Root vascular tissue system
XYLEM: Primary xylem arms radiate from the center of the root and vary in number. The dicot types include diarch (2 arms), triarch (3 arms) or tetrarch (4 arms, see red circle below), and the monocot type is polyarch (many arms). Several types of cells, living and nonliving, make up xylem tissue. Tracheary and vessel elements conduct water and nutrients. Fibers provide support and living parenchyma cells store food. In monocots, vessel elements whose walls have been stretched and broken by elongation, result in spaces known as lacunae.
BORDERED PITS: The primary walls of tracheids and vessel elements have depressions called pit fields.
Return to Menu Page