Plant roots 'have a sense of touch'Study finds they can feel their way past obstacles

01 March 2008

Plant roots have a sense of touch and are able to ‘feel’ their way past obstacles in the soil, a study has shown.

The discovery explains how plants colonise poor soils and germinating seedlings burrow down into the earth without dislodging themselves.

Roots are covered with a fuzzy coat of hairs which act as sensitive ‘fingers’, researchers found.

The root hairs explore the soil in much the same way as a person trying to navigate in the dark.

Root hairs

When they encounter an obstacle, such as a stone, they feel their way around until an opening is discovered through which growing can continue. In the meantime, the gripping hairs anchor the plant in the soil.

‘We have identified a growth control mechanism that enables these hairs to find their way and to elongate when their path is clear,’ said study leader Professor Liam Dolan, from the John Innes Centre in Norwich.

The mechanism uses a protein at the tip of the root hairs to stimulate the uptake of calcium from the soil, said the researchers.

Unpromising soils

Calcium then stimulates more activity by the protein. When an obstacle blocks the hair's path, the cycle is broken and growth starts in another direction.

‘This remarkable system gives plants the flexibility to explore a complex environment and to colonise even the most unpromising soils,’ said Prof Dolan. ‘It also explains how seedlings are able to grow so quickly once they have established.’

Understanding the processes involved could assist the development of crops able to grow in inhospitable environments, say the researchers in the journal Science.

© The Press Association, All Rights Reserved