3.1.3 Plant Transport – Plant Adaptations Flashcards
(10 cards)
What is a xerophyte?
A plant that lives in dry conditions and is adapted to reduce water loss/increase water uptake.
State 2 examples of xerophytes.
Marram grass and cactus
Explain how each adaptation can reduce water loss in marram grass:
- Rolled leaf
- Thick waxy cuticle
- Stomata on inside of rolled leaf
- Stomata in pits and covered with hairs
- Stomata closed at night
Rolled leaf – traps water vapour to reduce concentration gradient.
Thick waxy cuticle – impermeable to water and increases diffusion distance of water.
Stomata on inside of rolled leaf – stomata located in an area that has a high water potential (due to trapped water potential) therefore it reduces the water potential gradient.
Stomata in pits and covered with hairs – the pits and hairs trap water vapour so reduces the concentration gradient.
Stomata closed at night – stomata closed when photosynthesis cannot occur, therefore water can not be lost at night.
Explain how each adaptation can conserve water/reduce water loss in a cactus:
- Leaves reduced to spines
- Widespread lateral roots
- Few stomata
- Stomata closed during the day
- Low water potential in cells
Leaves reduced to spines – reduces the surface area to volume ratio to reduce water loss (stem contains chlorophyll to allow photosynthesis).
Widespread lateral roots – increases water uptake.
Few stomata – reduces water loss by transpiration.
Stomata closed during the day – reduces water loss by transpiration (transpiration occurs faster in the day when temperatures are higher)
Low water potential in cells – reduces the water potential gradient.
What is a hydrophyte?
A plant that grows partially or fully submerged in water.
Give an example of a hydrophyte.
Water lily
Why are hydrophytes able to have little or no root system?
They have little or no root system due to it only being required for anchorage. The roots are not involved in water absorption, as the leaves are able to absorb water by osmosis.
Why do hydrophytes have no/little lignified support?
Water is a supportive medium so the hydrophyte doesn’t need lignin.
Where are stomata located on the leaves of hydrophytes? Explain why they are located there.
The stomata are located on the upper epidermis on the leaves. This is because it is the part of the plant that is exposed to air (to allow for gas exchange to occur).
What provides the buoyancy in a hydrophyte?
Large air spaces within the stems and leaves.
