Plant Form and Function

1
Plant Form and Function

• Molecular biology is revolutionizing the study of
  plants.
• Plant biology reflects the major themes in the
  study of life.
• Lecture 1
• Plant Structure and Growth The Plant Body
• Lecture 2
• Transport in Plants
• Plant Nutrition
• Lecture 3
• Plant Reproduction and Development
• Control Systems in Plants

2
Plant Structure and Growth

• A rather new large vocabulary is needed to name
  the specialized cells of plant anatomy and
  morphology. Focus your attention on
• How the roots, stems, and leaves of a plant are
  specialized to function in absorption, support,
  transport, protection, and photosynthesis.
• Plant exhibit indeterminate growth.
• Apical meristems at the tips of roots and shoots
  create primary growth the primary meristems
  produce dermal, ground, and vascular tissues.
• The lateral meristems, vascular cambium and cork
  cambium, create secondary growth that adds girth
  to stems and roots.

3
The Angiosperm Body

• A plants root and shoot systems are evolutionary
  adaptations to living on land.
• Structural adaptations of protoplasts and walls
  equip plant cells for their specialized
  functions.
• The cells of a plant are organized into dermal,
  vascular, and ground tissue systems.

4
The Angiosperm Body

• Two classes including Monocot and Dicots
• Figure 35.3, know all the differences below

5
Monocot vs Dicot Development
http//images.encarta.msn.com/xrefmedia/aencmed/ta
rgets/illus/ilt/T630888A.gif
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The Angiosperm Body

• In order to inhabit soil and air, plants
  developed a root and a shoot system.
• Roots absorb water and nutrients while shoots
  obtain CO2 and light to make glucose.
• Vascular tissue transports these materials, xylem
  (roots up) and phloem (leaves down).
• Figure 35.4

shoot
root
http//extension.oregonstate.edu/mg/botany/images/
fig24.gif
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The Angiosperm Body

• Review Figure 35.1
• Review Figure 35.4

8
Angiosperm body The Cells of a Plant

• Dermal Tissue (Epidermis with cuticle)
• Vascular Tissue (xylem and phloem)
• Ground Tissue
• Figure 35.12

9
www.uic.edu/.../bios100/labs/plantanatomy.htm
10
Plant Growth and Development
Impatiens

• Plants are called annuals if their life span
  occurs over one year. (Have to re-plant every
  year.)
• Biennials have a life span that occurs over two
  years.
• Perennials have lives that occur over a number of
  years.

http//www.parkviewgardens.com/images/AztecCherryR
ed.jpg
Cabbage
http//www.laughingstockfarm.com/images/July2003/
Cabbage20Savoy20Field20220Web.JPG
Clematis
biology.clc.uc.edu/.../ranunculaceae/clematis/
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Plant Growth and Development

• Meristems are embryonic growths that exist in the
  plants growing regions they generate cells for
  new organs throughout the lifetime of the plant.

Notice dicotyledons
12
Plant Growth and Development Primary Development

• Apical meristems are located at the tips of roots
  and in buds of shoots, and these are sites of
  cell division.
• Primary growth occurs when the plant grows at the
  apical meristem.
• Secondary growth is when the shoots and roots of
  a plant thicken this is the product of lateral
  meristems and occurs in woody plants.

Shoot
http//www.mie.utoronto.ca/labs/lcdlab/biopic/fig/
34.14.jpg
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Plant Growth and Development Primary Development
http//www.ulg.ac.be/cedevit/image/Def/meristeme_e
.jpg
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Plant Growth and Development Primary Development
http//www.csdl.tamu.edu/FLORA/Wilson/tfp/veg/root
s.gif
15
Plant Growth and Development Roots

• The root cap covers the tip of the root in the
  plant, and contains three types of cells in
  various stages of growth, in the following zones
• Zone of Cell Division
• Zone of Elongation
• Zone of Maturation

concise.britannica.com/ebc/art-66109
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Roots Zone of Cell Division

• Mitosis or Zone of cell divisionIncludes apical
  and primary meristems where cells divide rapidly
  (mitosis), and a quiescent center where cells
  divide more slowly.
• Above apical meristem, cells form three
  concentric cylinders of cells that continue to
  divide
• Protoderm
• Procambrium
• Ground meristem

(Review figure 35.15)
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Roots Zones of Elongation Maturation

• Zone of Elongation - above zone of cell division,
  cells elongate.
• Zone of Maturation - the three systems in primary
  growth complete differentiation and become
  functionally mature

18
Plant Growth and Development Roots

• In roots, the procambrium gives rise to the
  stele, a central cylinder of vascular tissue in
  which xylem and phloem both develop.
• The outermost layer of the stele is the
  pericycle.
• The endodermis is a ring, one cell thick, that
  separates the cortex from the stele.

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Plant Growth and Development Roots
www.ju.edu.jo/ecourse/Basics20of20Fruit20T...
20
Plant Growth and Development Roots
http//mansfield.osu.edu/sabedon/campbl30_files/i
mage019.jpg
21
Plant Growth and Development Shoots
At a shoot, the apical meristem is a dome of
dividing cells (mitosis) at the tip of a terminal
bud.
cyberlab.lh1.ku.ac.th/.../fi15/web/chapter3.html
22
Plant Growth and Development Shoots

• The apical meristem gives rise to protoderm,
  procambrium, and ground meristem, which also
  develop into vascular tissues.

23
Plant Growth and Development Leaves

• The epidermis of the underside of the leaf is
  interrupted by stomata, which are small pores
  flanked by guard cells, which open and close the
  stomata.
• The ground tissue is sandwiched between the upper
  and lower epidermis, in the mesophyll. It is
  made up of parenchyma cells, the sites of
  photosynthesis.

www.emc.maricopa.edu
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Growth Videos

• http//video.google.com/videoplay?docid-322977792
  6580585019qplantgrowthhlen
• http//video.google.com/videoplay?docid9100970596
  309336931qplantgrowthhlen
• http//video.google.com/videoplay?docid7556666328
  340725018qtreegrowthhlen

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Plant Growth and Development Secondary Growth
Lateral Meristems

• Two take part in plant growth
• Vascular Cambium which produces secondary xylem
  (woody)

http//www.mie.utoronto.ca/labs/lcdlab/biopic/fig/
34.19a.jpg
26
Plant Growth and Development Secondary Growth
Lateral Meristems

• 2. Cork Cambium
• which produces a tough covering that replaces
  the epidermis

http//www.uic.edu/classes/bios/bios100/lectf03am/
treetrunk.jpg
27
Plant Growth and Development Secondary Growth
Lateral Meristems

• Early in secondary growth, the epidermis dries up
  and is replaced by cork cambium cork cambium
  produces cork cells, and together the cork plus
  cork cambium make up the periderm.

www.ucmp.berkeley.edu
Three cross-sections of older basswood twigs.
Note the annual growth rings and the complete
vascular cylinder producing secondary xylem to
the inside and secondary phloem to the outside.
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Plant Growth and Development Secondary Growth
Lateral Meristems

• Openings or splits in the cork cambium, called
  lenticels, enable the cells within the trunk to
  exchange gases with the outside, and continue
  cell respiration.
• Bark is all the tissues in the vascular cambium.

http//cache.eb.com/eb/image?id65177
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Growth in plants occurs by elongation and
expansion, as well as by cell division.
www.biology.arizona.edu