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ANALYSIS OF Pfr DESTRUCTION IN AMARANTHUS CAUDATUS L EVIDENCE FOR TWO POOLS OF PHYTOCHROME *
Author(s) -
Brockmann J.,
Schaufer E.
Publication year - 1982
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.1751-1097.1982.tb02608.x
Subject(s) - phytochrome , kinetics , pulse (music) , biophysics , chemistry , in vivo , red light , botany , biology , physics , optics , quantum mechanics , detector , microbiology and biotechnology
— Kinetics of the destruction of the far red absorbing form of phytochrome (P fr ), measured by in vivo spectroscopy, show two phases: after a saturating red light pulse, rapid first order decay results in the loss of most, but not all, of the detectable P rr ; decay of the rest is much slower. The concentration of the more stable P fr is positively correlated to the concentration of the total P fr established at time zero. The linear relationship between total and ‘stable’ P fr exludes the existence of a threshold level of P fr for fast destruction. Photoconversion of the P r (red absorbing form of phytochrome) present during the slow decay, by exposure to a second light pulse, is followed by fast destruction of most of the newly formed P, r , whereas some P fr formed by the first pulse still remains. The experiment suggests that not all P fr molecules are accessible to the same destruction mechanism, i.e. there are two populations of P fI .