3.3 transport in plants Flashcards
Function of the xylem
- food transport
- structural support
Where is the xylem found in the root
the centre (star shaped)
Where is the xylem found in the leaf
inside
Where is the phloem found in the root
outside
Where is the phloem found in the leaf
outside
Function of the phloem
transport organic compounds
Function of lignified cell walls
adds strength to withstand the hydrostatic pressure so the vessels do not collapse
Function of no end cell plates
allows mass flow of water and dissolved solutes
What is the xylem made up of
- tracheids
- vessel elements
- xylem parenchyma
- sclerenchyma cells
Define transpiration
loss of water vapour from the stomata to its envrionment by the process of evaporation
What drives the transpiration stream
water potential gradient
How does temperature affect the rate of transpiration
- greater kinetic energy of the molecules = greater evaporation
How does humidity affect the rate of transpiration
- higher the humidity = decreases water vapour potential gradient
- decreases the rate of evaporation of water vapour
How does wind speed affect the rate of transpiration
- at the beginning the wind removes more water vapour from the boundary layer on the leaf
- air is replaced with more humid air so increases water potential gradient
What is the symplastic pathway
- water travels in the cytoplasm or plasmodesmata
- moves via osmosis
