Model updating of flowering snapdragon (Antirrhinum litigiosum) biomechanical responses to vibro-acoustic stimuli

Abstract

The combined variation in gene expression and environmental conditions during flower development can result in phenotypic differences in shape, size, and material composition. Biomechanical responses in flower organs due to external stimuli can be mechanically measured at various levels. Here, we investigate snapdragon (Antirrhinum litigiosum) response to vibro-acoustic stimuli by an interdisciplinary model updating framework. In a climate-controlled setup, sweep signals and artificial signals representative of plant pollinator species were given as excitation input through a loudspeaker to a set of plants; vibrations of the flower organs were measured by laser Doppler vibrometry. Geometric features of the plants were identified using LiDAR combined with photogrammetry, while the density distribution in the flower organs and internal dimensions were estimated using micro-computed tomography scans. A computer model using finite element method was used to identify material properties of the flower organs by combining time domain measurements and dimensional classification. Results demonstrate density and stiffness gradient in the corolla contributing to a modal activity that is adaptive to local conditions and pollinators, but resilient against external noise. The framework outlined herein may give clues to which pollinators induce early-plant responses. [The authors acknowledge the support of the Human Frontier Science Program (HFSP) grant RGP0003/2022.]