Soil penetration by maize roots is negatively related to ethylene-induced thickening

Vanhees, Dorien J.; Schneider, Hannah M.; Sidhu, Jagdeep Singh; Loades, Kenneth W.; Bengough, A. Glyn; Bennett, Malcolm J.; Pandey, Bipin K.; Brown, Kathleen M.; Mooney, Sacha J.; Lynch, Jonathan P.

Abstract

Radial expansion is a classic response of roots to a mechanical impedance that has generally been assumed to aid penetration. We analysed the response of maize nodal roots to impedance to test the hypothesis that radial expansion is not related to the ability of roots to cross a compacted soil layer. Genotypes varied in their ability to cross the compacted layer, and those with a steeper approach to the compacted layer or less radial expansion in the compacted layer were more likely to cross the layer and achieve greater depth. Root radial expansion was due to cortical cell size expansion, while cortical cell file number remained constant. Genotypes and nodal root classes that exhibited radial expansion in the compacted soil layer generally also thickened in response to exogenous ethylene in hydroponic culture, that is, radial expansion in response to ethylene was correlated with the thickening response to impedance in soil. We propose that ethylene insensitive roots, that is, those that do not thicken and can overcome impedance, have a competitive advantage under mechanically impeded conditions as they can maintain their elongation rates. We suggest that prolonged exposure to ethylene could function as a stop signal for axial root growth.

Citation

Vanhees, D. J., Schneider, H. M., Sidhu, J. S., Loades, K. W., Bengough, A. G., Bennett, M. J., …Lynch, J. P. (2021). Soil penetration by maize roots is negatively related to ethylene-induced thickening. Plant, Cell and Environment, https://doi.org/10.1111/pce.14175

• Journal Article Type: Article
• Acceptance Date: Aug 22, 2021
• Online Publication Date: Aug 28, 2021
• Publication Date: Aug 28, 2021
• Deposit Date: Sep 1, 2021
• Publicly Available Date: Aug 29, 2022
• Journal: Plant Cell and Environment
• Print ISSN: 0140-7791
• Electronic ISSN: 1365-3040
• Publisher: Wiley
• Peer Reviewed: Peer Reviewed
• DOI: https://doi.org/10.1111/pce.14175
• Keywords: Plant Science; Physiology
• Public URL: https://nottingham-repository.worktribe.com/output/6138812
• Publisher URL: https://onlinelibrary.wiley.com/doi/10.1111/pce.14175
• Additional Information: This is the peer reviewed version of the following article: Vanhees, D.J., Schneider, H.M., Sidhu, J.S., Loades, K.W., Bengough, A.G., Bennett, M.J., Pandey, B.K., Brown, K.M., Mooney, S.J. and Lynch, J.P. (2021), Soil penetration by maize roots is negatively related to ethylene-induced thickening. Plant Cell Environ., which has been published in final form at https://doi.org/10.1111/pce.14175. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions. This article may not be enhanced, enriched or otherwise transformed into a derivative work, without express permission from Wiley or by statutory rights under applicable legislation. Copyright notices must not be removed, obscured or modified. The article must be linked to Wiley’s version of record on Wiley Online Library and any embedding, framing or otherwise making available the article or pages thereof by third parties from platforms, services and websites other than Wiley Online Library must be prohibited.