A potometer is an apparatus used to measure the rate of water loss, or transpiration, from a plant. The rate of transpiration is determined by measuring the drop in water level in a graduated tube over a period of time. The drop in water level is caused by the plant absorbing water to replace an equal volume of water lost by transpiration.
The apparatus is mounted on a strong backing plate and consists of a capillary tube with a millimetre scale, connected via a three-way tap to a syringe. A cut shoot is connected to third outlet.
| Type | Potometer |
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The hardest thing with potometers is making an air tight seal with the plant stem.The beauty (apart from the value) of this design is you can attach the plant stem on the tube under water separately from the apparatus this means you can make a good seal by wrapping elastic bands round several times. All you have to do then is to push the other end of the tube on the apparatus (also under water).
