Chapter 7 BOT3015L Regulation of Gas Exchange of Terrestrial Plants

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Chapter 7BOT3015LRegulation of Gas Exchange of
Terrestrial Plants
Presentation created by Danielle Sherdan All
photos from Raven et al. Biology of Plants except
when otherwise noted
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Today

• Review photosynthesis and bulk transport in
  plants
• Observing leaf morphology
• Examples of highly modified leaves
• Leaf anatomy
• Stomata, adaptations to terrestrial environments
• Stomata aperture changes
• Further understanding of stomata by
  experimentation

• Review photosynthesis and bulk transport in
  plants
• Observing leaf morphology
• Examples of highly modified leaves
• Leaf anatomy
• Stomata, adaptations to terrestrial environments
• Stomata aperture changes
• Further understanding of stomata by
  experimentation

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The main ideas from last weeks look at the
anatomy of the angiosperm plant body
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Photosynthesis primarily occurs in chloroplasts
of leaves
Lilac (Syringa)
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Review of photosynthesis
Triose phosphates
Note that this is a depiction with some gaps and
misrepresentations for summary purposes
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Transport Summary
Aabsorption / assimilation Lloading Uunloading
Iinterchange
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Today

• Review photosynthesis and bulk transport in
  plants
• Observing leaf morphology
• Examples of highly modified leaves
• Leaf anatomy
• Stomata, adaptations to terrestrial environments
• Stomata aperture changes
• Further understanding of stomata by
  experimentation

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Leaf observationsWhat characteristics of leaves
make them well-adapted for their function?
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Today

• Review photosynthesis and bulk transport in
  plants
• Observing leaf morphology
• Examples of highly modified leaves
• Leaf anatomy
• Stomata, adaptations to terrestrial environments
• Stomata aperture changes
• Further understanding of stomata by
  experimentation

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Morphological AdaptationsResponses to Water
Availability
Waterlily (Nymphaea) Note the misnomer,
waterlilies are not in the Liliaceae family
Note the abundant of air spaces.
This plant grows in water.
Modified from Outlaw lecture
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Morphological AdaptationsResponses to Water
Availability
Note large volume-to-surface area ratio ideal for
dry environment
Spines (modified leaves) protect the water-filled
plant body from predation
Ferocactus
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Example of turgor control of quick responses in
highly specialized leaves
Venus fly trap (Diaonaea)
Plants in motion Venus fly trap
Photo by Jean Burns at Hosford bog
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Pitcher plant(Sarracenia)
Example of highly specialized leaves
Photos from www.serracenia.com
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Today

• Review photosynthesis and bulk transport in
  plants
• Observing leaf morphology
• Examples of highly modified leaves
• Leaf anatomy
• Stomata, adaptations to terrestrial environments
• Stomata aperture changes
• Further understanding of stomata by
  experimentation

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Three tissue systems in leaves too
Cross-section, midvein of leaf
Cross-section, blade of leaf
Lilac (Syringa)
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Stomataadaptations to terrestrial environments
Isolated epidermis stained with neutral red
(vital stain that stains compartments of living
cells)
Lilac (Syringa)
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Today

• Review photosynthesis and bulk transport in
  plants
• Observing leaf morphology
• Examples of highly modified leaves
• Leaf anatomy
• Stomata, adaptations to terrestrial environments
• Stomata aperture changes
• Further understanding of stomata by
  experimentation

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Stomata typical of dicots
Stomata typical of monocots
Potato (Solanum)
Maize (Zea)
Scanning electron microscope images
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Stomata and trichome of tobacco (Nicotiana)
Scanning electron microscope image
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Morphological AdaptationsResponses to Water
Availability
Banksia Note sunken stomata.
. . . Sunken stomata increase the distance from
the moist leaf interior to the bulk atmosphere.
Flux Equation!
Modified from Outlaw lecture
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Morphological AdaptationsResponses to Water
Availability
Trichomes and sunken stomata
Oleander (Nerium)
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Today

• Review photosynthesis and bulk transport in
  plants
• Observing leaf morphology
• Examples of highly modified leaves
• Leaf anatomy
• Stomata, adaptations to terrestrial environments
• Stomata aperture changes
• Further understanding of stomata by
  experimentation

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Gas ExchangeOpen Closed Stomata
Photos from Outlaws lab and also featured on
the cover of the scientific journal Archives of
Biochemistry and Biophysics
Fava bean (Vicia)
Stomata animation
Modified from Outlaw lecture
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Gas Exchange (g)Ion Transportstomatal opening

Inside cell
Membrane
Modified from Outlaw WH, Jr. Integration of
cellular and physiological functions of guard
cells. CRC Crit Rev Plant Sci 22 503-529
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Gas Exhange (e)Stomatal swelling
Modified from Outlaw lecture
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Gas Exchange (j)Ion Transportstomatal closing
Modified from Outlaw WH, Jr. Integration of
cellular and physiological functions of guard
cells. CRC Crit Rev Plant Sci 22 503-529
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Gas Exchangeion transportABA action
ABA may be made in roots and transported to
shoots, or made by leaves, or even by guard cells.
ABA activates the anion channel, directly or by
several means indirectly (e.g., via Ca2
signaling).

ABA activates the Kout channel via cytosolic
alkalinization.
Modified from Outlaw WH, Jr. Integration of
cellular and physiological functions of guard
cells. CRC Crit Rev Plant Sci 22 503-529
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Today

• Review photosynthesis and bulk transport in
  plants
• Observing leaf morphology
• Examples of highly modified leaves
• Leaf anatomy
• Stomata, adaptations to terrestrial environments
• Stomata aperture changes
• Further understanding of stomata by
  experimentation

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What internal and external factors likely affect
stomatal aperture?
What are the effects of CO2 on stomatal aperture?
Why do we want to know? How is this important?
About 1700 gallons of water are required to grow
food for one adult in the US per day! (From 1993
National Geographic)
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Experimental Design
The question What are the effects of CO2 on
stomatal aperture?
How can we manipulate CO2 concentration?
One way CO2 NaOH gt NaHCO3 (sodium bicarbonate)
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In notebook and checked before you leave

• Drawings
• Methods
• Data
• Review questions

QUIZ NEXT WEEK