Chapter 31: Plant Structure, Reproduction, and Development

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Lecture 20

• Chapter 31 Plant Structure, Reproduction, and
  Development

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Learning Objectives (p. 1 of 2)

• Recall
• The species of General Sherman
• Define
• Runner
• Stems, runners, tubers
• Tendril
• Stomata, guard cells

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Learning Objectives (p. 2 of 2)

• Contrast
• Monocots vs. Dicots (identify by vascular
  pattern)
• Xylem vs. phloem
• Roots vs. shoots
• Label
• The various structures of a flower (given an
  unlabelled figure)

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Worlds Biggest Plant

• The General Sherman Tree
• Species is Sequoiadendron gigantea
• Central California
• 2500 years old!!!
• National Park Service site
• US Geological Survey site

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Angiosperms

• These are flowering plants
• Two basic types
• Monocots
• Dicots

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Monocots

• Have one seed leaf
• Root network very fibrous
• Leaves have parallel veins
• Examples orchids, bamboos, palms, grasses
  (including rice, other grains)

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Dicots

• Have two seed leaves
• One main taproot plus root hairs
• Leaves have multiply branched veins
• Ex trees, shrubs, carrots

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Monocots vs. Dicots
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Question

• Where would we classify pine trees?

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Answer

• Trick question they arent angiosperms
• Theyre gymnosperms (no flowers!)
• Sequioadendron giganteum is a gymnosperm

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Roots and Shoots

• Be able to contrast the functions of each

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Root System

• Have root hairs to increase surface area
• Helps with water, nutrient absorption
• Roots also store food
• Anchoring for plant

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Shoot System (Leaves)

• Generally flat, some are modified into
• Tendrils
• Spines

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Shoot System (Stems)

• Nodes where leaves attach
• Internode areas in between
• Horizontal stem rhizome
• Potato (tuber)
• Strawberry runner

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Primary vs. Secondary Growth

• Primary growth makes plant taller
• Secondary growth makes plant fatter

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Primary Growth

• Occurs at meristems (groups of unspecialized,
  growing cells)
• Will give rise to specialized tissues for
• Food transport
• Water transport

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Vascular Cambium The Key to Secondary Growth

• Vascular cambium (green, below) gives rise to
• Xylem
• Phloem
• Cork cambium
• Cork

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A Tree Gets Fatter

• Top baby tree
• Middle 1 year old tree
• Bottom 2 year old tree

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What is Wood?

• New xylem (sapwood)
• Contains water-conducting cells
• Carries water and nutrients toward the leaves
• Old, dead xylem (heartwood)
• Accounts for most of tree trunks diameter
• Tree builds layer after layer of xylem

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Cork

• Produced on outside of tree (by cork cambium
  cells)
• Unlike xylem, does not accumulate
• Sloughed off continously

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Xylem

• Carries water and nutrients
• Has water-Conducting Cells
• Die at maturity
• Leave hollow cell wall
• Like a pipe
• Two types
• Tracheids
• Vessel Elements

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Vascular Pattern Monocots vs. Dicots
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Phloem

• Contains food conducting cells
• Newest layer transports sugars to tissues, roots
• Oldest layers die, contribute to bark (along with
  cork)

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Vascular Cambium

• Cells divide for the life of the tree
• Gives rise to xylem and phloem

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What is Bark?

• Everything external to vascular cambium
• Phloem
• Cork cambium
• Cork

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Sterile Parts of a Flower

• Sepals usually green, look like leaves
• Protect flower bud before it opens
• Petals Usually brightly colored

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Additional Sterile Vocabulary

• Calyx all the sepals together
• Corolla all the petals together
• Perianth calyx and corolla

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Fertile Parts of a Flower

• Stamens the male parts of the flower
• Anthers make pollen grains
• Carpel the female parts of the flower
• Stigma tip of the carpel, receives pollen
• Ovary the base of the carpel housing the
• Ovule contains developing egg placenta

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Additional Fertile Vocabulary

• Androecium all the stamens
• Greek for house of man
• Gynoecium all the carpels
• Greek for house of woman

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Seventh Inning Stretch