Plants

1
Plants

• Magnet Chapter 24, only parts of 25-28 (Mader
  text)
• Honors Ch 21 and 23?

2
What is a plant?

• Multicellular, autotrophic, eukaryotes
• Plants are adapted for terrestrial life
• Waxy cuticle
• Stomata guard cells
• Root systems shoot systems
• Vascular tissue (xylem phloem)
• Eventually, the advent of the seed!

3
Alga vs. Plant
4
Leaf structure
5
Alternation of Generations

• Plant life cycle

6
Four Main Groups of Land Plants

• Bryophytes
• nonvascular plants
• Pteridophytes
• seedless vascular plants
• Gymnosperms
• vascular plants with naked seeds (no
  flowers)
• Angiosperms
• vascular flowering plants

7
Plants can reproduce with spores and seeds

• Spore and seeds both grow into adult plants
• Seeds are the result of fertilization, and are
  therefore diploid
• Spores are haploid cells that can grow up into
  haploid adults, without participating in
  fertilization

8
Plants Exhibit an Alternation of Generations
9
Bryophytes

• The nonvascular plants
• Ex mosses
• Have flagellated sperm which must swim in order
  to reach the egg
• The dominant generation of the mosses is the
  gametophyte the sporophyte cannot survive
  independently

10
Pteridophytes

• The seedless vascular plant
• Have true roots with vascular tissue fronds
• Sporophyte is the dominant generation
• In order to complete their life cycle, they must
  be in a moist environment, since swimming sperm
  must swim through water to reach the egg
• Ex-Ferns

11
Gymnosperms

• Seeds do not develop within ovaries, but on the
  surfaces of specialized leaves
• Produce seeds, but no flowers or fruits
• Huge advantage pollen!
• Pollen is the male gametophyte (only 2
  cells), and therefore produces the male gamete
  the sperm
• No longer are the sperm restricted to
  aquatic environments to swim to the egg!
• Evergreens, conifers

12
Angiosperms

• Flowering plants
• Parts of the flower- KNOW!
• Fruit a mature ovary function seed dispersal
• Male gametophyte is contained within pollen
  grains
• Ovules within the ovary contain the female
  gametophyte, which produces the female gamete,
  the egg
• Pollination vs. fertilization

13
Life Cycle of an Angiosperm
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Two Groups of Angiosperms

• Although all angiosperms have a number of
  features in common, two plants groups, the
  monocots and dicots, differ in many anatomical
  details.

15
Comparison of monocots and dicots
16
Plant growth

• Annuals
• Perennials
• Roots

17
From flower to fruit to seed
18
Plant Responses

• Plant hormones help coordinate growth,
  development, and responses to stimuli
• Hormones
• Are chemical signals that coordinate the
  different parts of an organism. Made in one
  place and transported to another

19
The Discovery of Plant Hormones

• Any growth response
• That results in curvatures of whole plant organs
  toward or away from a stimulus is called a
  tropism.
• Is often caused by hormones (ex- auxins,
  gibberlins (sp), ethylene, cytokinins.EOCT only)
• If plant grows toward stimulus- positive tropism
  (away from stimulus is negative)
• Examples of tropisms-1- phototropism (growth
  toward light source 2- gravitropism (positive
  downward growth of root negative- upward growth
  of stem away from gravity 3- Thigmotropism-
  Mechanical- growth toward point of contact (like
  a vine around fence or tree)

20
Additional info

• Complete flower vs. incomplete
• Perfect vs. Imperfect flower
• A flower can be perfect, but incomplete. How?
• Growth rings in stems
• How can you tell if it was a rainy season vs a
  drought?
• Tubers and bulbs are underground stems for food
  storage Strawberries are runners (horizontal to
  ground). Form roots when touch ground
• FRUIT- reproductive (anything with seeds)
  VEGETABLE- no reproductive parts (no seeds)