New to the Illustrated Glossary: Vascular Bundle and Vein

by Mary Free and Christa Watters, Extension Master Gardeners

Curious how the sugars produced during photosynthesis move from a plant’s leaves to elsewhere in the plant or how water and minerals move from a plant’s roots to its shoots? Do you know how plants without leaves—like cacti—produce sugars or that cacti taste sweeter if they are harvested mid-morning to mid-afternoon? To learn the answers to these questions and more, visit our newest Illustrated Glossary terms: vascular bundle and vein.

What are vascular bundles? In a plant’s vascular system, fluids do not move in a loop or through tubes as it does in the human body, but rather from one end of the plant to the other through specialized cells—phloem  and xylem. Phloem cells deliver the products of photosynthesis. Xylem cells deliver the water and minerals absorbed by the roots. The phloem and xylem are always located next to each other. In leaves and stems, they form a structure called a vascular bundle. In a leaf, the veins are the vascular bundles.

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Clockwise from top left: Branching veins of Ficus carica (common fig) leaf, Ficus leaf cross section showing vascular bundle of the midrib, flow of fluids through the phloem and the xylem.

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