Plant Cell Organisation

• leaf structure

  A) waxy cuticle

  B) upper epidermis

  C) palisade mesophyll

  D) spongy mesophyll

  E) lower epidermis

  F) stomata

  G) guard cells

  H) xylem and phloem

  
• function of structures

  • epidermal tissue - covers whole plant
  • palisade mesophyll tissue - photosynthesis
  • spongy mesophyll tissue - gases to diffuse
  • xylem and phloem - transpiration and translocation
  • stomata - co2 diffuse
  • guard cells - control stomata size
• xylem

  • transpiration
  • made up of dead cells
  • strengthened by lignin
  • carry water and dissolved mineral ions
  • flows in one direction
• phloem

  • translocation
  • elongated living cells
  • small pores in walls
  • transports food substances
  • flows in both directions
• transpiration

  • loss of water in plants
  • the rate is affected by - temperature , humidity, airflow, light