TITLE: Inducing Hydrotropism in Gravitropic Plants

AUTHOR: Sumati Ram-Mohan

SCHOOL: Massachusetts Academy of Math and Science

SCHOOL ADDRESS: 100 Institute Road, Worcester, MA. 01609

The goal of this project is to determine if hydrotropism, a plant’s response to water, can be induced in plants that respond to gravity.. This was accomplished by placing agar blocks containing different concentrations of sorbitol to one side of the root cap of Alaska pea seedlings The sorbitol created a lower water potential on one side of the root cap, thereby stimulating the root to curve away from the sorbitol. After experiencing this gradient in water potentials for 24 hours, the roots were placed on wet filter paper where they curved towards the side opposite to where the sorbitol was placed.

The change in angle of root curvature was measured, and angle measures were found to be significantly higher in plants with unilateral sorbitol applications than in the control group, which had two plain agar blocks on each side of the root cap. These results indicate that the sorbitol influenced curvature in roots, presumably of a hydrotropic nature.

Using the above method, plant varieties other than peas can be tested to determine if hydrotropism is a universal occurrence. The ability to induce hydrotropism in plants without the use of water can have practical applications in the agricultural industry, in places where the conservation of water is necessary.