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DISTORTION OF ACTION SPECTRA IN PHOTOMORPHOGENESIS BY LIGHT GRADIENTS WITHIN THE PLANT TISSUE
Author(s) -
KazarinovaFukshansky Nina,
Seyfried Max,
Schäfer Eberhard
Publication year - 1985
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.1985.tb03624.x
Subject(s) - pigment , phytochrome , action spectrum , photomorphogenesis , etiolation , far red , biophysics , optics , light scattering , chemistry , red light , materials science , botany , biology , physics , scattering , biochemistry , organic chemistry , arabidopsis , gene , mutant , enzyme
— Recently a method for measuring optical properties of light scattering and absorbing tissues was discussed (Seyfried et al., 1983). Based on measurements of transmittance and reflectance of cotyledons of dark‐ and light‐grown Cucurbita pepo L, seedlings a method to compute and correct apparent photoconversion cross sections for various distributions of a sensory pigment is described. The distortion function may be used to calculate expected apparent (distorted) action spectra for a pigment in vivo when the spectral properties of the pigment in vitro are known. With phytochrome as an example for a sensory pigment of low concentration within the tissue it is shown that the low apparent photoconversion cross section in blue light observed in etiolated seedlings can be explained solely by optical distortions caused by light gradients. In green tissue on the other hand the ratio of the apparent photo conversion cross sections in red and blue light is almost identical with that observed in vitro, but the ratio in red and far‐red light depends strongly on the distribution of the relevant sensory pigment. An analysis of the rate of phytochrome cycling shows an additional peak in the far‐red if the pigment is localized in the lower part of the tissue only.