Micro-spectroscopy of chloroplasts in protoplasts from Arabidopsis thaliana under single- and multi-photon excitations

Ultrafast laser pulses are known to generate impacts on specimens in ways much different from cw illumination in the applications of confocal microscopy. In this study, protoplasts from Arabidopsis thaliana are employed as the samples to compare the effects induced by single- and multi-photon excitations under confocal imaging configuration. Through time-lapsed micro-spectroscopy we are able to characterize the differences in photo-bleaching and the evolution of fluorescence spectra of chloroplasts thus induced. These differences may be attributed to the disruption of chained reaction as a result of multi-photon excitation in photosynthesis.