 Lecture Directory |
There are two transport systems in Secondary Xylem & Phloem. The Axial System is comprised of cells which are elongated parallel to the Long Axis of Growth. Secondary Xylem is part of the axial system. It is a complex tissue which can contain Tracheary Elements, Fibers and Axial Parenchyma. These cells are designed for Longitudinal Transport and Structural Support.
The Rays constitute the Radial System. These contain Parenchyma cells which are elongated Perpendicular to the long axis of the stem or root. They are designed for lateral transport. Rays can contain several kinds of parenchyma cells, tracheids and secretory structures but they are simple compared to the axial system.
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Axial and Radial components of Secondary Xylem. Cells with the largest diametyers are Vessels |
A Vessel seen in a Long Section. This is clearly part of the Axial System in the Xylem |
