Dicotyledonous Root

• External Structure?

  • Root cap - protects & surrounds the growing plant.
  • Meristematic region - forms new cells.
  • Region of elongation - where new cells elongate.
  • Root hair region - characterised by unicellular root hairs that increase the absorption surface of the root.
  • Mature region - lateral roots develop and branch off, increasing the absorption surface and anchors the plant.
• Internal Structure?

  Epidermis

  • forms the outer layer of the stem.
  • cuticle is absent.

  Cortex

  • a broad band under the epidermis that consists of parenchyma cells, with large intercellular spaces.
  • the innermost layer of the cortex is the endodermis.

  Central Cylinder

  • all tissues enclosed by the endodermis.
  • under the endodermis, there are layers called the pericycle.
  • xylem - x shape.
  • phloem - p shape.
  • the rest of the central cylinder has parenchyma cells.
• Functions of tissues in the root?

  Root hairs

  • increase the absorption surface for the uptake of water & minerals.

  Epidermis

  • protects underlying tissues.

  Parenchyma

  • allows water and minerals to pass through to the xylem.
  • stores starch.

  Endodermis

  • Regulates the passage of water from cortex to xylem.

  Pericycle

  • Forms lateral roots

  Xylem

  • transports water and minerals from the root to the rest of the plant.

  Phloem

  • Transports food from the leaves to the rest of the plants.
• Root functions?

  • Absorbs water and minerals from the soil.
  • Anchors the plant in the soil.