Root pressure is measured by an instrument called an auxanometer. The auxanometer measures plant growth as well as the pressure developed within the xylem cells of roots.

Instrument to Measure Root Pressure:

Potometer:
A potometer is the instrument used to measure root pressure in plants. It is a device that allows the observation of water movement in plants. By measuring the rate of water uptake by a plant, the potometer can indirectly determine the root pressure.

How Potometer Measures Root Pressure:
- The potometer consists of a chamber filled with water and a plant cutting with its cut end submerged in the water.
- As the plant takes up water through its roots, the water level in the chamber decreases.
- By measuring the rate of water uptake over time, the potometer can calculate the root pressure exerted by the plant.

Advantages of Using a Potometer:
- Potometers are simple and easy to use, making them ideal for measuring root pressure in plants.
- They provide real-time data on water uptake, allowing for accurate measurements of root pressure.

Limitations of Using a Potometer:
- Potometers may not be suitable for all plant species, as some plants may not perform well in the device.
- External factors such as temperature and humidity can affect the accuracy of the measurements taken by a potometer.
In conclusion, a potometer is a valuable instrument for measuring root pressure in plants. By providing real-time data on water uptake, potometers can help researchers better understand the mechanisms behind root pressure and its significance in plant physiology.