plants 1

• Plant tissues


  • Dermal
  • Meristematic
  • Ground
  • Vascular
• Components of plant tissues

  • Parenchyma
  • Collenchyma
  • Sclerenchyma
  • Xylem
  • Phloem
  • Vascular cambium

  
• Plant tissues


  • Dermal - provides protection

  Meristematic - found at growing tips

  Ground - 3 types: Parenchyma, Collenchyma, Sclerenchyma

  Vascular - 2 types: Xylem and Phloem

  
• Parenchyma


  Most common type, living cells found in leaves/tubers, involved in photosynthesis and food storage, thin walls and large vacuoles

  
• Collenchyma


  Living cells that provide structural support, have thick walls

  
• Sclerenchyma


  Non-living cells that provide support and rigidity, have thick walls

  
• Xylem


  Moves water and nutrients up the plant, from roots through stems to leaves, consists of non-living tracheids and vessel elements
• Phloem


  Moves sugar and water solution from leaves to other parts of the plant, consists of living sieve tube elements and companion cells
• Vascular cambium


  A ring of actively dividing cells found separating the xylem and phloem, cell divisions result in formation of secondary xylem and secondary phloem
• Vascular cambium permits secondary (lateral) growth
• Growth rings in trees are due to the activity of the vascular cambium
• The study of tree rings is called dendrochronology
• Plants have shoots that grow above ground and roots that grow below ground
• Shoots consist of a stem and leaves, and bear flowers and seeds

  
• Roots may function as storage organs and are most important for absorption of water and nutrients, they create a large surface area
• Leaves are the primary site for photosynthesis, where sugar is formed from carbon dioxide and water and oxygen is produced
• Leaves have an upper epidermis and a lower epidermis, with mesophyll cells (palisade and spongy) in between
• Leaves have a cuticle on the surface that contains waxes (hydrophobic) that reduces water loss (transpiration)
• Stems provide physical support to the plant and are also involved in movement of water and nutrients up the plant through the vascular system (xylem and phloem)
• Stems allow for continued growth through the apical meristem and contain axillary buds that give rise to side shoots

  
• Stems can be used for storage of food and water, and allow for lateral growth to increase width
• Meristems are actively growing regions found at the tips of shoots and roots of plants that allow for continued growth

  
• Growth of side shoots from stems is due to axillary bud meristems, and lateral growth of stems is due to lateral meristems, especially cambium

  
• Roots anchor the plant/tree in the soil, absorb water and nutrients, and have a large surface area due to root hairs
• Continued root growth occurs through the root meristems, and roots can be used for storage of nutrients