Fig. 2.

Quantification of protophloem differentiation defects in brassinosteroid receptor mutants. (A) Protophloem differentiation in Col-0 wild type or bri1 brl1 brl3 brassinosteroid receptor (‘triple’) mutants (confocal microscopy, inverted gray scale). Asterisks indicate protophloem sieve element strands, arrowhead points out gap cells in the triple mutant. (B,C) Quantification of root growth (B) and gap frequency (C) in seedlings transferred onto indicated media for 3 days at 4 days old. (D-F) Macroscopic phenotype (D), root growth quantification (E) and gap frequency (F) of 5-day-old seedlings. C and F show the proportion of phloem poles with or without gaps; B and E show mean±s.e.m. *P<0.05; **P<0.01; ***P<0.001; ^aversus Col-0; ^bversus bri1 brl1 brl3 [Student's t-test (B,E) or Fisher's exact test (C,F)].