Basic Morphology by cWw68Ksg

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									           Basic Morphology
• Morphology = external body form
• Anatomy = internal structures
• Monocot/dicot comparison
• How do roots and shoots reflect the
  evolutionary history of plants as terrestrial
  organisms?
• Plants live in 2 very different environments at
  the same time; air and soil
• Roots dig underground for water and
  minerals
• Shoots are above ground with adaptations
  for gas and light retrieval
                 Roots
• Anchors plant
• Structures for absorption of water and
  minerals
• Food storage
• Examples:
• Fibrous root
• Tap root
• Root hairs
        Stem Morphology
• Nodes – points where leaves attach
• Internodes – stem segment between
  nodes
• Axillary bud – usually dormant
  embryonic bud
• Terminal bud – bud on shoot tip usually
  has developmental leaves
• What is apical dominance?
• Why do plant owners pinch back
  houseplants?
        Modified stems
• Stolons
• Rhizomes
• bulbs
                 Leaves
•   Flattened blades
•   Petioles – joins leaf to stem node
•   Monocot leaves have parallel veins
•   Dicot leaves have multi-branched veins
                Anatomy
• Parnechyma cells
  – Most abundant cell type
  – Unspecialized
  – Thin primary cell walls
  – Photosynthesis and storage
  – Some store starch
• Collenchyma cells
  – Thick primary cell wall
  – Lack secondary cell walls
  – Functions in support for young plant (no
    lignin)
• Sclerenchyma Cells
  – Support
  – Thisk secondary celll walls stregnthened by
    lignin
    • Fibers
    • Sclerids
• Tracheids and Vessel elements
  – Xylem cells
  – Functionally dead at maturity
  – Tracheids are long and thin
  – Vessel elements are wider and shorter and
    better at conducting water (in angiosperms)
• Sieve Tube Members (alive)
  – Transports sucrose and other compounds
  – Chain of cells called phloem
• Companion cells
  – make proteins for sieve tube member
  – Help load sugar into the sieve tube
    members
           Tissue systems
• Dermal tissue:
• Epidermis
  – Protection
  – Waxy cuticle
  – Root hairs
  – Houses guard cells in the leaf
• Vascular tissue
  – Xylem and phloem
  – Transport functions
• Ground tissue system
  – Mostly parenchyma that fills space
    between dermal and vascular tissue
    system
  – Diverse functions:
    • Photosynthesis
    • Storage
    • support
             Meristems
• Why do most plants grow throughout
  their lives?
• Animals move through their
  environments, plants grow
• Meristem locations determine growth
   Which growth
involves the lateral
   meristems?
Primary Growth of Roots
Shoot Growth
Stem cross secitons:
                  Leaves
•   What is the ground tissue of the leaf?
•   Mesophyll
•   How is the mesophyll arranged?
•   Spongy and pallisade regions
        Secondary growth
• Growth in girth
• Two lateral meristems:
  – Vascular cambium
  – Cork cambium
• Secondary xylem accumulates while
  secondary phloem is sloughed off
For a good review of roots click here

For a good review of leaves click here

								
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