Plants 2

1
Plants 2

• Read 422-464
• Study for Test next class
• NR 4 due in a week(ish)

2
Review

• Gymnosperms
• Mainly conifer trees, naked seeds, thick bark
• Eudicots (Angiosperms)
• Flowering plants, branched veins, 4/5 petals
• Monocots (Angiosperms)
• Flowering plants, parallel veins, 3 petals

3
Defense

• 4 major strategies for defense
• Chemical
• Growth of non-essential structures
• Encourage predation from other species
• Mechanical

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Chemical and Mechanical

• Production of non-essential organic compounds
  that do not aid in growth or reproduction of the
  plant.
• toxins
• Production of structures on leaves and stems
  discourage herbivores through injury or death.
• Thorns, waxy coatings, poison spines, sap

5
Mutualism

• Some plants develop structures to house another
  species that will protect it from predators.

6
Flower structure

• A flower is a reproductive organ in angiosperm
  plants.
• Considered a modified stem
• Arranged in whorls (spiral patterns)
• Whorls from outer to inner
• Sepals, petals, stamen, pistil

7
Perfect flowers?

• A flower is considered perfect if it has both a
  stamen and pistil.
• These flowers are also known as bisexual or
  hermaphroditic.
• If a flower is imperfect it may only contain
  male or female parts.
• If both male and female parts are on the same
  plant (but different flowers)?monoecious
• Male and female flower parts are on different
  plants ?dioecious.

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Flowers are for reproduction

• The main purpose for flowers is to mediate the
  joining of pollen to ovary (sperm to ovule).
• Pollination by insects and flower phenotype are
  adaptations to increase the likelihood of
  fertilization.
• Many times, this coevolution can be seen having
  negative effects when one species or the other
  becomes endangered.

9
Fruit

• A fruit is a ripened ovary and surrounding
  tissues.
• A main way that plants spread seeds.
• In cooking, many culinary vegetables are actually
  fruits
• Squash, pumpkin, cucumber, tomatoes, peas, beans,
  corn, eggplant, chilies, etc
• Nuts are also types of fruit, but are often
  classified as edible seeds (peanuts, pistachios)

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Types of fruit

• 3 types of fruit
• Simple, aggregate, multiple
• Simple Comes from one pistil. (ex avocado)
• Aggregate Comes from a flower with many pistils
  (ex raspberry)
• Multiple multiple flowers that create one
  massive fruit (ex pineapple)
• Seedless fruit
• Caused by either breeding or because fruit is not
  a result of fertilization (plant reproduces via
  asexual means).

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Fruit Anatomy

• Exocarp- tough skin with oil glands and pigments
• Mesocarp- The fleshy portion of the fruiting
  body.
• Endocarp- The portion of the fruit that directly
  surrounds the seed.
• Seed- The immature plant that will begin to grow
  under the right conditions.

12
Plant hormones

• 5 major hormones
• Abscisic acid (ABA) prevents leaf stem growth.
• Auxin influence cell growth, bud formation, root
  initiation
• Cytokinin influence shoot formation
• Ethylene fruit ripening
• Gibberellin seedling growth, flowering, reverses
  ABA