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ACTION SPECTRUM FOR ENHANCEMENT OF PHOTOTROPISM BY Arabidopsis thaliana SEEDLINGS
Author(s) -
Janoudi AbdulKader,
Poff Kfnneth L.
Publication year - 1992
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.1751-1097.1992.tb02218.x
Subject(s) - phototropism , action spectrum , fluence , irradiation , arabidopsis thaliana , phytochrome , wavelength , spectral line , biophysics , chemistry , photodissociation , botany , blue light , optics , physics , photochemistry , biology , mutant , red light , biochemistry , astronomy , nuclear physics , gene
— Fluence‐response relationships have been measured at wavelengths from 350 to 760 nm for the enhancement of phototropism in Arabidopsis thulium L . (Heynh) strain “Estland” by an irradiation at each of these wavelengths, given 2 h prior to a 450 nm inductive unilateral irradiation. Action spectra have been constructed from these fluence‐response relationships based on: (i) the fluence required to obtain a curvature of 25° (corresponding to an enhancement of 15°), (ii) the fluence required to obtain 50% of the maximum enhancement and (iii) the fluence threshold for enhancement by a pre‐irradiation. The action spectra exhibit two maxima, one at 669 nm and a second at 378 nm. The height of the maximum at 669 nm is approximately 4 times the height of the maximum at 378 nm. Based on the action spectra, it is concluded that the enhancement of phototropism in A. thaliana is mediated by phytochrome.