Vascular bundle. Coloured scanning electron micrograph (SEM) of a section through a vascular bundle from a rootlet of a dicotyledon plant. The vascular bundle consists of xylem (orange) and phloem (pink) 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 single layer of endodermis (purple) and then cortex (brown), which consists of parenchyma cells.