Figure 3.

Pi deprivation-triggered secreted APase activity, anthocyanin accumulation, and reduction of seedling fresh weight are impaired by BZR1. A, In vivo root APase staining. Blue precipitates on the root surface represent APase cleavage of exogenously applied 5-bromo-4-chloro-3-indolyl phosphate substrate. Note the low staining in bzr1-D roots compared with the wild type under Pi-deprived conditions (1 μm). Bar = 5 mm. B, Anthocyanin content. C and D, Fresh weight of the wild type and bzr1-D grown as under Pi-deprived conditions. C, Fresh weigh of shoots and roots. D, Fresh weigh of shoots of the same seedlings used in C. Note that, under depleted Pi conditions, roots contribute to the increase in fresh weight of bzr1-D in contrast to the wild type. Error bars represent se. *, P < 0.05 with two-tailed Student's t test. **, P < 0.01 with two-tailed Student's t test.