Water transport and Transpiration Flashcards
How does water enter the plant?
Through root hair cells via osmosis
Describe the symplast pathway?
Goes through the cytoplasm. (living part of the cell)
They connect via plasmodesmata
It moves through this pathway from cell to cell via osmosis
Describe the apoplast pathway?
Through the cell walls. (non living part)
Walls between cells easily let water diffuse through or goes through tiny holes
The water can carry solutes
It moves down the pressure gradient
What blocks the apoplastic pathway?
casparian strip
Why does the casparian strip help?
Forces water through a cell membrane. These are partially permeable so can control what substances go through. (acts as a filter system)
What helps water to move up the xylem?
Cohesion and tension
What’s the transpiration stream?
water evaporates from the leaves
This creates tension which pulls up more water
As water is cohesive, when some is pulled up, the rest follow
How does adhesion also help transpiration?
Water is attracted to walls of xylem vessels which helps it to rise
Four factors affecting the rate of transpiration?
Light
Temperature
Humidity
Wind
What are Xerophytic plants?
Adapted to reduce water loss
Live in deserts usually
Name some adaptations of xerophytes?
Stomata in sunken pits to keep water potential gradient low
Hairs around stomata to trap moisture to help water potential gradient
Thick waxy cuticle which is waterproof
Spikes instead of leaves to reduce surface area for water loss
Ability to close stomata at hottest time of the day
What name is given to plants that survive in water?
Hydrophilic plants
What adaptations allow hydrophilic plants to survive?
Air spaces in tissue helps with floating
Stomata only on upper side of leaf for floating plants
Flexibility to prevent damage from currents
