A Prototypical Conjugated Polymer Regulating Signaling in Plants

The use of nanomaterials has been very recently introduced in plant biotechnologies, for both the monitoring and the enhancement of plants functions. Several functional interfaces between living plants and nanotechnology have been successfully reported for diverse applications, from sensing to photosynthesis and energy production and from modulation of physiological activity to controlled delivery of chemicals. In this work, a photoactive, biohybrid interface based on a prototypical semiconducting polymer, sensitive to green light, and Arabidopsis thaliana plants is reported. Optical excitation of polymer beads is shown to deterministically regulate the Arabidopsis stomatal aperture, the leaf pores which regulate the plant carbon dioxide uptake, oxygen release, and transpiration processes. Moreover, it is observed that excitation of bio-polymer hybrid interfaces optically modulates the cytosolic calcium ions concentration, which is involved, as a second messenger, in the regulation of stomatal movements. The results support the possibility to employ light-responsive organic materials to regulate on demand the physiological activity of plant systems, in a drug-free, touchless, and easily controllable way. When transferred to the field, this strategy may represent an innovative approach to optimize the exchange of gases and water loss of plants, and to improve the plant resilience toward environmental constraints.