Wei, Xiaoqing; Li, Xinyue; Huang, Guoqiang; Sparks, Erin. E.; Zhang, Yushi; Zhang, Mingcai; Ren, Tusheng; Li, Baoguo; Zhou, Hu
Abstract
Soil compaction is a prevalent physical constraint that adversely affects root development. Brace roots are critical for providing structural support and facilitating nutrient and water uptake of maize, but the responses of brace roots to soil compaction are understudied. In this study, we examined maize brace root development under three soil compaction levels created by different wheeling intensities: no wheeling passes as a control, five, and ten wheeling passes of compaction. Increased wheeling intensity significantly increased soil bulk density, shear strength, and penetration resistance while decreasing gas diffusivity. These changes promoted brace root development, increasing node number, root number, diameter, angle, and lateral root branching density. Soil compaction and the associated changes in soil physical properties significantly affected hormone content at maize nodes, with increased 1-aminocyclopropane-1-carboxylic acid and abscisic acid that were positively correlated with brace root development. Meanwhile, compaction reduced cytokinin content, which was negatively correlated with brace root development. These results demonstrate that maize brace roots exhibit adaptive morphological responses to soil compaction, which was mediated by changes in nodal hormone content. This study provides insights into hormone-mediated maize root plasticity under compaction stress, offering potential strategies for improving crop resilience. Further studies are need to explore the mechanisms that soil compactions influence the hormone of maize.
Soil compaction affects hormone content and maize brace root development.pdf
