Index of Images in Part 2
This is an index of all the images in Part 2 except for the Cover image. If you want to review an image, you can click on the figure number and Title to bring up the full page on which it appears OR on the description to bring up just the single full image.
Figure 1. The flowering bean plant. The apex of a compact bean plant stem showing young flower buds (arrow).
Figure 2. The flowering bean plant. Flower buds forming in the axil of a young trifoliate leaf.
Figure 3. A longitudinal section through a preserved flowering bean plant. A longitudinal section through the stem terminal of a bean plant showing multiple flower buds (arrows) at the terminal of the stem. Slide preparation by Triarch Incorporated (Ripon, WI). Used with permission. Magnified 50 times.
Figure 4. The flowering, vining bean plant. These pale pink buds and flowers don’t open like the flowers of other types of plants and each part has a special name (i.e., wings, keel, banner). This is typical of plants in the bean and pea family.
Figure 5. A close-up of a flowering bean plant. Note the trichomes on the stem (blue arrow) and leaflet margin (yellow arrow).
Figures 6 and 7. The floral parts of a bean plant. Within each flower bud (Fig. 6), the reproductive parts of the bean plant have formed (Fig. 7). They are the stamens (yellow arrow) and pistil (white arrows). Both magnified 24 times.
Figure 8. The reproductive parts of a bean plant. The ovary (at the base of the pistil; yellow arrow) swells once fertilization occurs. The stigma (blue arrow) and style (white arrow) of the pistil will eventually die and fall off. Magnified 9 times.
Figure 9. Parts of a bean flower. Flowers never open fully. In this photo, on one flower, you can identify the wings (yellow arrow) and the banner (blue arrow). On the lower flower you can see the keel (white arrow).
Figure 10. The flowering bean plant. One flower shows a developing bean seed pod (arrow).
Figure 11. Within the seed pod. These are the fertilized ovules within the ovary which become 1 seed pod. Each ovule will grow into a red kidney bean seed. Magnified 37 times.
Figure 12. Young seed pods. As time progresses, more and more flowers senesce (die) and reveal young seed pods.
Figure 13. Within each seed pod, bean seeds are developing. This photo, taken on day 32, captures the young bean within the pod. Magnified 36 times.
Figure 14. Bean plant root. A longitudinal section through the root of a red kidney bean plant. This whole mount viewed longitudinally (through the stereo microscope) shows the epidermis (yellow arrow), the meristem (circle) and root cap (blue arrow) of the root. Magnified 40 times.
Figure 15. The root hairs on a bean plant root. Bean plant root hairs (arrows). Magnified 100 times.
Figure 16. The root hairs on a bean plant root. A root hair (arrow) is an expanded epidermal cell. Magnified 200 times.
Figure 17. The bean plant root. A cross-section through a very young bean plant root. Magnified 36 times.
Figure 18. A cross-section through a bean plant root. Since you can identify the tissues using colored stains, you know this is a mature bean plant root. Note the star shape (yellow) of the xylem in the center of the root. Magnified 100 times.
Figure 19. A cross-section through a bean plant root. This is a closer view of the xylem which is the plant’s water and nutrient conducting tissue (yellow arrow). The xylem contains living and non-living (dead) cells. There are four branches (poles) of xylem that make up the star shape. There is more xylem than phloem (white arrow). Phloem is the ‘food’ conducting tissue. Magnified 200 times.
Figure 20. A light microscope view of an emerging bean plant root. A branch root (arrow) is emerging from the main root. As the main root matures, more xylem tissue develops. Slide prepared by the Nebraska Veterinary Diagnostic Center. Magnified 50 times.
Figure 21. SEM of a bean plant root. Vessels (arrows) are the large water/nutrient conducting tubes of the xylem.
Figure 22. A low magnification view of a cross-section of a bean plant stem. A cross-section (transverse section) through the main stem of a bean plant showing secondary growth. The center tissue is the pith (white arrow). The next layer of dark green tissue is the initial vascular bundles (yellow arrow) and the pale green tissue is the recent maturing xylem (blue arrow) and the dark green band (red arrow) is the cortex. Taken Day 58. Magnified 33 times.
Fig. 23. SEM of a bean plant stem. In this scanning electron microscope view, the pith (yellow arrow) appears empty and secondary xylem (white arrow) is more easily recognizable. The large holes are vessels and the small holes are tracheids or tracheary elements. Both are part of the xylem tissue. Note that the shape of the stem is circular.
Figure 24. A cross-section of a bean plant stem. In this cross-section, you can see the cortex (yellow arrow) which is made up of living cells which contain chloroplasts. Chloroplasts give a plant its green color. The epidermis, which is often just a single cell layer, is also visible (blue arrow). You can also see that the cells in the pith contain something (white arrow). A higher magnification will help identify these bodies. Slide prepared by the Nebraska Veterinary Diagnostic Center. Magnified 50 times.
Figure 25. SEM of the tissues in a bean plant stem. This cross-section shows that the cortex (yellow arrow) which is made up of living cells is much smaller than the xylem. The epidermis is also visible in this 3-dimensional view (white arrow).
Figure 26. SEM of the pith in a bean plant stem. These are the cells of the pith. Note that they are hexagons (6-sided). Thanks to this magnification, starch grains (arrow) are identifiable. To be sure these are starch grains, a stem can be stained with potassium iodide solution. If it turns blue/black, then there are starch grains present.
