Stomata – another important cell type that is present on all leaves are stomata. The stomata are the organs that allow the plant to take in carbon dioxide and expel oxygen.
Figure 46. Stomata on a fresh bean leaflet. The abaxial epidermis showing stomata and trichomes (white arrows) on a fresh bean leaf. The puzzle piece cells are the subsidiary cells (blue arrows) and the two inner tube-like structures (black arrow) are the guard cells. The stomatal opening also called the stomatal pore is identified by the yellow arrow. Magnified 200 times. Credit: C.G. Elowsky
Figure 47. Day 49. Stomata and chloroplasts viewed using the light microscope. The abaxial of the middle leaflet of the third trifoliate leaflet showing stomata. If you peel off the lower epidermis of one of the leaflets, and view the peel under the light microscope, you can see stomata (arrows) and chloroplasts (green beads). Magnified 125 times. Credit: E.T. Paparozzi
Figure 48. Stomata on the adaxial surface of a bean leaf. The top surface (adaxial) of a bean leaflet also has stomata (arrows). However, they are fewer and harder to find. Credit: E.T. Paparozzi
Figure 49. Stomata on the abaxial of a bean leaf. Multiple stomata (arrow) on the abaxial leaflet surface of the middle leaflet of the third trifoliate leaf. Can you find seven stomata? Credit: E.T. Paparozzi
Figure 50. Four closed stomata on the abaxial of a bean leaf. Closed stomata (arrows) on the abaxial (bottom) leaflet surface of the middle leaflet of the third trifoliate leaf. Credit: E.T. Paparozzi
Figure 51. High magnification view of an open stoma. Close-up view of an individual, open stoma on the abaxial of the middle leaflet of the third trifoliate leaf. Credit: E.T. Paparozzi