Table of Contents

1
CHAPTER 34The Plant Body
2
Chapter 34 The Plant Body

• Vegetative Organs of the Flowering Plant Body
• Plant Cells
• Plant Tissues and Tissue Systems
• Forming the Plant Body
• Leaf Anatomy Supports Photosynthesis

3
Vegetative Organs of the Flowering Plant Body

• Monocots typically have a single cotyledon,
  narrow leaves with parallel veins, flower parts
  in threes or multiples of three, and stems with
  scattered vascular bundles.
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4
Vegetative Organs of the Flowering Plant Body

• Eudicots typically have two cotyledons, broad
  leaves with netlike veins, flower parts in fours
  or fives, and vascular bundles in a ring.
• Flowering plants that are neither monocots nor
  eudicots are generally similar in structure to
  eudicots.
• Review Figure 34.1
• 4

5
Figure 34.1
figure 34-01.jpg

• Figure 34.1

6
Vegetative Organs of the Flowering Plant Body

• The vegetative organs of flowering plants are
• roots, which form a root system,
• stems and
• leaves, which form a shoot system.
• Review Figure 34.2
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7
Figure 34.2
figure 34-02.jpg

• Figure 34.2

8
Vegetative Organs of the Flowering Plant Body

• Roots anchor the plant and take up water and
  minerals.
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Vegetative Organs of the Flowering Plant Body

• Stems bear leaves and buds.
• Lateral buds form branches.
• Apical buds produce cells that contribute to stem
  elongation.
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Vegetative Organs of the Flowering Plant Body

• Leaves are responsible for most photosynthesis
• their flat blades, oriented perpendicular to the
  suns rays, are well adapted.
• Review Figure 34.5
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Figure 34.5
figure 34-05.jpg

• Figure 34.5

12
Plant Cells

• Plant cell walls have a structure that often
  corresponds to special functions of the cell.
• Walls of individual cells are separated by a
  middle lamella common to two neighboring cells
  each cell has its own primary wall.
• Review Figure 34.6
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13
Figure 34.6
figure 34-06.jpg

• Figure 34.6

14
Plant Cells

• Some cells produce a thick secondary wall.
• Adjacent cells are connected by plasmodesmata
  extending through both cell walls.
• Review Figures 34.7, 34.8
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Figure 34.7
figure 34-07.jpg

• Figure 34.7

16
Figure 34.8
figure 34-08.jpg

• Figure 34.8

17
Plant Cells

• Parenchyma cells have thin walls.
• Many store starch or lipids
• Some others carry out photosynthesis.
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18
Plant Cells

• Collenchyma cells provide flexible support.
• 18

19
Plant Cells

• Sclerenchyma cells provide strength and function
  when dead.
• 19

20
Plant Cells

• Tracheids and vessel elements are xylem cells
  that conduct water and minerals after the cells
  die.
• Review Figures 34.10
• 20

21
Figure 34.10
figure 34-10.jpg

• Figure 34.10

22
Plant Cells

• Sieve tube members are conducting cells of the
  phloem.
• Their activities are often controlled by
  companion cells.
• Review Figure 34.11
• 22

23
Figure 34.11
figure 34-11.jpg

• Figure 34.11

24
Plant Tissues and Tissue Systems

• The vascular tissue system conducts water,
  minerals, and the products of photosynthesis.
• The dermal tissue system protects the body
  surface.
• The ground tissue system produces and stores food
  materials and performs other functions.
• Review Figure 34.12
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Figure 34.12
figure 34-12.jpg

• Figure 34.12

26
Forming the Plant Body

• The apicalbasal pattern and the radial pattern
  are parts of the plant body plan
• They arise through orderly development.
• Review Figure 34.13
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Figure 34.13
figure 34-13.jpg

• Figure 34.13

28
Forming the Plant Body

• Plant development differs from animals.
• The plant body is modular, and the growth of
  stems and roots is indeterminate.
• Leaves, flowers, and fruits show determinate
  growth.
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29
Forming the Plant Body

