Investigating Transpiration Practical Flashcards
How does Light intensity affect transpiration rate?
stomata open when its light to let in CO2 for photosynthesis so more transpiration
How does Temperature affect transpiration rate?
in warmer conditions, water particles have more kinetic energy so they are able to evaporate from the surface of the leaf faster, this increases the water potential gradient between inside and outside the leaf so the transpiration rate is increased
How does Humidity affect transpiration rate?
if air around plants is dry, the water potential gradient is increased so transpiration occurs faster, humid environments the water potential gradient is reduced as there is more water in the atmosphere so the rate of transpiration decreases
How does Air movement affect transpiration rate?
lots of wind blows water molecules away from the stomata increasing the water potential gradient and therefore increasing the transpiration rate
What is a potometer?
measure water uptake by the plant, used to estimate how different facts affect the transpiration rate
What are the considerations for this experiment?
shoot must be cut underwater to prevent air entering the xylem, cut from an angle to increase the surface area available to uptake water, end of capillary tube must stay in water, diameter of capillary tube should be measured, leaves must be dry
What is the first step of measuring the rate of transpiration?
removing the capillary tube from the beaker of water for a short time allows an air bubble to form at the end
What is the second step of measuring the rate of transpiration?
start point of air bubble must be recorded, its position can be pushed back by emptying water from the reservoir using the tap
What is the third step of measuring the rate of transpiration?
using a stopwatch the time it takes for the bubble to move a certain distance can be recorded, the rate is an estimate of the transpiration rate
