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Ch Plant Structure and Function

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					1.   Review What are the three main tissue systems of
     plants
2.   Compare and Contrast How do the three main
     functions of a plant’s tissue differ
3.   Form and Function How might the presence of
     meristems explain the ability of plants to
     regenerate from cuttings
4.   Infer With your prior knowledge of the circulatory
     system, write a paragraph comparing and
     contrasting the structure and function of the
     vascular system of a plant to the human
     circulatory system
CH 23 PLANT STRUCTURE AND FUNCTION
         23.1 Specialized Tissues in Plants
Seed Plant Structure
   Three principal organs
    of seed plants are roots,
    stems, and leaves.
Roots
   Anchor plant in ground
       Help prevent erosion
   Absorb water and
    nutrients and transport
    to rest of plant
   Store food
   Hold plant upright.
Stems
   Support system for the
    plant body
   Transport system that
    carries nutrients
   Defensive system to
    protect against
    predators and disease
   Produces leaves and
    flowers.
Leaves
   Main photosynthetic
    organs
   Regulates water by
    controlling air exchange.
     Plant Tissue Systems
   Three main tissue systems:
     Dermal

     Vascular

     Ground.
Dermal Tissue
   Protective outer covering of a plant
   Epidermis
     Single   layer of cells that makes up the dermal tissue
   May have tiny hair like projections on leaves and
    roots.
     Vascular Tissue
   Supports the plant body
   Transports water and
    nutrients
     Xylem
     Phloem
     Consist of long, slender cells
      that connect almost like
      sections of pipe.
     Xylem
   Tracheids
     Xylem  cells
     Leave cell walls made of
      lignin when they die
     Openings allow water
      movement from cell to
      cell.
      Xylem
   Vessel elements
     Wider   than tracheids
      and are arranged end
     After cell dies, cell walls
      allow water to move
      freely.
        Phloem
   Alive at maturity
   Transports sugar throughout plant
   Sieve tube elements
     Arranged end to end with ends having
      many small holes
     Lose nuclei and organelles as they
      mature
     Kept alive by companion cells.
     Phloem
   Companion cells
     Supports   sieve tube element.
Ground Tissue
   Produces and stores sugars
   Contributes to physical support of plant
   Neither dermal nor vascular
   Three types of ground tissue:
     Parenchyma

     Collenchyma

     Sclerenchyma.
Parenchyma
   Main type of ground tissue
   Have thin cell walls
   Contain many chloroplasts in leaves.
Collenchyma
   Strong, flexible cell walls that help support plant
    organs
   Middle cell wall thickness.
Sclerenchyma
   Extremely thick, rigid cell walls
   Makes ground tissue such as seed coats tough and
    strong.
Meristems
   Regions of unspecialized cells in which mitosis
    produces new cells
   Found in tips of stems and roots.
     Apical Meristems
   Meristem at tip of a stem
    or root
   Cells divide rapidly
   Increases plants length.
Floral Meristems
   Produces flowers specialized cells
   Develop from apical meristem.

				
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