Plant Tissue Systems: Vascular TissueXylem and phloem throughout the plant make up the vascular tissue system. They allow water and other nutrients to be transported throughout the plant. Xylem is consists of two types of cells known as tracheids and vessel elements. Tracheids and vessel elements form tube-shaped structures that provide pathways for water and minerals to travel from the roots to the leaves. While tracheids are found in all vascular plants, vessels are found only in angiosperms.
Phloem is composed mostly of cells called sieve-tube cells and companion cells. These cells assist in the transport of sugar and nutrients produced during photosynthesis from the leaves to other parts of the plant. While tracheid cells are nonliving, sieve-tube and companion cells of the phloem are living. Companion cells possess a nucleus and actively transport sugar into and out of sieve-tubes.