Biosensor safely detects auxin movement along plant roots

Marshall Porterfield, an associate professor of agricultural and biological engineering and biomedical engineering, created the sensor, which utilises black platinum and carbon nanotubes developed at Purdue.

The nanomaterials at the sensor’s tip react with auxin and create an electrical signal that can be measured to determine the auxin concentration at a single point.

The sensor is said to oscillate, taking concentration readings at different points around a plant root. An algorithm then determines whether auxin is being released or taken in by surrounding cells.

‘It is the equilibrium and transport dynamics that are important with auxin,’ said Porterfield, whose findings were published in the online version of The Plant Journal.

A current focus of auxin research is understanding how this hormone regulates root growth in plants growing on sub-optimal soils.

Angus Murphy, a Purdue professor of horticulture and the paper’s co-author, said that worldwide pressure on land for food and energy crops drives efforts to better understand how plant roots adapt to marginal soils. Auxin is one of the major hormones involved in that adaptive growth.