Plant Organs: Roots

  1. Funciton of roots
    • Anchorage
    • Absorption of water and minerals from soil (assisted by root hairs)
    • Food storage in some
  2. Types of roots
    • Fibrous- no main root, highly branched
    • Taproot- one main root with many small branches
  3. Roots endodermis
    • Endodermis --- the innermost cortex layer
    • Specialized parenchymal cells whose lateral and tangential walls are embedded with suberin (Casparian strip)
    • Force water and minerals to enter cells , because the casparian strip inhibits movement between cells or in cell walls
  4. Roots pericycle
    • Pericycle
    • Gives rise to branch roots
  5. Herbaceous Dicot Roots Order
    • Epidermis with root hairs, no cuticle
    • Cortex
    • Endodermis with Casparian strip
    • Vascular Cylinder (= Stele)
  6. Herbaceous Dicot Roots Vascular Cylinder= stele
    • Pericycle
    • Xylem arranged in geometric array (star or cross) in center of root
    • Phloem wedges on outside of xylem in between xylem arms
    • No pith 
  7. Woody Dicot Roots
    Functions in support & anchorage, not absorption
  8. Woody dicot roots dermal and vascular tissue
    • Periderm (replaces epidermis)
    • Cork and cork cambium
    • Vascular Cambium produces secondary xylem toward the inside and secondary phloem toward outside
  9. Monocot Roots order
    • Epidermis with root hairs; no cuticle
    • Cortex- collenchyma and parenchyma
    • Endodermis with Casparian Strip
    • Pericycle
    • Outermost layer of stele
    • lateral meristem- gives rise to lateral roots
    • Vascular Stele
    • Xylem arranged in circular fashion with patches of phloem between
    • Pith
Card Set
Plant Organs: Roots
Plant Organs