Module 9: Plant Tissue

• Main groups of plant tissues

  • Protective tissue
  • Meristematic tissue
  • Mechanical tissue/Ground tissue
  • Conducting tissue
• Protective tissue


  • Covers the surface of the leaves & the living cells of the roots and stems
  • Cells are flattened with their top and bottom surfaces parallel
• Epidermis


  Plant’s “skin”
• Epidermis


  • Single layer of closely packed cells
  • Covers and protects the plant
• Periderm


  Also called “Bark”
• Periderm


  • Replaces the epidermis in plants that undergo secondary growth
  • Consists of cork cells
• Cork Cells


  • Protects the plant from pathogens
  • Prevents excessive water loss
  • Provides insulation in plants
• Meristematic tissue


  • Tissues where cells are constantly dividing
  • This is the region that produces new cells
  • Generally small, six sided boxlike structures with tiny vacuoles & large nucleus
• Types of Meristematic tissue

  • Apical Meristems
  • Lateral Meristems
  • Intercalary Meristems
• Apical Meristems


  • Can be near the tip of shoots and roots in plants
  • Primary Growth: increase in length (vertical growth)<>Produces embryo leaves & buds
• Lateral Meristems


  • Secondary Growth: increase in width (horizontal growth)
• Vascular Cambium

  “Cambium”
• Vascular Cambium


  • Thin, branching cylinder
  • Responsible for the production of cell tissue that increases the thickness of plants
• Cork Cambium


  • Thin, branching cylinder responsible for the production of bark
• Intercalary Meristems


  • Found in grasses & related plants that do not have vascular cambium and/or cork cambium
  • Actively producing new cells & responsible for the increase in length
• Ground Tissues


  • “Mechanical tissues”
  • Synthesizing organic compounds
  • Support the plants
  • Provides storage
• Types of Ground Tissues

  • Parenchyma
  • Collenchyma
  • Sclerenchyma
• Parenchyma


  • Most abundant cell types
  • Spherical and flattened
  • Can divide if they mature & is vital in repairing damaged plant tissues
• Chlorenchyma


  • Parenchyma cells which contain chloroplast and form the tissues found in leaf
• Chlorenchyma


  • Main function is for photosynthesis
• Aerenchyma


  • Tissue with cells loosely packed together with connected air spaces
• Collenchyma


  • Found just beneath the epidermis
  • Generally elongated and walls are pliable
  • Provides flexible support for organs
• Sclerenchyma


  • Have thick, rough secondary walls that are embedded with lignin
  • At maturity, most are dead and function in structure and support
• Vascular Tissues


  • Conducting tissues mainly for conducting water and nutrients
• Types of Vascular Tissues

  • Xylem
  • Phloem
• Xylem

  • Water-conducting
• Phloem


  • Conducts food and minerals
• Specialized Tissues


  • Stomata
  • Trichomes
• Stomata


  • Microscopic pore on the surface (epidermis) of plants
• Trichomes


  • Cutinized epidermal appendages found in the leaf, stem, flower and fruit
  • Protect and prevent water evaporation