a vascular tissue in land plants primarily responsible for the distribution of water and minerals taken up by the roots; also the primary component of wood.
water and nutrients are moved through a plant by its vascular system. this consists of two types of microscopic tubes—xylem and phloem. xylem carries water and minerals from the roots to the rest of the plant. phloem carries nutrients, such as glucose, from where they are made to other parts of the plant. factmonster.com
in these plants water is absorbed by the roots and carried to the leaves by the xylem, and carbon dioxide is obtained from air that enters the leaves through the stomata and diffuses to the cells containing chlorophyll. the green pigment chlorophyll is uniquely capable of converting the active energy of light into a latent form that can be stored (in food) and used when needed. infoplease.com