Hydrophytes/Xerophytes Flashcards
What are hydrophytes?
Plants adapted to live in aquatic habitats. They don’t need to reduce water loss however, they need adaptations to live with a low oxygen level.
What is an example of a hydrophyte?
Water lillies
How do air spaces help hydrophytes?
They help the plant float, increasing the amount of light/oxygen they recieve.
Can also store oxygen for respiration.
How do the stomata differ in hydrophytes?
Only present on the upper surface of floating leaves to maximise gas exchange.
How do flexible stems and leaves help hydrophytes?
Supported by the water around them so don’t need rigid stems,
Flexibility also prevents them from being damaged by water currents.
Why do hydrophytes have few root hair cells?
Less water absorption is needed than other plants.
Why do hydrophytes have a large surface area to volume ratio?
So they can absorb lots of light
Why do hydrophytes’ seeds/shoots grow quickly?
In order to get to the oxygen in the air needed for photosynthesis.
Why do hydrophytes have a thin waxy cuticle?
Don’t need to reduce water loss
Why are stomata always open in hydrophytes?
More gas exchange can occur
Help lose water
What are aerenchyma and how do they help hydrophytes?
Tubes that take oxygen in air down to the roots where respiration occurs for ATP so active transport of mineral ions can occur.
What are xerophytes?
Plants adapted to live in dry climates. Their adaptations prevent them losing to much water by transpiration.
How can stomata be adapted in xerophytes?
Stomata can be sunk in pits, sheltering it from wind, slowing down transpiration.
Can close stomata at hottest times of day when transpiration is at it’s highest.
How does a layer of hair on the epidermis help xerophytes?
Traps a moist layer of air around the stomata, called a boundary layer, reducing the water potential gradient between the air and leaf.
How does coiling their leaves when it’s hot/windy help xerophytes?
Traps moist air.
Reduces exposed surface area for losing water.
Protects stomata from wind.
