Spectral properties of a long-wavelength absorbing form of protochlorophyll in seeds of Cyclanthera explodens [seed coat, fluorescence spectra, circular dichroism spectra, protochlorophyll aggregates]
1980
Sundqvist, C. | Ryberg, H. | Boeddi, B. | Lang, F. (Goeteborg Univ. (Sweden). Dept. of Plant Physiology)
The in vivo absorbance spectrum of the inner seed coat of Cyclanthera explodens Naud. showed a main peak in the red region at 671 nm and a weak shoulder at about 640 nm. The pigments were extracted with acetone, separated by paper chromatography and analysed spectrophotometrically. The only detectable pigment was protochlorophyll. The in vivo fluorescence emission spectra had two main peaks, one at 632 and one at 691 nm. The relation between the two peaks was changed when the excitation wavelength was altered from 440 to 460 nm. Excitation at 420 nm gave an additional fluorescence emission peak at 595 nm. These data indicate the presence of at least three forms of protochlorophyll in the Cyclanthera seed coat. The spectrum of circular dichroism had a very intense and characteristic signal in the red region with a negative asymmetrical Cotton effect (664 (+), 669(0) and 687(-) nm). This indicates that at least one of the protochlorophyll forms is present in a more or less crystalline form
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