Transport systems- plants

• The main organs in a plant are the leaves, roots and the stem
• Waxy cuticle - prevents water loss

  Upper epidermis - allows light to pass through and prevent water loss

  Palisade mesophyll - main cells involved in photosynthesis

  Spongy mesophyll - contains air space to allow gas exchange

  Guard cells - contains the opening and closing of the stomata

  Stomata - air spaces that allow oxygen and water to leave and carbon dioxide to enter the leaf

  
• A plant obtains water through it's roots using the process of osmosis

  Roots contain specialised cells called root hair cells

  Plant root hair cells absorb the water and it moves up the xylem vessel and into the leaf area.

  These cells increase the surface area in which the plat can absorb water and nutrients from the soil

  
• Water and minerals are transported up through the plant stem by the xylem vessels

  Xylem is a tissue consisting of dead hollowed out cells that form a system of pipes.

  These dead xylem vessels are lignified and contains rings of lingnin. This allows the xylem vessel to withstand the pressure changes as water moves throughout the plant

  
• Sugar is transported up and down the plant in living phloem tissues.

  Phloem cells have sieve plates and companion cells to allow sugar to be transported to all parts of the plant.

  Companion cells provide the energy for the sieve cells . The end walls of the sieve plates have pores through which sugar can be transported from cell to cell.

  
• Transpiration is the loss of water from the leaves of plants.

  Water evaporates from the stomata in the leaf, this causes pressure changes within the plant meaning more water is drawn through the plant from the roots and back into the leaves

  A potometer can be used to investigate the rate of transpiration
• Environmental factors that can affect the rate of transpiration

  • increase in humidity -> decreases the rate of transpiration
  • increase in temperature -> increases the rate of transpiration
  • increase in wind speed -> increases the rate of transpiration
  • increase in surface area -> increases the rate of transpiration