Plant Tissue

• Photosynthesis takes place in leaves
• Leaf


  A plant organ
• Leaf


  • Contains different tissues
• Epidermal cells


  Form epidermal tissue
• Upper epidermis


  Covers the top of the leaf
• Lower epidermis


  Covers the bottom of the leaf
• Epidermis


  • Protects the surface of the leaf
• Upper epidermis


  • Transparent, allows light to pass through
• Waxy cuticle


  Thin layer of oily material covering the upper epidermis, reduces water evaporation
• Stomata


  Tiny pores in the lower epidermis, allow carbon dioxide in and oxygen out, help control water vapour loss
• Guard cells


  Found on either side of the stomata
• Palisade mesophyll


  Packed with chloroplasts, site of photosynthesis
• Spongy mesophyll


  Full of air spaces, allows gas exchange
• Xylem


  Transports water and dissolved mineral ions from roots to leaves
• Phloem


  Transports dissolved sugars produced by photosynthesis from leaves to rest of plant
• Translocation


  Movement of sugars through phloem tissue
• Meristem tissue


  Contains stem cells that can differentiate into different plant tissues, found in growing tips
• This diagram shows a cross section of a leaf

  A) cuticle

  B) upper epidermis

  C) chloroplasts

  D) vacuole

  E) xylem

  F) vein

  G) phloem

  H) lower epidermis

  I) cuticle

  J) air channel

  K) stoma

  L) guard cells

  M) spongy mesophyll

  N) vertical palisade cell