DR KEITH WHEELER / SCIENCE PHOTO LIBRARY DR KEITH WHEELER / SCIENCE PHOTO LIBRARY
Sunflower leaf. Light micrograph of a transverse section through the midrib of a sunflower (Helianthus annuus) leaf. The upper and lower epidermis on the surfaces of the leaf are blue. Under the upper epidermis are palisade cells (yellow), which contain chloroplasts, the site of photosynthesis. Within the midrib is a ring of vascular bundles, composed of xylem (red) and phloem (dark blue) cells, which transport water and carbohydrates around the plant respectively. Magnification: x100 when printed at 10 centimetres wide.
Model release not available. Property release not required.