UV protective coatings: A botanical approach

Solar UV radiation is harmful to many biological systems, as well as all kind of technical applications. UV protective coatings are commonly utilised to shield many susceptible substances. In an attempt to learn from nature we demonstrate that for the Pinus mugo subsp. mugo (dwarf mountain pine) the cuticular wax layer provides UV protection. This biological coating contains chromophores that absorb UV radiation in such a way that it removes the most harmful UV-B and UV-A from the solar spectrum received by the plant and does not lower the received PAR (photosynthetically active radiation). In addition, the P. mugo grown at high elevations in the Alps has a cuticular wax coat that also contains fluorsphores, which convert the harmful solar UV into blue light. This additional blue light can be utilised for photosynthesis in low-light conditions, which gives the P. mugo ecological advantage over other Alpine species. The principle of turning useless or even harmful radiation into useful energy sets an example for new biological based coatings.