Leuther Frederic, Iseskog Daniel, Keller Thomas, Larsbo Mats, Pandey Bipin K, Colombi Tino
Chair of Soil Physics, University of Bayreuth, Bayreuth, Germany.
Department of Soil and Environment, Swedish University of Agricultural Sciences (SLU), Uppsala, Sweden.
Plant Cell Environ. 2025 Feb;48(2):1608-1620. doi: 10.1111/pce.15219. Epub 2024 Oct 27.
Root circumnutation, the helical movement of growing root tips, is a widely observed behaviour of plants. However, our mechanistic understanding of the impacts of root circumnutation on root growth and soil exploration is limited. Here, we deployed a unique combination of penetrometer measurements, X-ray computed tomography and time-lapse imaging, and cavity expansion modelling to unveil the effects of root circumnutation on the mechanical resistance to soil penetration. To simulate differences in circumnutation amplitude and frequency occurring among plant species, genotypes and environmental conditions, we inserted cone penetrometers with varying bending stiffness into soil samples that were subjected to orbital movement at different velocities. We show that greater circumnutation intensity, determined by a greater circumnutation frequency in conjunction with a larger circumnutation amplitude, decreased the mechanical resistance to soil penetration. Cavity expansion theory and X-ray computed tomography provided evidence that increased circumnutation intensity reduces friction at the cone-soil interface, indicating a link between root circumnutation and the ability of plants to overcome mechanical constraints to root growth. We conclude that circumnutation is a key component of root foraging behaviour and propose that genotypic differences in circumnutation intensity can be leveraged to adapt crops to soils with greater mechanical resistance.
根的回旋转头运动，即生长中的根尖的螺旋运动，是植物中广泛观察到的一种行为。然而，我们对根的回旋转头运动对根系生长和土壤探索影响的机制理解有限。在这里，我们采用了针入度测量、X射线计算机断层扫描、延时成像以及孔洞扩张建模等独特组合方法，来揭示根的回旋转头运动对土壤穿透机械阻力的影响。为了模拟植物物种、基因型和环境条件之间回旋转头幅度和频率的差异，我们将具有不同弯曲刚度的锥形针入仪插入以不同速度进行轨道运动的土壤样本中。我们发现，由更高的回旋转头频率和更大的回旋转头幅度共同决定的更大回旋转头强度，降低了土壤穿透的机械阻力。孔洞扩张理论和X射线计算机断层扫描提供了证据，表明回旋转头强度的增加会降低锥形与土壤界面处的摩擦力，这表明根的回旋转头运动与植物克服根系生长机械限制的能力之间存在联系。我们得出结论，回旋转头运动是根系觅食行为的关键组成部分，并提出可以利用回旋转头强度的基因型差异来使作物适应具有更大机械阻力的土壤。
