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		2. Vascular tissue(transport, support)35.11, 35.10 Vascular tissuetransports materials up and down between the roots and shoots. It is located at or towards the center of the root or stem. a. xylem i. tracheids ii. vessel elements The xylemtransports water from the roots up. . In order to move water, you need a tube. At functional maturity, the cells of the xylem reinforce their cell walls for strength and die, leaving a hollow tube, like a straw. The water flows through what used to be the inside of the cell, and passes between cells through pits, which are regions contaning lots of plasmadesmata. Tracheidsare the "oldest" type of water transporting cell, and the only kind found in gymnosperms. They contain hardened secondary cell walls and also provide support. Tracheids make up most of the cross-sectional area of the stem of a gymnosperm. Angiosperms contain both tracheids and vessel elements, which are shorter and wider. Vessel elements also contain hardened secondary cell walls. The cells are connected end-to-end, and the end walls are perforated to allow easier water movement.
			b. phloem i. seive-tube member ii. companion cells
		The phloemtransports nutrients throughout the plant. Unlike the xylem, the mature cells of the phloem (sieve tube members) still contain cytoplasm surrounded by a plasma membrane, so they are "alive" in some senses. However, they are missing a nucleus and most organelles. They are connected end-to-end to the next sieve tube member by a porous sieve platecontaining lots of plasmadesmata to allow for transfer. They are also connected to companion cells, small nucleated cells that supply proteins and other cell components to the sieve tube members. The companion cell and sieve tube members are sister cells. They arose from a