Root section. Coloured scanning electron micrograph (SEM) of a section through a root of a dicotyledon plant. The vascular bundle (yellow cluster, centre left) consists of xylem (large openings) and phloem (surrounding the xylem) tissue. Xylem transports water and mineral nutrients from the roots throughout the plant and phloem transports carbohydrates and plant hormones around the plant. Surrounding the vascular bundle is the cortex (cream), which consists of parenchyma cells, and then the outer epidermis (brown). Magnification: x100 when printed 10 centimetres wide.