Exam 2 - Notes

Chapter 35

Introduction to Plants

Kingdom Plantae

From seed to seed

The life of a flowering plant

Alternation of Generations

Gametophyte (haploid)
Sporophyte (diploid)

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The plant embryo

The plant body

Composed of three organ types

Shoot system

Root system

Growth

Development

Seed coats

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Meristems

Mature sporophyte develop from seedlings

Hierarchy of structures in a mature plant

Primary Growth

Primary Tissues

Secondary Growth

Major groups of Angiosperms

Eudicots

Monocots

Root system adaptations

Major functions

Eudicots

Taproots

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Monocots

fibrous roots

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Three zones of root growth

  1. Region of cell division
    • RAM and root cap
    • RAM contains cells that ar dividing
    • Quiescent center keeps nearby cells undifferentiated
    • Root cap embedded in mucigel
      • Mucigel is a slimy substance that covers the root cap of the roots of plants.
  2. Region of elongation
    • cells extend by uptake of water
  3. Region of maturation
    • root cell differentiation  and tissue specialization
    • identified by presence of root hair
      • water and mineral uptake

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Root Internal Structure

Eudicot root

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Monocot Root

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The shoot system

Stem and leaf adaptations

Shoots are modular with 4 parts

  1. Stem node
    • leaves or branches emerge
  2. Internode
    • stem between adjacent nodes
    • elongation
  3. Leaf
  4. Axillary Meristem
    • generate axillary buds
    • can produce flowers or branches 
      • Lateral shoots
    • New branches bear SAM at their tips

Shoot Tip

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Leaf anatomy

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Leaf adaptation

Leaf venation

Eudicot

Monocot

Stem

Primary growth

Eudicot Stem

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Lateral Meristems

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Monocot stem

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Comparison between Plant types

Leaves

Eudicot

Monocot

Roots

Eudicot

Monocot

Stems

Eudicot

Monocot

Primary Growth

Secondary Growth

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Chapter 36

Overview of plant behavioral responses

Responses to internal and external stimuli

Internal

External

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Plant Behavior

Involves internal and external stimuli

Phototropism

Gravitropism

Thigmotropism 

Regulation of plant growth

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Hormones

Hormones control

Hormones of two broad categories

Auxins

Effects of auxin

Promotes
Inhibits

Cytokinins

Effects of Cytokinins

Promotes
Inhibits

Gibberellins (giberellic acids)

Effects of Gibberellins

Promotes

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Brassinosteriods

Effects of Brassinosteriods

Promotes
Inhibits

Abscisic Acids (ABA)

Effects of ABA

Promotes
Inhibits

Ethylene

Effects of Ethylene

Promotes

Seed germination

Internal

External

Generalized Seed

Seedling

Chapter 37

Nutritional resources of plants

Essential elements

Macronutrients

Micronutrients

Limiting factors

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Chapter 38

Transport of materials in plants

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Importance of water

Properties of water

Principles of movement

Tissue-level transport

Cellular water content

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Water potential

Water (and soil mineral) movement through the plant

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Xylem

  1. Xylem parenchyma cells
  2. Thick-walled supportive fibers
    • may be alive or dead at maturity
  3.  vessel elements
    • Speacilized water conducting cells and are always dead and empty of cytosol when mature
    • Wide tubes
  4. Tracheids
    • tracheory elements
      • Rich in lignin which offers strength, durability, and water proofing
    • Narrow tubes

Stomata

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Mechanisms of Guard cells

 

Causes of water loss

Transpiration Stream

Unidirectional movement
Only goes UP!

C-A-T Mechanism

Solute movement in plants

Long-distance transport in phloem

Phloem Structure

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Pressure Flow Hypothesis

At source
  1. Companion cells "pump" sucrose into STM (STP expended)
  2. As sucrose concentration increases in STM, water potential (concentration) decreases within STM
  3. Adjacent Xylem has higher water potential than STM, H2O moves into STM by osmosis

Bulk flow of Sucrose
Higher Pressure > lower Pressure

At sink
  1. Companion cells unload sucrose (ATP expended)
  2. Sucrose converted into starch for storage in root cortex
  3. Without sucrose, higher H2O potential in STM
  4. H2O moves from STM to adjacent Xylem by osmosis

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Similarities Between Translocation and Transpiration

Translocation Transpiration
  • Phloem
  • Bidirectional
  • Must expend ATP energy by plant
  • Xylem
  • Unidirectional
  • Sunlight energy (no expenditure by plant)

Chapter 39

Reproduction in plants

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Flower and Sexual Cycle

"Ideal" Flower

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Sexual Cycle

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Male

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  1. 2N microspore mother cell
  2. meiosis/cytokenesis
  3. 4 1N microspores
  4. Each: mitosis/cytokenesis
    unequal and incomplete
  5. 1N Generating cell
    1N Tubecell

Male Gametophyte

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Pollination

Pollinating Agents

Mechanisms utilized for transfer of pollen

  1. Wind
    • small/lightweight pollen
  2. Water
    • Transfer with a few aquatic plants
  3. Animals
    • Majority of plants
    • Utilized as a "trick and reward" system
    • nectar, colors, and aromas to attract animals

Female

Ovule Development

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  1. 2N megaspore mother cell
  2. meisos/sytokenesis
  3. 4 1N Megaspores
  4. 3 degrade
  5. 2N Functional megaspore
  6. Series of 3 mitosis/cytokenesis cycles
    Incomplete and unqueal
  7. 7-celled embryo sac
    8 nuclei

Female gametophyte

 

embryo-sac.gif

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Embryo sac

Syngamy (fused gametes)

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Seed germination