Dicotyledon vascular bundle. Coloured scanning electron micrograph (SEM) of a section through a vascular bundle from a dicotyledonous plant. The vascular bundle, which consists of xylem (yellow) and phloem (red) tissues. Xylem transports water and mineral nutrients from the roots throughout the plant and phloem transports carbohydrate and hormones around the plant. Magnification: x400, when printed 10 centimetres wide.