Vascular Tissue: Xylem and Phloem The first fossils that show the presence of vascular tissue date to the Silurian period, about 430 million years ago.
The simplest arrangement of conductive cells shows a pattern of xylem at the center surrounded by phloem.
Together, xylem and phloem tissues form the vascular system of plants .
Xylem is the tissue responsible for supporting the plant as well as for the storage and long-distance transport of water and nutrients, including the transfer of water-soluble growth factors from the organs of synthesis to the target organs.
The end walls, unlike vessel members in xylem, do not have large openings.
Xylem and phloem form the vascular system of plants to transport water and other substances throughout the plant.