Transport in Plants Flashcards
What is the function of a root hair?
to absorb water and minerals from the soil
How are mineral ions transported into the root hair cells?
via active transport
How are root hair cells adapted for their function?
thill walled, high surface area
Water moves into root hair cells via…
osmosis - soil water has a higher water potential than cell
What is transpiration?
evaporation of water from the surface of a plant
How does temperature effect rate of transpiration?
increases rate of evaporation - water molecules have more kinetic energy (high temp)
How does humidity effect rate of transpiration?
very humid air - smaller conc gradient, slows rate
dry air - increase rate, high conc gradient
How does wind speed effect rate of transpiration?
high speed - blows away water
away vapour from stomata, increase rate
low speed - area around stomata becomes saturated with water, slows rate
How does light intensity effect rate of transpiration?
daylight - stomata is open to supply CO2 for photosynthesis, increases rate
How can we measure the rate of transpiration?
using a potometer - distance bubble travels in a certain time
How do you set up a potometer?
-underwater (prevents air bubbles entering + blocking xylem)
-cut stem of shoot
-put stem into bung, grease joint with Vaseline (prevents water loss + air entry)
-put bung in potometer
-close tap + lift potometer out of water
-leave capillary tube out of water until air bubble forms, then put end of capillary tube in a beaker of water
How can we change a transpiration experiment to investigate different factors?
-windy (hair dryer)
-increase temp
-increase humidity (plastic bag)
-darkness
