3.2-specialisation and organisation

• Plants have 2 systems

  • shoot above system
  • below root system
• merismatic tissues- they are plant tissues found in tips of roots and shoots that is made of unspecialised cells.
• permanent are plant cells that can no longer divide they include

  • dermal tissue
• dermal tissue protect the soft tissues of plants.
• ground tissue are all plant tissues that are not dermal or vascular. They include

  • parenchyma
  • collenchyma
  • Sclerenchyma
• parenchyma- the tissue of the plant that contains the living cells and is the site of photosynthesis and they are thin walled living plant cells.
• collenchyma- thick flexible walled cells in plants ( main supporting tissue of stems.)
• sclerenchyma- dead cells with thickened wall as for strength.
• vascular tissues have tissue including

  • xylem
  • phloem
• xylem: transport water and minerals and provides support.
• Phloem- complex plant tissue that transports sugars and other organic compounds
• root hairs are the extensions of outer cellular covering of the root and absorbs water.
• the 2 cells inside the xylem are called

  • tracheids
  • vessels
• trachieds are present in vascular plants, are long thin and tubular cells and have no contents ( not living)
• Vessels

  • found in flowering plants
  • lose cell contents and are dead
  • have perforation plates.
  • have primary and secondary cell wall ( like tracheids)
  • have area that is thin or absent which lets water exit it
• remainder of water is found in

  • air spaces
  • stomata
• the stomata are port surrounded by 2 guard cells that relegate the opening and closing of them.
• water moves from the xylem to the high leaves
• cohesion- water molecule sticking together thru hydrogen bonds
• adhesion- attraction of water molecules to other charged molecules
• Roots


  Anchor the plant in the soil and absorb water and nutrients
• Transpiration


  Process of water absorption by roots, movement through the plant, and release as water vapor through stomata
• Photosynthesis


  Process of making food using sunlight, carbon dioxide, and water, producing glucose and oxygen
• Stomata


  Small openings on plant leaves for gas exchange, intake of carbon dioxide, and release of oxygen and water vapor
• Dermal Tissue


  Protects the plant and reduces water loss
• Vascular Tissue


  Facilitates transport of water, nutrients, and sugars in the plant
• Ground Tissue


  Provides structural support and nutrient storage in plants