plant_parts by hedongchenchen

VIEWS: 22 PAGES: 43

									 Plant Parts and their
       Functions

13.00 Describe principles of plant
science as related to horticulture
14.00 Compare the anatomical parts
and distinguishing characteristics of
horticultural plants
         Plant Sciences
• Biology-the branch of science that
  deals with both plant and animal
  organisms and life processes
  – Zoology-the part of biology that deals
    with animals
  – Botany the part of biology that deals
    with plants
         Plant Sciences
• Applied plant sciences are based
  on the purposes for which the
  plants are grown
  – Agronomy
  – Forestry
  – Horticulture
           Agronomy
The science and practice of growing
 field crops such as cotton, wheat,
 tobacco, corn and soybeans.
            Forestry
The science and practice of growing,
 managing and harvesting trees for
 building materials and other
 products.
          Horticulture
The science and practice of growing,
 processing and marketing fruits,
 vegetables, and ornamental plants
    Life Cycles of Plants
• Annual-a plant that completes its
  life cycle in one year
• Biennial-a plant that completes its
  life cycle in two years – 1st –
  vegetative, 2nd - reproductive
• Perennial-a plant that lives more
  than two years
        Leaf Retention
• Deciduous-loses leaves during the
  dormant season
• Evergreen-keeps leaves and
  remains green year-round
        Plant Hormones
• Several types of hormones are
  used to help plants work more
  efficiently.
  – Inhibitors
  – cytokinins
  – gibberellins
  – auxins
           Inhibitors
• Inhibitors hasten fruit ripening,
  retain seed germination and stem
  elongation.
          Cytokinins
• Hormones that work with auxins to
  stimulate cell division.
          Gibberellias
• Hormones that stimulate cell
  elongation, premature flowering,
  and breaking of dormancy.
             Auxins
• Hormones that speed plant growth
  by stimulating cell enlargement
• Typically in rooting hormone
      Moisture in Plants
• Turgid-plant is swollen or filled
  with moisture
• Wilted-plant is limp because it
  does not have enough moisture
            Plant Parts
• Leaves
• Stems
• Roots
• Flowers
       Leaves-External
• Petiole-leaf stalk or part that
  connects the leaf to the stem
• Blade-the large, flat part of the
  leaf
• Midrib-the large center vein
• Veins-the structural framework of
  the leaf
• Margin-the edge of the leaf
Leaves-External
       Leaves-Internal
• Upper and lower epidermis-skin of
  the leaf that prevents the loss of
  too much moisture
• Stomates-small openings under
  the leaf for breathing or
  transpiration
• Guard Cells-open and close
  stomates
        Leaves-Internal
• Chloroplasts-small green particles
  that contain chlorophyll
  – gives leaves their green color
  – necessary for photosynthesis
Leaves-Internal
Leaves-Internal
        Stems-External
• Lenticels-breathing pores
• Bud scale scars-show where
  terminal buds have been located
• Leaf Scars-show where leaves
  were attached
• Terminal bud-bud on the end of a
  stem
• Axillary or lateral bud-bud on side
  of stem
        Stems-Internal
• Xylem-tissue that transports water
  and nutrients up from the roots to
  stems and leaves
• Phloem-tissue that transports food
  down from leaves to roots
         Stems-Internal



Phloem                Phloem




             Xylem
       Stems-Internal
• Cambium-thin, green, actively
  growing tissue located between
  bark and wood and produces all
  new stem cells
• Bark-old inactive phloem
• Heartwood-old inactive xylem
• Sapwood-new active xylem
          Stems-Internal
  Bark

                             Cambium
Sapwood




                           Heartwood
        Stems-Internal
• Monocota-plant stems have
  vascular bundles that contain both
  xylem and phloem in each bundle
  – examples: corn, grasses

• Dicata-plant stems have the
  phloem layer and xylem layer
  separated by cambium
  – example: trees
   Stems-Internal




Monocot        Dicot
        Roots-External
• Root cap-indicates growth of new
  cells
• Root hairs-absorb moisture
  (water) and minerals

                          Root
                          images
                          from a rice
                          plant
        Roots-Internal
• Much like stems in that they have
  a phloem, cambium, and xylem
  layer
• Phloem-the outer layer that carries
  food down the root
• Xylem-the inner layer that carries
  water and minerals up to the stem
        Layers of Roots
• Fibrous-many branched shallow
  roots
  – are easier to transplant

• Tap-long root with few branched
  ones
  – more difficult to transplant
             Flowers
• Sepals-Green parts that cover and
  protect flower bud before it opens
• Petals-are really leaves that are
  modified to attract insects for
  flower pollination, the pretty part
  that we call flowers
• Stamen-male part of the flower
• Pistil-female part of the flower
Flowers
    Parts of the Stamen
• Filament-short stalk that
  holds up the anther
• Anther-a sac-like structure
  that contains pollen, the
  male sex cells
       Parts of the Pistil
• Ovules-the eggs or female sex
  cells that become seeds if fertilized
• Ovary-if fertilized becomes a fruit
  or seed coat
• Style-holds up the stigma and
  connects it to the ovary
• Stigma-sticky part on top of style
  where insects leave pollen
        Parts of the Pistil
                          Stigma




Style




   Ovary
 Complete-vs-Incomplete
• Complete flowers have all four basic
  parts. (Sepals, petals, stamen, and
  pistil)
• Incomplete flowers are missing one of
  the four basic parts.
• Perfect flowers – Has both male and
  female parts
• Imperfect flowers – Has only male or
  only female parts.
  What are the
functions of these
   plant parts?
     Functions of Leaves
• Photosynthesis-manufactures food
  in green plants which is the
  beginning of the food chain for all
  living things
• Photosynthesis is the process by
  which carbon dioxide and water in
  the presence of light are converted
  to sugar and oxygen
      Chemical Formula
• CO2 + H2O  C6H12O6 + 6O2

Carbon water      glucose    oxygen
Dioxide
Must be in the Presence of
 SUNLIGHT!
     Functions of Stems
• Translocation-moves water and
  minerals from roots up to the
  leaves and move food from the
  leaves down to the roots
• Supports branches, leaves,
  flowers, fruits and seeds
     Functions of Roots
• Absorption-take water and
  nutrients from the soil and conduct
  them to the stem
• Anchor the plant and hold it
  upright
• Store food for plant use
• Asexual reproduction in some
  plants
    Functions of Flowers
• Produce seeds used for sexual
  reproduction
• Attract insects for pollination
  (Pollination is the transfer of pollen
  from anther to stigma.)
• Produce fruit to protect, nourish
  and carry seeds

								
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