Potometers:

1. To make your own potometer, just bend a 40cm piece of glass tubing a third of the way down. Attach a 10cm piece of rubber tubing to the longer end. Use an appropriate size stopper with a hole in it at the other end of the rubber tube.
Or:you could just buy one from Southern Biological Services.
Then insert a stem with a few leaves into the hole in the stopper. Assemble all this under water so that it contains no air bubbles. Keep the short end of the glass tube in the water and use a needle syringe to insert an air bubble in the glass tube (under water).
Through the process of transpiration the air bubble moves up and along the glass tube. By using a ruler along the long end of the glass tube you can measure the distance travelled over a certain time. To redo the experiment, insert a needle syringe, full of water, into the rubber tubing and the water will push the air bubble back to the opening ready to start again.
2. Use 2M NaCl and a woody stem (approx 10cm diameter) with leaves, and attach multimeter probes at the base of the stem and 3/4 of the way up. The voltage increases until the NaCl reaches the second probe.

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