Fig. 2. HISTONE 4 expression during wild-type and jag-1 petal development. (A) Graph showing average number of H4-expressing cells in medial-longitudinal sections of petal primordia. Wild type (red, square), jag-1 (blue, circle). Error bars indicate 95% confidence intervals (2x standard error of the mean). (B) Medial-longitudinal section through petal primordia from stage 7 to 12. Note high frequency of H4-expressing cells in distal region. (C) H4 expression in petals of jag-1 mutants. Total number of petals examined for each stage range from 8 to 17 for wild type and 8 to 26 for jag-1. Scale bars: 50 µm (B,C stages 7-10) and 80 µm (B,C stages 11, 12).