Question

Define the following term:

Root pressure.

Answer 1

Root pressure:

1. Root pressure is positive pressure that develops in the xylem channel of some plants due to the metabolic activity of their roots.
2. For this solutes accumulate in the xylem resulting in increased absorption of water.
3. Some active uptake of water in the xylem can also occur.
4. Both result in the development of positive pressure or root pressure.
5. Root pressure is maximum during the early morning in the spring and rainy seasons.
6. Root pressure is little or absent at other times.
7. Root pressure can push water upwards in the xylem with a force of 1 to 2 atmospheres.
8. In many leaves of grass and herbaceous plants, droplets of water can be seen on early morning overleaf tips and leaf margins. The phenomenon is called guttation, eg. balsam, garden nasturtium, tomato, etc.