Chs' 2225:

1
Chs. 22-25

• THE PLANT KINGDOM

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22-1 What is a Plant?

• A multicellular eukaryote
• Photosynthetic (producer, autotroph) use
  chlorophyll a b
• Has cell walls made of cellulose
• Reproduces either sexually (sperm, egg) or
  asexually (spores)
• Most closely related to green algae
• Reproduce by alternation of generations
  gametophyte (N) produces gametes which fuse to
  produce the sporophyte (2N), spore-producing
  plant ?cycle continues
• Some use vegetative (asexual) reproduction

3
ALGAE ?
KINGDOM PLANTAE
BRYOPHYTES
TRACHEOPHYTES

• Nonvascular
• Grow low to ground, in wet places
• No true roots, stems, leaves (rhizoids are
  root-like)
• Mosses, hornworts, liverworts
• Spore-producers

Vascular land plants
Angiosperms (Flowering Plants)
Gymnosperms (Cone-Bearing Plants)
Ferns (primitive spore producing)
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Bryophytes Gametophyte is Visible

• Moss

Liverwort
Hornworts
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Seedless Tracheophytes

• Have vascular tissue (xylem - water, phloem
  nutrients in solution) for materials management
• Sporophyte is dominant through life cycle
• Seedless spore-producing
• Have roots, stems, leaves
• Ferns (Phylum Pterophyta) tropical regions
• Club mosses (Lycophyta) - ground pine
• Horsetails (Arthrophyta) leaves at midribs
  (joints on stem)

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Seed Producing - Tracheophytes

• Reproduce w/o water
• Advanced plants
• Gymnosperms 4 phyla of cone producers, use
  cones with seeds to reproduce, needlelike leaves.
  Ex) ginkgoes, cycads, conifers (22-4)
• Angiosperms flowering plants, divided into
  classes monocot and dicot (22-5). See fig 22-25
  p. 570. Can be woody or herbaceous (green)
  annuals (life cycle one season), biennials
  (two-year life), perennials (more than two years
  woody stems). Some seeds develop in fruits to
  attract animals.

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23-1 Specialized Tissues

• Three tissues in plants
• Dermal outer covering of epidermal cells (flat,
  circular) covered by waxy cuticle and trichosomes
  (fuzz).
• Vascular xylem and phloem
• Ground (between dermal and vascular) parenchyma,
  sclerenchyma, collenchyma.
• Additional tissue at tips of shoots and roots
  (growth) meristematic tissue which undergoes
  mitosis.

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23-2 Roots

• Fibrous (monocot) or taproot (dicot)
• Root cap protects end of root as it grows through
  soil
• Vascular cylinder in center of root
• Functions
• Uptake of nutrients (see 23-8 p. 586)
• Active Transport of dissolved minerals (water
  moved against gradient into cells where ion
  concentration is high)
• Maintain root pressure forcing water through
  vascular tissue of plant.

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23-3 Stems

• Stems 1) produce leaves, flowers
• 2) hold leaves to sunlight
• 3) transport materials
• Monocot stems vascular bundles scattered
• Dicot stems vascular bundles arranged in a ring
• Primary Growth cell divisions at apical
  meristem (ends of branches)
• Secondary Growth stems increase in width

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23-4 Leaves

• Absorb light, carry out photosynthesis in special
  ground tissue pallisade mesophyll, spongy
  mesophyll in center of leaf
• Leaf covered in waxy cuticle to prevent water
  loss
• Stomata (openings) on leaf for gas exchange
  protected by guard cells to open/close stomata.
• Transpiration loss of water through leaf,
  pressures plant to continue to draw water
  (capillary action).
• Simple (one) leaf vs. compound leaf (leaflets)

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24-1 Reproduction in Seed Plants

• Seed plants show alternation of generations
  recognizable part of plant is diploid sporophyte
• Gymnosperm gametophyte inside cones (pollen
  cone makes pollen, seed cone makes egg cells)
• Angiosperm gametophyte inside flowers (stamen
  makes pollen on anthers, ovary holds egg cells)
• Pollination occurs by wind or animals (when
  carried by bee or bird called vector pollination)

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24-2 Seeds and Fruits

• In angiosperms, seeds mature and ovary around it
  thickens to become fruit
• Fruits can be fleshy or dry (lab)
• Seeds are dispersed by wind, water, animals, and
  mechanical means (expulsion) (lab)
• Seeds can be dormant until temperature and
  moisture are right for germination

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25-1, 2 Plant Growth and Response

• Hormones - chemical substances in plants that
  control tissue growth and development, also
  responses like growing toward light
  (phototropism)
• Winter dormancy occurs when growth stops as the
  plant is signaled to turn off photosynthesis in
  leaves, move materials to roots, and leaves fall
  off.