Division of Agricultural and Environmental Sciences, Gateway Building, Sutton Bonington Campus, University of Nottingham, Leicestershire, LE12 5RD, UK.
Sustainable Soils and Grassland Systems Department, Rothamsted Research, West Common, Harpenden, Hertfordshire, AL5 2JQ, UK.
Sci Rep. 2017 Nov 1;7(1):14875. doi: 10.1038/s41598-017-14904-w.
The rhizosphere is the zone of soil influenced by a plant root and is critical for plant health and nutrient acquisition. All below ground resources must pass through this dynamic zone prior to their capture by plant roots. However, researching the undisturbed rhizosphere has proved very challenging. Here we compare the temporal changes to the intact rhizosphere pore structure during the emergence of a developing root system in different soils. High resolution X-ray Computed Tomography (CT) was used to quantify the impact of root development on soil structural change, at scales relevant to individual micro-pores and aggregates (µm). A comparison of micro-scale structural evolution in homogenously packed soils highlighted the impacts of a penetrating root system in changing the surrounding porous architecture and morphology. Results indicate the structural zone of influence of a root can be more localised than previously reported (µm scale rather than mm scale). With time, growing roots significantly alter the soil physical environment in their immediate vicinity through reducing root-soil contact and crucially increasing porosity at the root-soil interface and not the converse as has often been postulated. This 'rhizosphere pore structure' and its impact on associated dynamics are discussed.
根际是受植物根系影响的土壤区域，对植物的健康和养分获取至关重要。所有地下资源都必须经过这个动态区域，才能被植物根系捕获。然而，研究未受干扰的根际一直非常具有挑战性。在这里，我们比较了在不同土壤中，根系系统发育过程中完整根际孔隙结构的时间变化。高分辨率 X 射线计算机断层扫描（CT）用于量化根发育对土壤结构变化的影响，其尺度与单个微孔和团聚体（µm）相关。在均匀填充土壤中对微尺度结构演化的比较突出了穿透根系系统对周围多孔结构和形态的改变。结果表明，根的影响结构区可以比以前报道的更局部（µm 尺度而不是 mm 尺度）。随着时间的推移，生长中的根系通过减少根土接触，极大地增加根土界面的孔隙率，而不是像以前经常假设的那样反过来，从而显著改变其附近的土壤物理环境。讨论了这种“根际孔隙结构”及其对相关动力学的影响。
