Fig. 2.

Petal development in wild type and mutants. (a) Floral organ development stages 2, 4 and 5 (21, 22). At stage 4, two instead of one ventral sepals are initiated in syp1-1 floral meristem (yellow star). At stage 5, one dorsal petal and two stamens are initiated in wild type (blue ellipse), whereas the dorsal primordia fail to differentiate in k-1 lst1-1 (blue ellipse). At the same stage, extra primordia can be found in syp1-1 (yellow ellipse) in comparison with the wild type (yellow ellipse). Blue and yellow arrows indicate the dorsal and ventral region of the floral meristem, respectively. (b) Percentage of flowers with variable organ number. Blue: in the dorsal region. Yellow: in the ventral region. wt: JI992; k: k-1; lst1: lst1-1; k lst1: k-1 lst-1; syp1: syp1-1; k-1 lst1-1 syp1: k-1 lst1-1 syp1-1. Eighty flowers were scored in each genetic background. (c) Epidermal cell on the adaxial side of mature petals. In wild type, a representative cell type of dorsal petals is a long strip with wavy margins, one of the lateral petals is jigsaw puzzle-like, and the one of the ventral petals is ripple-like. The petal cells of the lateral petals in k are identical to that of the ventral petal, and the dorsal petal cells of lst1 resemble that of the lateral petal in wild type. Cells of all petals in k lst1 bear those of the ventral petals in wild type, whereas no differences between wild type and syp1 were observed. (d) Petal development, stage 6. Red arrow: the asymmetric shape of both lateral and ventral petals is obvious in the wild type. Yellow arrow: the shape of the lateral petal in k mimics that of the ventral petal. Blue arrow: the retarded dorsal petals in lst1. Dashed lines: IN asymmetry of lateral and ventral petals is lost in syp1-1. The blue, orange, and yellow color marks the different cell types in dorsal, lateral, and ventral petals, respectively. DP, dorsal petal; LP, lateral petal; VP, ventral petal. (Scale bar, 50 μm.)