Biomimicry as a Tool for Studying Plant - Environment Interaction
|Using biomimicry in a new way – instead of imitating nature to better human life, we are imitating nature to better understand nature|
|Maya Kleiman Ph.D.* firstname.lastname@example.org|
|May 6, 2019|
Biomimicry is an approach to innovation that seeks sustainable solutions to human challenges by emulating nature’s time-tested patterns and strategies. Biomimicry uses tools in the fields of materials science and engineering and looks at nature for inspiration. The best-known example in biomimicry concerns the lotus leaf.
The lotus flower is an aquatic plant. The leaves of the plant are known for their super hydrophobicity – “the lotus effect”. This super hydrophobicity is a result of the microstructure on the surface of the leaf rather than the surface chemistry. Scientists and engineers have used the lotus leaf, over the years, as an inspiration to generate super hydrophobic surfaces, mostly for self-cleaning purposes.
Lotus flower Lotus leaf Lotus leaf surface microstructure **
** adapted from G. Carbone and L. Mangialardi, Eur. Phys. J. 16(1):67-76 (2005)
Looking at an interaction between a plant and a living organism such as bacteria, fungus or insect, the initiation of the reaction occurs on the surface. During this interaction many signals are being transmitted between the plant and the other organism – molecules and chemicals are secreted and absorbed from both parties. While these chemical and molecular signals are widely studied in these interactions, one is usually ignored – the physical signal of the microtopography of the surface.
Studying this physical signal using the natural system can be quite challenging as the biological system is very noisy with all the additional molecular and chemical signals. Hence, it is essential to find a different method to study the effect of structure on plant-environment interactions. We are using biomimetics to do exactly that. We are building synthetic surfaces that replicate the structure to less than a micrometer precision. Our surfaces are inert and are currently made from the biocompatible, transparent, inexpensive and commercially available polymer polydimethylsiloxane (PDMS). We prepare the surfaces using a simple method of double molding called soft lithography.
Natural (left) and synthetic (right) leaf surface structure. Middle shows the first mold – the negative of the structure
Grey mold disease in tomatoes and botrytis spores on the leaf surface
Using this model system, we are studying the influence of the surface structure on the fungus
development and possibly pathogenic ability.
Growing spores on both flat and structured PDMS surface we learned that the spores germination is quicker and more efficient on a flat surface – suggesting the plant uses the surface structure as an initial, primitive defense mechanism. Additionally, we learned that the spread of the fungus colony on agar plates is highly dependent on the surface structure. The colony will spread in a circular manner on a flat surface but will spread along the vascular system of the leaf on a leaf structured surface. This phenomenon was observed in the natural system with other fungi and was attributed to the high concentration of sugar and nutrients in the vasculature system. We observed this phenomenon on a synthetic surface where the chemistry and nutrient availability was identical in all directions. Our system proves that the signal obtained by the fungus is structural rather than chemical showing adaptation of the fungus to the plant system and specifically the surface structure.
Spread of botrytis cenerea on agar plates. Colony spreads in a circle in unpatterned plates (lower raw) and along the vascular system of the leaf in the leaf structure patterned plate (upper row)
*Agricultural Research Organization (Volcani Center) Institute of Plant Sciences