• Meristems are localized regions of cell division.
• A hierarchy of meristems generates the plant
  body.
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30
Forming the Plant Body

• Apical meristems at the tips of stems and roots
  produce the primary growth of those organs.
• Review Figure 34.14
• 30

31
Figure 34.14
figure 34-14.jpg

• Figure 34.14

32
Forming the Plant Body

• Shoot apical and root apical meristems give rise
  to primary meristems
• protoderm
• ground
• procambium
• Review Figure 34.15
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Figure 34.15
figure 34-15.jpg

• Figure 34.15

34
Forming the Plant Body

• In some plants, the products of primary growth
  constitute the entire plant body. Others show
  secondary growth.
• Two lateral meristems, the vascular cambium and
  cork cambium, are responsible for secondary
  growth.
• Review Figure 34.14
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35
Forming the Plant Body

• The young root has an apical meristem that gives
  rise to the root cap and three primary meristems,
  which produce the three tissue systems.
• protoderm produces the dermal tissue system
• ground meristem produces the ground tissue system
• procambium produces the vascular tissue system.
• Review Figure 34.15
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36
Forming the Plant Body

• Root tips have three overlapping zones
• the zones of cell division,
• cell elongation, and
• cell differentiation.
• Review Figure 34.15
• 36

37
Forming the Plant Body

• The dermal tissue system consists of the
  epidermis, part of which forms root hairs
  responsible for absorbing water and minerals.
• Review Figure 34.16
• 37

38
Figure 34.16
figure 34-16.jpg

• Figure 34.16

39
Forming the Plant Body

• The ground tissue system of a young root is the
  cortex, whose innermost cell layer, the
  endodermis, controls access to the stele.
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Forming the Plant Body

• The stele, consisting of pericycle, xylem, and
  phloem, is the roots vascular tissue system.
• Lateral roots arise in the pericycle.
• Monocot roots have a central pith region.
• Review Figure 34.17
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41
Figure 34.17
figure 34-17.jpg

• Figure 34.17

42
Forming the Plant Body

• The shoot apical meristem gives rise to three
  primary meristems, with roles similar to
  counterparts in the root.
• Leaf primordia on the sides of the apical
  meristem develop into leaves.
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43
Forming the Plant Body

• Vascular tissue in young stems is divided into
  vascular bundles, each containing xylem and
  phloem.
• Pith occupies the center of the monocot stem.
• Cortex lies to the outside of vascular bundles in
  monocot, and pith rays lie between them.
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44
Forming the Plant Body

• Many eudicot stems and roots show secondary
  growth, in which vascular and cork cambia give
  rise to secondary xylem and phloem.
• As secondary growth continues, wood and bark are
  produced.
• Review Figure 34.19
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Figure 34.19 Part 1
figure 34-19a.jpg

• Figure 34.19 Part 1

46
Figure 34.19 Part 2
figure 34-19b.jpg

• Figure 34.19 Part 2

47
Forming the Plant Body

• The vascular cambium lays down layers of
  secondary xylem and phloem.
• Living cells within these tissues are nourished
  by vascular rays.
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48
Forming the Plant Body

• The periderm consists of cork, cork cambium, and
  phelloderm, all pierced at intervals by lenticels
  that allow gas exchange.
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Leaf Anatomy Supports Photosynthesis

• Mesophyll is the photosynthetic tissue of a leaf.
  
• Veins bring water and minerals to the mesophyll
  and carry products of photosynthesis to other
  parts of the plant body.
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Leaf Anatomy Supports Photosynthesis

• A waxy cuticle prevents water loss from the leaf,
  but is impermeable to carbon dioxide.
• Guard cells control opening of stomata, leaf
  openings that allow CO2 to enter but also water
  to escape.
• Review Figure 34.23
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51
Figure 34.23
figure 34-23.jpg

• Figure 34.23