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Phytochrome‐regulated Starch Degradation in Germinating Turions of Spirodela polyrhiza
Author(s) -
Dölger Korbinian,
Tirlapur Uday K.,
Appenroth KlausJ.
Publication year - 1997
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.1751-1097.1997.tb03148.x
Subject(s) - phytochrome , cycloheximide , starch , germination , botany , biology , abscisic acid , degradation (telecommunications) , biophysics , biochemistry , protein biosynthesis , red light , telecommunications , gene , computer science
— Turions of the duckweed Spirodela polyrhiza contain about 70% starch on the dry weight basis. The rate of starch degradation in nondormant turions was highest in continuous red light (cR) followed by continuous blue light (cB), whereas continuous far red light (cFR) is almost ineffective. Continuous R could be substituted by repeated R pulses; this effect was not photoreversible by FR pulses applied after hourly R pulses. This suggested that R‐dependent high irradiance response is the mode of phytochrome action in mediating starch degradation. Comparing the mode of phytochrome action with that of phytochrome mutants of other plants it can be assumed that phytochrome B is the photoreceptor involved. Application of the translation inhibitor cycloheximide immediately stopped the phytochrome‐dependent starch degradation demonstrating the involvement of de novo synthesis of proteins.