Chapter 2 – Atoms, Molecules, and Life

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Why Protect A Dying Leaf?
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Chapter 42 Plant Anatomy Nutrient Transport
7th Edition in Audesirk, Audesirk, and
Byers Chapter 24 Plant Anatomy Nutrient
Transport

• 42.1 - How Are Plant Bodies Organized How Do
  They Grow? p. 860
• 42.2 - The Tissues and Cell Types of Plants? p.
  862
• 42.3 - The Structures, Functions of Leaves,
  Roots, Stems? p. 865
• 42.4 - How Do Plants Acquire Mineral Nutrients?
  p. 873
• 42.5 - How Do Plants Move Water Upward from Roots
  to Leaves? p. 876

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Plant Anatomy Systems and Tissues

• How Are Plant Bodies Organized, and How Do They
  Grow?
• Flowering Plants Consist of a Root System and a
  Shoot System.
• As Plants Grow, Meristem Cells Give Rise to
  Differentiated Cells.

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The Art and Science of Living
Survive (live)
Support the body Obtain water
nutrients Transport water nutrients Obtain
energy Grow and Develop Exchange gases ?
Protection from Herbivory
Reproduce
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Angiosperms (Monocots and Dicots)

• Flowering plants (called Angiosperms) are divided
  into two groups (monocots and dicots) based on
  the structure of their flowers, leaves, vascular
  tissue, roots, and seeds.

• Largest phylum of living plants.
• 250,000 species.
• Seeds enclosed by fruits.

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Theophrastus (370 286 B.C.)
Father of Botany. Author of the oldest treatise
on pure botany, Historia Plantarum, in which he
described about 480 kinds of plants. Family,
Theophrastaceae
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Carl Linnaeus (1707-1778)
Swedish naturalist Carolus Linnaeus was the
first to formalize the use of higher taxa in his
book Systema Naturae (1735), establishing the
standard hierarchy taxonomy still in use today.
In addition, Linnaeus devised logical rules to
classify species that continued to be used by
scientists for over 200 years.
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Plant Anatomy Roots Shoots

• Root and shoot systems are made up of basic plant
  organs roots, leaves, stems, flowers.

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Root System Functions

• Anchor plant.
• Absorb water and minerals.
• Store sugar as starch.
• Transport materials
• Produce some hormones.
• Interact with soil microbes.

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Shoot System Functions

• Photosynthesis (primarily in leaves)
• Transport of materials (water, minerals, sugars,
  and hormones among leaves, flowers, fruits, and
  roots)
• Reproduction
• Hormone synthesis

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Structure is used in classification
Angiosperms (Monocots and Dicots)

• Monocots have one cotyledon (seed leaf)
• e.g. grasses, lilies, palms, orchids
• Dicots have two cotyledons (seed leaves)
• e.g. deciduous trees (drop leaves
• in winter), bushes, many garden flowers

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Flowers
Monocots flower parts in 3s
Dicots flower parts in 4s, 5s, 6s
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Leaves
Monocots parallel veins in leaves
Dicots network of veins in the leaves
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Stems
Monocots small vascular bundles scattered
throughout the stem.
Dicots large vascular bundles arranged in a ring
around the stem.
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Roots
Monocots fibrous root system with no main tap
root.
Dicots Main tap root, with smaller side roots
branching off.
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Seeds
Monocots single cotyledon endosperm and
cotyledon are separate.
Dicots two cotyledons endosperm is contained in
the cotyledon.
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Plant Tissues
? Dermal Tissue - Epidermis -
Periderm ? Ground Tissue - Parenchyma -
Collenchyma - Sclerenchyma ? Vascular
Tissue - Xylem - Phloem
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Dermal Tissue Epidermis

• Covers flowers, seeds, fruit.
• Secretes a waxy substance called cuticle
  (cuticular membrane - hydrophobic) as
  waterproofing.
• May produce special structures such as hairs
  (root hairs). Why?

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Dermal Tissue Periderm

• Replaces epidermis on roots and stems of woody
  plants with age.
• Composed mainly of thick, waterproof cork cells.
• Protects stems and roots.
• Anchor system (doesnt absorb water minerals).

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Plant Tissues
Parenchyma Collenchyma Sclerenchyma
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Ground Tissue Parenchyma

• Non-dermal, non-vascular.
• Thin-walled cells
• Alive at maturity
• Many functions, including photosynthesis, starch
  storage, hormone production.

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Ground Tissue Collenchyma

• Flexible support tissue.
• Elongated cells with irregular shapes and
  unevenly thickened walls.
• Living at maturity.

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Ground Tissue Sclerenchyma

• Support tissue.
• Elongated cells with thick cell walls.
• Dead at maturity.
• Forms long fibers, or smaller sclerids (such as
  stone cells in pears).

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Vascular Tissue Xylem

• Sclerenchyma fibers
• Long, tube-like cells, joined end-to-end, that
  transport water and minerals from soil to leaves.
• Two types of cells tracheids (in conifers) and
  vessel elements (in flowering plants).

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Vascular Tissue Phloem

• Tissue that transports dissolved sugars (sap) in
  a plant.
• Two types of cells
• Sieve tubes (alive but no nucleus)
• Companion cells

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In Review. . . .
Monocots
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In Review. . . .
Dicots
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Why Protect A Dying Leaf?