Fig. 5

BR restrained the promoted development of the ttl-1 mutant, but not the b1l mutant, under normal conditions. a Primary root length of 7-day-old wild type, ttl-1, and ttl-2 seedlings after treatment with brassinolide, a familiar compound used to analyse the function of BRs in plant growth. b Primary root length of 7-day-old wild type, b1l, and B1L-OE seedlings after treatment with brassinolide. Seedlings in (a) and (b) were germinated and grown on MS plates containing increased concentrations of brassinolide at 22 °C in a 16 h:8 h light:dark cycle. c Hypocotyl growth of 7-day-old wild type and b1l seedlings with brassinolide treatment in the dark. The different concentrations of brassinolide (0.1, 1, 10, 100 nM groups) in panels a, b and c were all dissolved in 80% ethanol. After filter sterilization, they were added to MS plates [1:10000 (v/v)]. The MS plates with 80% ethanol [1:10000 (v/v)] were used as controls (0 nM group). d Hypocotyl growth of 7-day-old wild type and b1l seedlings with brassinazole treatment in the dark. Brassinazole is an inhibitor of BR biosynthesis. The different concentrations of brassinazole (0.025, 0.05, 0.1, 0.2 μM groups) were all dissolved in DMSO and then added to MS plates [1:1000 (v/v)]. MS plates with DMSO [1:1000 (v/v)] were used as a control (0 μM group). Seedlings in (c) and (d) were germinated and grown on MS plates containing increased concentrations of brassinolide or brassinazole at 22 °C grown in the dark condition. Each data point in panels (a, b, c, and d) represents the mean value ± SEM (n = 24). Asterisks indicate significant differences (*p < 0.05) compared with the wild type at each brassinolide or brassinazole concentration