Figure 27. The branch stem of a bean plant. Note the clear pith in the center and the hexagonal shape. Magnified 48 times.
Figure 28. SEM of a branch stem of a bean plant. Note the hexagonal shape of the branch stem and the presence of trichomes (arrow).
Figure 29. A close-up SEM of a branch stem. Note the pith (yellow arrow), xylem (blue arrow) and epidermis (red arrow) with trichomes.
Figure 30. A high magnification SEM of a branch stem. Note the pith (yellow arrow). The cells of the xylem (blue arrow) include vessels, tracheids and tracheary elements (dead, strong cells) as well as parenchyma cells which are the same live cells as in the pith.
Figure 31. Starch grains in the pith of a bean stem. Plants produce sugars via the process of photosynthesis. Any sugars that are not immediately used by respiration may be stored in the cell as starch.
Figure 32. A close-up of starch grains in the pith of a bean stem. Staining a plant stem with iodine is a way to determine if starch is present. A drop of potassium iodide will turn dark blue/black when it encounters starch.
Figure 33. Draw what you see! This hand drawing demonstrates that looking at a leaflet section through the microscope can also be captured by drawing the image. Trichome (black arrow), upper (adaxial) leaflet epidermis (blue arrow), palisade mesophyll (yellow arrow), spongy mesophyll (white arrow) and lower (abaxial) epidermis (red arrow).
Figure 34. Light microscope view of a bean leaf. A thick cross-section through a bean leaflet showing the adaxial epidermis (blue arrow), palisade mesophyll (yellow arrow), spongy mesophyll (white arrow), abaxial epidermis (red arrow) with hooked trichomes (black arrow). The green color shows the chloroplasts. This section was made from a fresh green leaf. Magnified 100 times.
Figure 35. Higher magnification view of a cross-section of a bean leaflet. A thick cross-section through a bean leaflet showing the adaxial epidermis (blue arrow), palisade mesophyll (yellow arrow), spongy mesophyll (white arrow), abaxial epidermis (red arrow) with a trichome (black arrow). The green colors are chloroplasts. This section was made from a fresh green leaf. The star indicates an empty space where gas exchange can occur. Magnified 200 times.
Figure 36. Cross-section through a preserved leaflet stained with safranin and toluidine blue O. An even higher magnification of the cross-section through a bean leaflet showing the adaxial epidermis (blue arrow), palisade parenchyma (yellow arrow), spongy mesophyll (white arrow) and abaxial epidermis (red arrow). The blue discs are chloroplasts. Note the air spaces. Slide prepared by the Nebraska Veterinary Diagnostic Center. Magnified 125 times.
Figure 37. A cross-section through the midvein of a preserved bean leaflet. The midvein is the big, middle vein (midrib) in a bean leaflet. This cross-section shows the adaxial epidermis (blue arrow), palisade mesophyll (yellow arrow), spongy mesophyll (white arrow), abaxial epidermis (red arrow) and the midrib (black arrow). The midrib also contains a vascular bundle which contains xylem and phloem tissues. Slide prepared by the Nebraska Veterinary Diagnostic Center. Magnified 50 times.
Figure 38. A 3-dimensional view of the main big vein (midrib). The midrib runs down the center of a leaflet directly into a stem. This photo is of the middle leaflet of the third trifoliate leaf.
Figure 39. A closer view of the midrib. Note the trichomes (black arrows), adaxial epidermis (blue arrow), the xylem in the vascular bundle (yellow arrow) and the abaxial epidermis (red arrow) This is the midrib of the middle leaflet of the third trifoliate leaf.
Figure 40. A high magnification view of the xylem. A high magnification of vessels (water tubes) in the midrib of the middle leaflet of the third trifoliate leaf.
Figure 41. Trichomes on the upper surface (adaxial) of a bean leaflet. On red kidney bean leaves there are numerous trichomes, almost 20 per 1.00 mm2.
Figure 42. Trichomes on the bean leaflet lower surface (abaxial). Red kidney bean leaves have trichomes on both sides of the leaflets.
Figure 43. Trichomes on the midrib (adaxial). The midrib of the middle leaflet of the third trifoliate has straight and hooked trichomes.
Figure 44. SEM close-up of hooked trichomes. A closer view of the hooked trichomes which are about 1 µm wide. If you stroke the leaf gently, you can feel them!
Figure 45. The tip of a bean leaflet hooked trichome. The pointed tip is approximately 0.1 µm wide. Perfect for impaling small insects (ex. bed bugs are 4-7 mm in diameter).
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.
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.
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.
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?
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.
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.
Figure 52. Maturing bean pods. The bean pods are elongating and swelling as the seeds grow.
Figure 53. Early view inside a seed pod. This seed pod shows four seeds maturing.
Figure 54. Maturing bean seed pods. Seed pods will lengthen as they mature.
Figure 55. Pretty seed pods. Given the right light conditions, some seed pods get a dark pink mottled appearance.
Figure 56. The bean plant’s life cycle is complete. One of the beans (the fifth, on the right) did not mature. The rest of these beans can be cooked (do not eat raw beans) or planted to grow new bean plants.