Fig. 4: H₂O₂ promotes stomatal development.

a, b Quantification of epidermal cell types of Col-0 and indicated plants, expressed as percentage of total cells. GMC, guard mother cell; M, meristemoid. n = 13, 14, 14, 14, 14, 14, 15, 15, 12 independent cotyledons were examined in b. Seedlings of wild-type Col-0 and indicated plants were grown on ½ MS solid medium containing 1% sucrose under 16 h light/8 h dark photoperiod with 100 µMol/m²/s for 5 days. c, Quantification of the effects of H₂O₂ on stomatal index. n = 12, 15, 14, 12 (Col-0), n = 12 (kin10) independent plants were examined in c. Seedlings of wild-type Col-0 and kin10 mutant were grown on ½ MS solid medium containing 1% sucrose and different concentrations of H₂O₂ under 16 h light/8 h dark photoperiod with 100 µMol/m²/s for 8 days. d–g CAT mutations altered cell fate in Arabidopsis epidermis. n = 14, 15, 16, 15 independent cotyledons were examined in e. n = 13, 16, 13, 16 independent cotyledons were examined in g. Seedlings of pSPCH::nucGFP, pSPCH::nucGFP/cat2 cat3, pSPCH::SPCH-GFP, and pSPCH::SPCH-GFP/cat2 cat3 were grown on ½ MS solid medium containing 1% sucrose with or without 1 mM KI under 16 h light/8 h dark photoperiod with 100 μMol/m²/s for 3 days. Error bars indicate standard deviation (S.D.). Different letters above the bars indicated statistically significant differences between the samples (One-way ANOVA analysis (b), Two-way ANOVA analysis (c) followed by Uncorrected Fisher’s LSD multiple comparisons test, p < 0.05; No adjustments were made for multiple comparisons test; Brown-Forsythe ANOVA analysis followed by Dunnett’s T3 multiple comparisons test, p < 0.05 (e, g). Adjustments were made for multiple comparisons test). Scale bars in confocal images represent 20 µm.