Plants responses to a new biophilic lighting system

The LED-sourced CoeLux® lighting system reproduces the effect of natural sunlight entering through an opening in the ceiling, with a realistic sun perceived at an infinite distance surrounded by a clear blue sky. It has already been demonstrated that this new lighting system generates long-term positive effects on human beings; however, there are no investigations so far concerning the plant responses to CoeLux® lighting. We used the model plant Arabidopsis thaliana WT to characterize both morpho-physiological responses and gene expression of the main plant photoreceptors at different light intensities and at different times after the exposure to the CoeLux® light type, using high-pressure sodium lamps as control light type. Furthermore, mutants for the main photoreceptors’ genes were used to evaluate the role of these genes in the response to this peculiar light type. Under the CoeLux® light type, Arabidopsis WT plants showed a delayed life cycle and were significantly smaller than plants grown with control light, showing clear symptoms of light-induced stress. The phytochrome A gene showed to be more expressed in WT plants grown under the CoeLux® light type, while mutants of the phytochrome B and cryptochrome 1 genes showed a reduced lamina-to-petiole ratio under the CoeLux® light type.