Structural origins of morphing in plant tissues

Plant tissues are able to generate complex movements via shape modifications. These effects are tightly related to distinctive multi-scale composite architectures of the plant material, and can therefore largely be interpreted by composite mechanics principles. Here, we propose a generic framework for the analysis and prediction of the shape morphing of intricate biological composite materials, arising from changes in humidity. We have examined in depth the hierarchical structures of three types of seed pods for which we propose a theoretical scheme that is able to accurately simulate the relevant shape deformations. The validity and generality of this approach are confirmed by means of laboratory scale synthetic models with similar architectures leading to equivalent morphing patterns. Such synthetic configurations could pave the way to future morphing architectures of advanced materials and structures.