Michaela Eder ist Gruppenleiterin am Max-Planck-Institute of Colloids and Interfaces, Department of Biomaterials, in Potsdam/Deutschland.
Abstract:
Our group studies biological materials within their ecological context in order to understand how plant material properties are fine-tuned to a given environment. Currently we focus our research on fruits of the Australian plant species Banksia attenuata sampled in different regions over a climatic gradient. The material of the Banksia follicles (seed pods) is particularly interesting since the seeds are stored on the plants for several years. Seeds are then released after fire and subsequent rain.
This seed release mechanism requires both long-term (dimensional) stability and the ability to respond to short term stimuli for triggered opening. We were able to identify a self-sealing mechanism to keep the woody fruits intact for many years. Most interestingly, we observed that opening temperatures change for the same species as the habitat becomes hotter and drier, showing that environmental factors are encoded within the follicle material. Follicle geometry controls fruit opening in a surprisingly low temperature range of ~ 55 (south) and ~75 °C (north).
After this initial opening a humidity driven bilayer, requiring several wetting and drying cycles, becomes active and allows for seed release. This presumably ensures that optimal conditions for germination are present. From a biomimetic point of view detailed knowledge about material properties of the follicles can be potentially useful for the development of environmental friendly, biomimetic flame retardants, the design of dimensional stable bio-based construction materials or the development of robust fire-sensors.