Computational morphomechanics of growing plant roots

The morphogenesis of plant organs and tissues has fascinated scientists for centuries. However, it remains a challenge to quantitatively decipher the biomechanical mechanisms underlying the morphological evolutions of growing plants. In this study, we investigate the formation, optimization, and evolution mechanisms of plant roots through biomechanical morphogenesis. A transdisciplinary computational framework is established based on the adaptive design domain topology optimization method. Two typical kinds of root systems are studied for illustration, including the taproot and the fibrous systems. The effects of coupled biomechanical and environmental factors on the growth and form of the root systems are revealed. It is found that the morphological evolutions of both systems tend to maximize the transport efficiency of water and nutrients. Lateral roots are constantly generated, forming a hierarchically branched layout. The thickness and concentration of roots depend on the growth history, while the growth directions of root caps are regulated by geotropism, hydrotropism, and growth inertia. These results are consistent with experimental observations. This work not only helps understand the topological formation of root systems, but also provides a quantitative tool for exploring the structure-property-function interrelations of living systems.