Cucumber vascular bundle. Light micrograph of a cross section through a cucumber stem (Cucumis sativus). The vascular system is made up of xylem (larger spaces at top), which transports water and nutrients from the roots to the leaves, and phloem (pink circular spaces), which transports food (sugar) to the roots and the stem. The phloem is made up of sieve tube members that connect at specialized areas known as sieve plates (blue). Sieve plates consist of tiny pores which enable materials to flow from one sieve tube member to another. Magnification X102 when printed 10 centimetres wide.