IDENTIFICATION OF 4 UNIVERSAL PROTOCHLOROPHYLLIDE FORMS IN DARK-GROWNLEAVES BY ANALYSES OF THE 77-K FLUORESCENCE EMISSION-SPECTRA

Low-temperature (77 K) fluorescence emission spectra of dark-grown lea ves from 12 different plant species were measured, corrected and analy sed at different stages of development. The second and fourth derivati ve of the spectra indicated the peak positions of possible spectral ba nds, which were used for resolution of the fluorescence spectra into g aussian components. Based on the intensities of the gaussian component s, statistical analyses were performed to determine a possible connect ion between the main peaks and their respective long-wavelength vibrat ional sublevels. Four universal protochlorophyll(ide) forms were disti nguished, with the main emission bands (half-bandwidths parentheses) a t 633 (14.5), 645 (14.3), 657 (10.5) and 670 (20.1) nm respectively. T heir vibrational sublevels were found at 693 (20.8), 710 (17.3), 726 ( 17.7) and 740 (21.0) nm respectively. The spectral characteristics of the different protochlorophyll(ide) forms are discussed in relation to their possible molecular structures and interactions with the surroun ding membrane components.