B2__Organsiation

Tissues in Leaves

The leaf is a plant organ that contains different tissues

Upper and Lower Epidermis

  • Layer of very thin cells
  • Protects surface of leaf
  • Transparent to allow light to pass through
  • Covered with waxy cuticle to reduce evaporation of water

Stomata

  • Pores in lower epidermis which allow carbon dioxide to enter the leaf and oxygen to leave.
  • Also control water vapour

Guard Cells

  • On either side of stomata are and open and close stomata

Palisade Mesophyll

  • Contains lots of palisade cells which contain lots of chloroplast for photosynthesis

Spongy Mesophyll

  • Full of air spaces allow carbon dioxide to diffuse from stomata through spongy mesophyll to palisade cells, oxygen diffuses from palisade through spongy mesophyll to stomata

Xylem

  • Transports water from roots to the stem and leaves some of which is used in photo synthesise, transports dissolved mineral ions

Phloem

  • Transport dissolved sugars produced by photosynthesis from leaves to the rest of the plant
  • Sugars are used in multiple ways

Meristem Tissue