Plant organisation ai book scan

• Plant Cell Organisation


  How plant cells are organised into tissues and organs
• Plant cells are organised into tissues and organs
• Plant organs work together to make organ systems
• Examples of plant tissues

  • Epidermal tissue
  • Palisade mesophyll tissue
  • Spongy mesophyll tissue
  • Xylem and phloem
  • Meristem tissue
• Leaf

  • Made up of epidermal, mesophyll, xylem and phloem tissues
• Epidermal tissue


  Covers the whole plant, has a waxy cuticle to reduce water loss
• Palisade mesophyll tissue


  Where most photosynthesis happens, has lots of chloroplasts
• Spongy mesophyll tissue


  Contains big air spaces to allow gases to diffuse in and out of cells
• Xylem and phloem


  Transport water, mineral ions and food around the plant
• Meristem tissue


  Found at the growing roots and shoots, can differentiate into many plant cell types
• Transpiration


  The loss of water from a plant
• Transpiration stream


  Water moves from roots, through xylem, and out of leaves
• Phloem


  Transports food substances, mainly dissolved sugars, to the rest of the plant
• Xylem


  Transports water and mineral ions from roots to stem and leaves
• Xylem vessels


  Carry water
• Phloem vessels


  Carry sugars
• Transpiration is a side-effect of leaves being adapted for photosynthesis
• Stomata allow gases to be exchanged, but also cause water to evaporate from leaves
• Factors affecting transpiration rate


  • Light intensity
  • Temperature
  • Air flow
• Light intensity


  The brighter the light, the greater the transpiration rate
• Temperature


  The warmer it is, the faster transpiration happens
• Air flow


  The better the air flow around a leaf, the greater the transpiration rate