The structure in plants responsible for water transport is called xylem. Xylem is a type of vascular tissue that conducts water and dissolved minerals absorbed by the roots of plants up to the leaves. This transport occurs through a combination of root pressure and the process of transpiration, where water evaporates from leaf surfaces, creating a negative pressure that pulls water upward. Proper functioning of xylem is crucial for plant health, as it facilitates nutrient distribution and maintains hydration levels in plant cells.