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• A vascular plant consists of a shoot system and a root system
• Shoot system


  • Contains supporting stems, photosynthetic leaves, and reproductive flowers
  • Contains repetitive units consisting of internode, node, leaf, and axillary bud

  
• Root system


  • Anchors the plant
  • Used to absorb water and ions
• Protoplast


  Entire cell excluding the cell wall
• Plant cell types


  • Differ in size of vacuoles
  • Differ in thickness of secretions found in their cellulose cell walls
  • May be living or not at maturity

  
• Cellulose fibers are parallel to microtubules

  
• Basic tissue types


  • Dermal
  • Ground
  • Vascular
• Tissue systems


  Extend through the root and shoot systems
• Meristems


  • Clumps of small cells with dense cytoplasm and large nuclei
  • Act as stem cells do in animals
  • One cell divides producing a differentiating cell and another that remains meristematic

  
• Apical meristems


  • Produce an extension (in length) of shoot and root
  • Composed of delicate cells that need protection

  
• Leaf primordia and root cap


  • Shelter and protect shoot and root apical meristems respectively

  
• Primary meristems


  • Protoderm
  • Procambium
  • Ground meristem
• Intercalary meristems


  Arise in stem internode and add to internode length
• Lateral meristems


  • Found in plants that exhibit secondary growth
  • Give rise to secondary tissues

  
• Cork cambium and vascular cambium


  Produce secondary tissues in woody plants

  
• Apical meristems produce the primary plant body, while lateral meristems produce an increase in the girth of a plant (secondary growth)

  
• Main plant tissue types


  • Dermal
  • Ground
  • Vascular
• Dermal tissue


  • Forms the epidermis
  • One cell layer thick in most plants
  • Covered with a waxy cutin layer constituting the cuticle
  • Contains guard cells, trichomes, and root hairs
• Guard cells


  Paired sausage-shaped cells that flank a stoma (epidermal opening)
• Trichomes


  Cellular or multicellular hairlike outgrowths of the epidermis
• Root hairs


  Tubular extensions of individual epidermal cells that greatly increase the root's surface area and efficiency of absorption

  
• Ground tissue cell types


  • Parenchyma
  • Collenchyma
  • Sclerenchyma
• Parenchyma


  • Most common type of plant cell
  • Living protoplasts that may live many years
  • Function in storage, photosynthesis, and secretion

  
• Collenchyma


  • Provide flexible support for plant organs
  • Have thickened primary walls
  • Allow bending without breaking
• Sclerenchyma


  • Have tough thick walls
  • Usually lack living protoplasts at maturity
  • Secondary cell walls often contain lignin
  • Include fibers and sclereids
• Vascular tissues


  • Xylem
  • Phloem
• Xylem


  Conducts water and dissolved minerals throughout plant
• Phloem


  • Conducts a solution of carbohydrates (mainly sucrose) used by plants for food
  • Also transports hormones, amino acids, and other substances necessary for plant growth
• Xylem cells


  • Vessels: Continuous tubes of dead cylindrical cells arranged end-to-end
  • Tracheids: Dead cells that taper at the end and overlap one another
• Phloem cells


  • Sieve cells (seedless vascular plants and gymnosperms) and sieve tube member cells (angiosperms)
  • Living cells containing no nuclei but containing clusters of pores called sieve areas or sieve plates
  • Associated with companion cells
• Monocotyledons (monocots) and Dicotyledons (Dicots, most of which are Eudicots) are the two groups of flowering vascular plants (angiosperms)
• Cotyledon


  The embryonic leaf in seed-bearing plants, one or more of which are the first to appear from a germinating seed

  
• Regions of the root


  • Root cap
  • Zone of cell division
  • Zone of elongation
  • Zone of maturation
• Root cap


  • Contains columella cells and root cap cells
  • Functions mainly in protection of the delicate tissues behind it
  • Also in the perception of gravity
• Zone of cell division


  • Derived from rapid divisions of the root apical meristem
  • Contains mostly cuboidal cells, with small vacuoles and large central nuclei
  • Daughter cells of apical meristem soon subdivide into the 3 primary tissues

  
• Zone of elongation


  • Roots lengthen because cells become several times longer than wide
  • Width also increases slightly
  • Mature parts of the root, except for increasing in girth, remain stationary for the life of the plant

  
• Root Cap


  Contains two types of cells that are formed continuously by the root apical meristem: Columella cells (inner) and Root cap cells (outer and lateral)

  
• Root Cap


  • Functions mainly in protection of the delicate tissues behind it
  • Also in the perception of gravity
• Zone of Cell Division


  • Derived from rapid divisions of the root apical meristem
  • Contains mostly cuboidal cells, with small vacuoles and large central nuclei

  
• Zone of Cell Division


  1. Daughter cells of apical meristem

  2. Apical meristem daughter cells soon subdivide into the 3 primary tissues: Protoderm, procambium, and ground meristem