Figure 1.

OPAQUE1 is required for normal subsidiary cell formation in maize. A) Division sequence of stomatal development in maize and other grasses. B) Percentage of abnormal subsidiary cells and C) percentage of aborted GMCs in o1 mutants (o) and their wild-type siblings (wt). In (B and C) seeds were scored based on the appearance of their endosperm (o, seeds that are phenotypically opaque; wt, translucent seeds). Each data point represents the percentage of abnormal cells from 1 plant; between 100 and 200 cells were counted per plant. Gray horizontal bars indicate means. ANOVA comparing each mutant to wild-type sibling returned P < 0.0001 for all 3 alleles. D) Methacrylate impression of the leaf epidermis of a wild-type sibling showing normal stomatal complexes. E)o1-ref mutant showing abnormal subsidiary cells (red arrowheads) and aborted GMC (blue arrowhead). Abnormal cells in (E) are highlighted in yellow.