Plant Classification by linzhengnd

VIEWS: 6 PAGES: 47

									Form and Structure of Plants




  Botany: the study of plants
    What is a plant?

   Living organisms which are
    eukaryotic and multicellular
   Have organized tissues
   Have plastids (such as chloroplasts)
   Have cell walls containing cellulose
 One reason the study of botany
 is so important to man is …

Because all the food eaten by man
comes directly or indirectly from
green plants. About 2/3 of the food
we eat comes directly from plants
and 1/3 comes from animals which
eat plants.
Ways Plants are Beneficial:
   Provide most of man's food
   Release O2 needed by man and
    animals
   Plants are raw materials for
    many manufactured goods
   Plants are a source of beauty
    Misconceptions:
 All green things are plants.
 All plants
  are green.
 All plants
  are
 autotrophic.
morphology

the shape or form of an organism
 Anatomy
the bodily
structure of
an organism
(deals with
how cells and
tissues are put
together)
Types of organs in plants

   Roots              Flower
   Stems
              Leaf      Stem
   Leaves
   flowers     Root
   Plant organs are determined by
   their relationships to nodes


     Node:
a region where
a leaf is or was
    attached
Plant organs are determined by
their relationships to nodes
   Roots do not have nodes.
   Stems have nodes.
   Leaves do not have nodes but are
    attached to stems at nodes.
 Roots


Roots are the organs of
the root system.

A root system is all the
roots of a plant.
Functions of Roots

   Anchors
   Absorbs
   Transports
   Stores food
Two Types of Root Systems

   Taproots

   Fibrous roots
Taproots
         commonly found in
          dicots
         penetrates the
          soil with very
          little branching
          often stores food
          (fleshy roots)
Taproots
         has one or a few
          main roots that are
          thicker and longer
          than the other
          roots of the plant
         examples: carrots
          and dandelions
   Fibrous Root System
 commonly found
  in monocots
 have no main
  section but
  branch out into
  the soil in all
  directions
   Fibrous Root System
 Has a cluster of
  roots that are
  approximately
  equal in size
 They branch
  several times
 Example:  grasses
Types of stems


     Herbaceous stems
     Woody stems
Herbaceous stems
                Softer, more flexible
                 type of stem
                Supported by cell
                 walls and turgor
                 pressure
                Woody plants often
                 begin as herbaceous
                 and then become
                 woody as the grow
                 older
Woody stems
                 Hard and not very
                  felxible
                 Capable of
                  supporting a lot of
                  weight
                 Examples: trees
                  and shurbs
Stem Functions
 manufacture,
 support, and display
 leaves
 conduct materials
External Structures of Leaves
                   Blade: the flat portion
                   of a leaf
                   Petiole: the stalk of a
                   leaf; attaches leaf to stem
                   Margin: the edge of a
                   leaf’s blade
          Margin   Veins: the pipelines that
                   carry food & water
                   Node: place on stem
                   where leaves are attached
   External Structures of Leaves




Stipule: a small leaflike or scalelike structure on
a plant that helps to cover a leaf while it is
devleoping
        Leaf Venation




Two basic patterns of leaf venation:
       • Parallel Venation
       • Netted Venation
Parallel Venation

             A series of veins which
             originate at the stem and
             proceeds to the tip of the
             leaf

             Occurs in monocots – corn,
             grass, irises, orchids
 Netted Venation

             Palmate: two or more main veins
             coming from a single point
             Examples: maple, ivy, geraniums

Pinnate: if the veins branch off one
large central vein called a midrib
Examples: oaks, apple trees,
African violets
Classification of Leaves

       Simple leaves
       Compound leaves
Simple or Compound?




Simple Leaves: one blade on each petiole
Simple or Compound?




Compound: more than one blade on each petiole
     Each small blade on a compound leaf is
     referred to as a leaflet
Sessile Leaves



                 Sessile leaves lack
                 petioles
Sessile Leaves




Grasses and certain other monocots have
sessile leaves that attach to the stem by way of
a sheath that seems to wrap around the stem
Leaf Mosaic




Alternate   Opposite   Whored

 Leaf mosaic: the arrangement
      of leaves on a stem
Leaf Mosaic
Alternate Mosaic: leaves alternate from
opposite sides of the stem (one petiole per
node)
Leaf Mosaic
Opposite Mosaic: two leaves grow from the
same point on the stem (two petioles per
node)
Leaf Mosaic




Whorled Mosaic: three or more leaves
grow from a single point on a stem (3 or
more petioles per node)
Leaf Mosaic
   Leaf Shapes




Linear    Lobed     Cordate   Deltoid


         Circular
Linear Leaf Shape




        long and narrow
Lobed
Leaf Shape
Cordate Leaf Shape




      kidney or heart-shaped
Deltoid Leaf Shape




          deltoid-shaped
Circular Leaf Shape
   Leaf Margins




Entire   Serrate   Undulate   Dentate
Entire Leaf Margin




   smooth margin with no teeth
Serrate Leaf Margin




        toothed margins
Undulate Leaf Margin




         wavy margins
Dentate Leaf Margin




        teeth point out

								
To top