Factors affecting transpiration

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Factors affecting transpiration
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Factors affecting transpiration
Factors Transpiration
Humidity Decreases Increases
Temperature Increases Increases
Wind Increases Increases
Light Increases Increases
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Higher conc. of water vapour (100 saturated)
In plastics bag 90 humidity
No plastics bag 70 humidity
The drier the air, the steeper the concentration
gradient, the faster the rate of transpiration.
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Factors affecting transpiration
Factors Transpiration
Humidity Decreases Increases
Temperature Increases Increases
Wind Increases Increases
Light Increases Increases
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night time
day time
Guard cells turgid Stoma Opens
Guard cells flaccid Stoma Closes
Stoma
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Think about it!!

• Why placing the vegetables in a plastic bag helps
  to reduce transpiration?
• It helps to keep the humidity of the air
  surrounding the vegetables high.

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Wilting
Rate of transpiration gt rate of absorption of
water
What happens to the leaves when they wilt?
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Wilting

• How does wilting benefits the plants?
• When leaves fold up, the surface area exposed to
  the sunlight is reduced.
• Stomata closes
• Transpiration decreases

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Wilting

• Disadvantages of wilting
• Stomata closes
• Carbon dioxide cannot diffuse into the leaves
• Carbon dioxide becomes the limiting factor for
  photosynthesis

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How to reduce transpiration?
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Normal condition
Desert plant
Guard cells
Guard cells
Lower epidermis
Lower epidermis
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Guard cells
Habitat of marram grass
Leaves of marram grass
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Hawaii Silversword
Flowers
Leaves
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Guard cells
Leaves covered with silver hairs
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Desert plant

• Adaptations
• Sunken stomata
• How it helps
• The enclosed region around the stomata helps to
  retain water vapour
• increases humidity

Guard cells
Lower epidermis
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Guard cells
Adaptations Functions
Leaves curved up Reduce exposure to wind and high temperature
Hairs surround grooves Traps water vapour
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Adaptations- Leaves covered with silvery white
hair
How it helps -Reflect light lowers
temperature of the leaves