Figure 1.

Cellular identities in the petal epidermis. (A) Half-flower from Petunia x hybrida, cut open longitudinally to display the tube and limb regions (scale bar=1cm). The contour of one petal is shown with a white dotted line. Proximo/distal and adaxial/abaxial polarities of the petal are indicated with blue arrows. Scanning electron micrographs (scale bars=20μm) of the adaxial surface of petals in the limbs, and at three different regions from the tube, indicated by green arrows and numbers in the flower picture. These pictures were obtained with a HIROX SH-1500 bench top environmental scanning electron microscope equipped with a cooling stage (−10°C, 5kV). (B) Petal from Nigella arvensis viewed from its adaxial side (scale bar=1mm), with nine regions with different cellular identities as identified in Yao et al. (2019). A 10th region is only visible on the abaxial side of the petal. Scanning electron micrographs of cells from five of these regions, giving an overview of cellular diversity in this organ (scale bars=10μm). Region 8: conical cells; region 5: short trichomes; region 4: oblong cells; region 7: polygonal cells with smooth surfaces; region 3: secretory cells. Pictures are reproduced from Yao et al. (2019) with permission from the authors.