figure 4

Root elongation and DWF4-GUS expression under light and in darkness according to the bottom half covered growth (BCG) test. The results of the BCG test revealed that light perception in shoots promotes DWF4 expression in the root apex. (a) Root elongation. Red arrowheads indicate the junctions between the hypocotyl and root, while yellow arrowheads indicate the root apex positions. Hypocotyl (b) and root (c) lengths according to the BCG test. The grey background indicates which part was darkened (n = 32). Means denoted by the same letter are not significantly different (P < 0.05) according to the Tukey–Kramer method. DWF4-GUS expression around the shoot apical meristem (d–h) and in the root apex (i–m). Light conditions with no film (d,i) or with a clear film (e,j). Shoots under light and roots in darkness covered with a black film (f,k). Although the root apex was shaded, the GUS signals in the root meristem were stronger than those of plants maintained in darkness. Dark conditions with no film (g,l) or with a clear film (h,m). Bars represent 10 mm (a) and 50 µm (d–m). Error bars represent standard deviations.