Ash stem. Light micrograph of a transverse section through the woody stem of an ash (Fraxinus excelsior) tree showing four growth rings (concentric circles). The outer layer is composed of cork (blackish-brown),underneath which is the cortex (red-purple),with primary phloem fibres (light red bundles) in the inner cortex. Under this is a layer of phloem sieve tubes with simple sieve plates (dark blue and deep red). Under the phloem is a ring of cambium (deep blue) and under this is a thick layer of wood (xylem,red). The solid pith (centre) is composed of parenchyma cells. Magnification: x14 when printed 10 centimetres wide | |
Lizenzart: | Lizenzpflichtig |
Credit: | Science Photo Library / Wheeler, Dr. Keith |
Bildgröße: | 5687 px × 4581 px |
Modell-Rechte: | nicht erforderlich |
Eigentums-Rechte: | nicht erforderlich |
Restrictions: | - |