Transpiration Flashcards

All 6 cards in this deck

What is transpiration?

The evaporation of water from the leaf cells and its diffusion out of the leaf through the stomata.

What is the transpiration stream?

The movement of water taken in by the roots, up the plant through the xylem, and lost from the leaves.

What is the role of the stomata and guard cells?

To control gas exchange and water loss — guard cells open and close the stomata.

True or false? Stomata are usually almost closed at night.

True. There is no light for photosynthesis, so closing them reduces water loss.

Which four environmental factors affect the rate of transpiration, and what change in each increases the rate?

Higher temperature, higher light intensity, more air movement and lower humidity all increase the rate.

What are the steps to calculate the rate of transpiration from water uptake data?

e.g. a shoot takes up $6$ cm$^3$ of water in $3$ hours

1. Find the volume of water taken up: $6$ cm$^3$
2. Divide by the time taken: $6 \div 3$
3. Give the answer with units: $2$ cm$^3$ per hour