Journal Article

Orchestrated Movement Sequences and Shape-Memory-like Effects in Pine Cones

Poppinga, Simon, Horstmann, Martin, Speck, Thomas

2024

Overview

Hygroscopic seed-scale movement is responsible for the weather-adaptive opening and closing of pine cones and for facilitating seed dispersal under favorable environmental conditions. Although this phenomenon has long been investigated, many involved processes are still not fully understood. To gain a deeper mechanical and structural understanding of the cone and its functional units, namely the individual seed scales, we have investigated their desiccation- and wetting-induced movement processes in a series of analyses and manipulative experiments. We found, for example, that the abaxial scale surface is responsible for the evaporation of water from the closed cone and subsequent cone opening. Furthermore, we tested the capability of dry and deformed scales to restore their original shape and biomechanical properties by wetting. These results shed new light on the orchestration of scale movement in cones and the involved forces and provide information about the functional robustness and resilience of cones, leading to a better understanding of the mechanisms behind hygroscopic pine cone opening, the respective ecological framework, and, possibly, to the development of smart biomimetic actuators.

• Publisher: MDPI AG
• Subject: Actuators / bilayer actuation / Biomechanics / Biomimetics / Cameras / Cones / Deformation / Desiccants / Desiccation / Drinking water / Environmental aspects / Environmental conditions / Evaporation / Experiments / functional robustness / Humidity / hygroscopic movement / Kinematics / Mechanical properties / Physiological aspects / pine cone movement / Pine cones / Plant mechanics / Seed dispersal / Sequences / Shape effects / Shape memory / shape-memory-like effects / Structure-function relationships / tissue mechanics / Wetting