XYLEM

• Xylem is a type of complex tissue in vascular plants that transports water and minerals from roots to the leaves. The transport of water is through passive transport so that it doesn't need energy. The water moves through simple capillary action in the xylem and is called xylem sap.
• Tracheid's and vessel elements

  • Both elongated
  • Secondary structure
  • Non-Living at maturity
• Tracheids

  • No perforations
  • Imperforate cells having only pit-pairs on their common walls
  • In gymnosperms and primitive vascular plants
• Vessel Elements

  • Have perforations at end walls
  • Connected end-to-end
  • Major conducting cells in angiosperms
• Perforation plates of vessel elements:

  A)Simple

  B) Scalariform

  C) Formaninate

  D) Scalariform-reticulate

  
• Vessels are more efficient conduits of water than the tracheid's.
• The principal functions of Tracheary elements in the Axial System (such as Trachelds and Vessel elements) is the conduction of water and transport of solutes
• The principal functions of Fibers in the Axial System (such as Fiber-tracheids and Libriform fibers) is to support; sometimes storage.
• The principal functions of Parenchyma Cells in the Axial System and Radial System (such as The principal functions of Tracheary elements in the Axial System (such as parenchyma cells, and tracheids in some conifers) is food storage; translocation or various substance.