‘Understanding how roots penetrate hard soils has huge implications for agriculture…’
An international research team has discovered how the signalling hormone ethylene causes roots to stop growing in hard soils. However, once the signal is disabled, roots are able to push through compacted soil.
The work, which is led by a team from the University of Nottingham’s Future Food Beacon, UK, and Shanghai Jiao Tong University, China, has been published in the journal Science.
The researchers say that hard or compacted soils represent a major challenge facing modern agriculture, with reduced root growth potentially cutting crop yields by more than 50%. Europe has over 33 million-hectares of soil prone to compaction, said to be highest in the world. As well as reducing the depth to which a root grows, soil compaction restricts the amount of water and nutrients than can be absorbed.
While it would be thought that hard soil is simply difficult for a root to penetrate, the researchers from nine universities in Europe, China and the US were able to identify that the plant signal ethylene controls root responses to hard soil. The volatile plant hormone ethylene diffuses through aerated soil, however, compacted soil reduces the diffusion, increasing the concentration of ethylene near root tissues. The cellular signalling cascades triggered by too much ethylene stop root growth.
Despite its clear importance for agriculture and global food security, the mechanism underpinning root compaction response had been unclear the researchers said. But using X-ray Computed Tomography scanners, at the University of Nottingham, the researchers have been able to visualise, in situ, how plant roots respond to compacted soils. The team said that the discovery ‘opens up new opportunities to select novel compaction resistant crops.’
Professor Malcolm Bennett from the University of Nottingham School of Biosciences said ‘Understanding how roots penetrate hard soils has huge implications for agriculture, as this knowledge will be critical for breeding crops more resilient to soil compaction.’