Large amounts of ethylene signals soil compaction
It is difficult to shovel a shovel in compacted soil and the roots of plants seem to have the same problem when they grow in compacted soil. Pandey et al. found that the problem is not, however, physical resistance, but growth inhibition through a signaling pathway. The volatile vegetable hormone ethylene will diffuse through the aerated soil, but the compacted soil reduces this diffusion, increasing the ethylene concentration close to the root tissues. The cell signaling cascades triggered by too much ethylene prevent root growth. Therefore, gas diffusion serves as a reading of soil compaction for plant roots that grow in search of productive nutrition.
Science, this problem p. 276
Abstract
Soil compaction represents a major challenge for modern agriculture. Compaction is intuitively designed to reduce root growth, limiting the roots’ ability to penetrate harder soil. We report that the growth of roots in compacted soil is instead actively suppressed by the volatile hormone ethylene. We found that mutant Arabidopsis and rice roots that were insensitive to ethylene penetrated the compacted soil more effectively than wild type roots. Our results indicate that soil compaction reduces gas diffusion through the reduction of air-filled pores, causing ethylene to accumulate in the root tissues and trigger hormonal responses that restrict growth. We propose that ethylene acts as an early warning signal so that the roots avoid compacted soils, which would be relevant for research in the improvement of crops resistant to soil compaction.