Light Produces Calcium Waves in Nature

Abstract

Calcium waves that arise from high intensity 405nm blue light photostimulation in Arabidopsis thaliana have been observed and studied in the Griffing Laboratory to identify photoreceptors and signaling significance. This project attempts to understand when and if this high-intensity 405nm light occurs in nature by analyzing the parameters that lead to high-intensity light in real-life conditions. Our model is that the light not only has to be of a specific wavelength and photon dose, but it also needs to shine on a specific subcellular region, the ER-chloroplast nexus, to get direct stimulation and produce the calcium wave. This research measures photon dose and wavelength required for photostimulation with a microscope-based spectrometer and power meter and whether dew drops or rain drops might focus the light to a subcellular location. It also explores the varied factors that may affect the interaction of light with plant cells to create the photostimulation effect. Experiments analyze the threshold at which photostimulation triggers signaling and correlate these experiments to how sunlight could also trigger signaling in real-life conditions. Other experiments explore the effect of a circadian rhythm in the respective calcium wave. Connections between the observed wavelengths under weather conditions and how the presence of drops increase the power of light support our hypothesis. Structures such as trichomes can also influence the focal point of the light in the plant surface and direct it to the ER-chloroplast nexus at the optimal power to create the calcium wave.