Structure of flowing plants

• Plants are divided into two portions

  Overground shoot system and underground root system
• Meristem 


  An area of active cell division

  • apical meristems are found at the tip of the shoot and tip of the root and give an increase in length
  • lateral meristems are found around the edges of some plants and give an increase in width
• Root functions

  • Anchor plant
  • absorb water
  • absorb minerals
  • transport absorbed minerals to shoot
  • store food
• Tap root


  One main root growing from radicle (first root that Grows from the seed) lateral root grow out from the main root eg carrots
• Fibrous root


  Many equal sized roots arising from the base of the stem eg grass
• Zone of differentiation


  Here cells developed into three types of tissue

  1. Dermal tissue
  2. Ground tissue
  3. Vascular tissue
• Zone of elongation


  Here cells increase in size

  
• Zone of cell production or meristematic zone


  here new cells are produced by mitosis divisions
• Zone of protection


  A root cap protects the cell as the root pushes through the soil

  
• Tissue location in the root (transverse section)

  
• Tissue location in the root (longitudinal section)

  
• Stem functions

  1. Supports the aerial parts of the plant
  2. Transport water and minerals from roots to the leaves
  3. Transport food from leaves to roots
  4. Sometimes store food, e.g. celery
• Function of outer stem parts

  • Terminal bud (apical)

  increase stem length

  • lateral bud (axillary)

  grow side branches

  • lenticles

  openings in the stem for gas exchange
• Tissue location in the stem

  Transverse section

  
• Tissue location in stem

  Longitudinal section

  
• Leaf functions

  1. Photosynthesis
  2. transpiration
  3. gas exchange
  4. sometime store food
• Vertical section of a leaf, internal structure

  
• Leaf parts

  • Petiole: stalk that joins a leaf to the stem
  • Node: where leaf is attached
  • veins contain vascular tissue

  
• Pattern of veins (venation)

  • Parallel: veins run alongside each other, e.g. daffodils
  • net: veins form a branching network through the lamina (leaf blade)
• Flower function


  Sexual reproduction
• Vascular tissue

  1. Xylem- transports water and minerals
  2. phloem- transport food
• Xylem structure 


  On maturity, both are dead, hollow and contain no cytoplasm
• Xylem tracheid structure

  • Long cell tapered at both ends
  • pits in the walls, allow water and minerals to move sideways from cell to cell
  • Wall thickened with lignin for support

  
• Xylem vessels structure

  • Elongated cells
  • Spiral lignin for strength
  • No end walls, form a continuous tube
  • Pits to allow sideways movement of water

  
• Phloem structure

  1. Sieve tube cells

  mature cells have no nucleus, sieve plates

  cytoplasm extends fro, cell to cell through sieve plate

  2. companion cells

  nucleus controls activities of both companion and sieve tube cells

  
• longitudinal ans transverse sec

  
• Monocot- grass

  dicot- buttercups
• Monocots

  • Cotyledons: 1
  • arrangement of vascular bundles in stem: scattered in stem
  • leaf venation: parallel
  • number of flower plants: in threes
  • woody/herbaceous: almost all herbaceous
• Dicots

  • cotyledons: 2
  • arrangement of vascular bundles in stem: in a ring pattern
  • leaf venation: netted
  • number of flowering plants: 4/5
  • woody/ herbaceous: may be either
• Monocots and dicots