ABSTRACT
Action spectroscopy (Chapter 112) is primarily a crucial methodology for experimentally estimating the absorption spectra and, thus, the chemical nature, of the (sometimes unidentified) photoreceptor molecules
involved in various light-dependent chemical and biological reactions. Technically, the development and extensive collaborative use (Table 115.1) of the Okazaki Large Spectrograph (OLS),
at the National Institute for Basic Biology (NIBB), Okazaki, Japan, and of computerized video image analysis methods
are especially noteworthy. For a definition of and comprehensive information about the major categories of plant and microbial
photosensory processes, i.e., photomovement and photomorphogenesis, the reader is referred to the chapters in this volume (e.g., Chapters 120 to 124) and also to other textbooks.
