Quiz 5 Flashcards
Transpiration
Loss of water vapor by plant parts; usually the leaves
Stomata
• Epidermal openings typically located on the undersides of the leaves
- most water vapor is lost through this
Adaptations
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Plants, like animals are not well adapted to retain the water they take in and as a result, lose a great deal of water daily.
This is especially true of plants in hot or arid environments and as a result plants have evolved several adaptations to assist in regulating transpiration.
- one such adaptation seen in most plants is the GUARD CELL
Guard cell
Each stomata opening on a leaf is surrounded by two guard cells, which serve to open and close stomata and regulate water loss
Other adaptations that play a role in preventing water loss
- thickened cuticle
- waxy coating on leaves
- reduced leaves
- modifications to the photosynthetic pathway that allow certain species to keep their stomata closed during the day
How do you think each of the environmental factors influence transpiration rate ?
- light: water will evaporate at a moderate rate
- heat: water will be evaporated from the plant more rapidly than any other environmental factor
- air flow: water will evaporate less than any other environmental factor
- humidity: water will evaporate at a lesser rate than light / head due to the moisture already in the air
What would be an impact of each of the environmental factors of the stomata
- light: will cause an opening of the stomata
- heat: will more rapidly cause an opening of the stomata so the water vapor can transpire
- air flow: won’t have much of an affect on the stomata
- humidity: will have little affect on the stomata
Why might a plan keep us stomata closed under dry conditions
Because it needs to retain its water to survive
What would be problematic with keeping the stomata closed
- it could become too full of water
- it wouldn’t be able to exchange gases (oxygen & CO2)
