Xerophytes & Hydrophytes Flashcards
1
Q
What are mesophytes?
A
Plants that are able to take up sufficient water to replace transpired water vapour (most plants).
2
Q
What are xerophytes?
A
Plants that live in areas where water lost via transpiration is greater than the amount taken up by the roots.
They have structural and physiological adaptations to combat this.
3
Q
What are the adaptations of xerophytes?
A
- Smaller leaves - reduces SA for water loss
- densely packed mesophyll / thick waxy cuticle - prevents water loss via evaporation
- closed stomata to prevent water loss
- hairs and pits - traps moist air, lowering the water vapour potential
- leaves can be rolled to reduce exposure of stomata to atmosphere, trapping air
- thick leaves rather than broad leaves - minimises SA
- spines - protects the plant from small mammals that can remove water from the plant
4
Q
What are the adaptations of Marram grass?
A
- hinge cells - lose turgidity and collapse in dry conditions - allowing the leaf to roll up
- small, thick outer epidermis with no stomata
- stomata in pits to trap air with moisture close to the openings
- hairs to trap water vapour - lowers the water potential gradient
5
Q
What are some examples of xerophytes?
A
- conifers
- marram grass
- cacti
6
Q
What are hydophytes?
A
Plants that live either partially or fully submerged in water that may have issues with O2 uptake.
7
Q
How are hydrophytes adapted to live in their conditions?
A
- very thin / absent waxy cuticle as water does not need to be conserved
- constantly open stomata on upper surface - maximises gas exchange
- wide, flat leaves - large SA for light absorption
- some contain air sacs - enable leaves to stay afloat
- large air spaces - making leaves and stems more buoyant
- reduced veins - reduced xylem as water transport is not necessary
- reduced root systems - nutrients are also extracted through tissue from the surrounding water
8
Q
What are some examples of hydrophytes?
A
- water lilies
- duckweed
- bulrushes
