Roots grow in a complex soil environment, which exhibits spatial and temporal variability in structure. The soil conditions such as soil strength, water and nutrient availability present significant challenges to root growth. Roots and in particular root apex must sense the physical and chemical characteristics of these changes, to optimize the development of root system. Even if the influence of soil strength on root growth and root reorientation are well described, the influence of root apex comprising root cap and its production is not well understood. In this study we developed a model experimental medium and applied an interdisciplinary approach to investigate the implication of root cap in the response to medium strength. We focus our studies on the in vivo analysis of the Arabidopsis thaliana root growth dynamics and root trajectory following the contact of the root apex with a permanent obstacle, provided by a lower harder layer of Phytagel medium and which is able to block the initially straight root trajectory. In response to contact with the harder layer, the root apex reorientation, which might be interpreted as buckling effect, is preceded by a decrease of root growth rate, illustrating an active root response. Interestingly, the root growth of Arabidopsis fez-2 mutants, which exhibit a reduction of root cap cell layers, is less affected and root tip reorientation occurred progressively. This response could be interpreted both as a better resistance to buckling and a higher sensitiveness to strength of fez-2 mutant. Conversely, smb-3 (SOMBRERO) roots, which exhibit an increased number of root cap cells, exhibit a S-shape in response to contact with the harder layer. This could be interpreted as higher sensitivity to buckling. Thus, the present study highlights the influence of root cap shape and integrity on root mechanical response.