Chlorophyll a Fluorescence: A Bit of Basics and History

Chlorophyll (Chi) fluorescence is anon-destructive intrinsic probe of several aspects of oxygenic photosynthesis. In this chapter, the goal is to bring to the readers the basics of Chi fluorescence, a bit of history, it’s potential in understanding primary photophysical events (excitation energy transfer; charge separation), and secondary reactions (electron transport). This chapter is an extension of an earlier overview by the author (Govindjee, 1995). References are made to selected original and historical papers and reviews in order to lead the readers to earlier work often unavailable on the Internet. It is obvious now that in Chi a fluorescence measurements, we have come a long way since Kautsky’s discovery 73 years ago. Chi a fluorescence has provided new and important information on the composition of the pigment systems, excitation energy transfer, physical changes in pigment-protein complexes, primary photochemistry, kinetics and rates of electron transfer reactions in Photosystem II (PS II), the sites of various inhibitors, and activators, and of lesions in newly constructed mutants. The purpose of this chapter is not to present the current and updated information on Chi fluorescence, but to guide the readers to the outstanding chapters written by international experts in the field. (Photographs of these authors are also included here.)