Hydrotropism’ is the directional growth of a plant part in response to water. For example, roots show hydrotropism as they grow towards water in the soil and are positively hydrotropic.

An experiment to demonstrate hydrotropism is as follows:

1. A porous pot filled with water is taken and inserted in a tub filled with dry sand.
2. A freshly germinated pea seedling is sowed in the sand.
3. As water is not available in sand, the root growing will bend towards the porous pot filled with water.
4. A hydrotropic curvature of the root is observed as it grows towards water.
5. This bending of root shows the movement in response towards water.