Plant Cell Organisation

• Plants are made from organs like stems, roots and leaves. These make organ systems which perform essential tasks like transporting substances around the plant.
• Epidermal Tissue


  Covers the whole plant
• Palisade mesophyll tissue


  On the leaf where the most photosynthesis happens
• Spongy mesophyll tissue


  On the leaf. Contains big air spaces for gas diffusion.
• Xylem and Phloem

  Transport water, mineral ions, and food.
• Meristem tissue


  found at the growing tips of shoots and roots. Is able to differentiate into lots of different types of plant cell, allowing the plant to grow.
• 1. The epidermal tissues are covered with a waxy cuticle- helps to reduce water loss by evaporation
  2. The upper epidermis is transparent- light can pass through into the palisade layer
  3. The palisade layer has lots of chloroplasts, so they're near the top of the leaf and get lots of light
  4. The xylem and phloem for a network of vascular bundles, which deliver water and nutrients to the entire leaf and take away glucose produced by photosynthesis. They also help support the structure.
  5. The tissues are efficient for gas exchange- lower epidermis is full of holes (stomata) for direct diffusion.
• Stomata

  • Little holes in the lower epidermis
  • Let carbon dioxide diffuse directly into the leaf
  • Opening and closing controlled by guard cells
• The air spaces in the spongy mesophyll tissue increase the rate of diffusion
• Label the diagram

  A) upper epidermis

  B) palisade mesophyll

  C) spongy mesophyll

  D) guard cells with chloroplasts

  E) lower epidermis

  F) waxy cuticle

  G) xylem

  H) air space

  I) phloem

  J) guard cells with chloroplasts