How can you measure the rate of transpiration in a potted plant?

Question

it can only be with a small branch of the plant..

=]

Answer 1

it is immeasurable i think.

Answer 2

I can think of one way:

1. Gently place a clear polythene bag over the plant.

2. Seal the polythene bag very well. Only the stems and leaves should be in the bag. The roots and the soil should not be in the bag, as this will interfere with the experiment.

Place the plant in a well-lit area.

3. Every hour or so, measure the amount of water that is caught in the bag. You can do this by quickly removing the bag, then catching the water in a graduated cylinder, then quickly resealing the bag over the plant again.

4. Record data. The amount of water caught every time period is the average rate of transpiration for that time period.