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Responsivity amplification by light in phytochrome‐mediated induction of chloroplast glyceraldehyde‐3‐phosphate dehydrogenase (NADP‐dependent, EC 1.2.1.13) in the shoot of milo ( Sorghum vulgare Pers.)
Author(s) -
OELMÜLLER RALF,
MOHR HANS
Publication year - 1984
Publication title -
plant, cell and environment
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.646
H-Index - 200
eISSN - 1365-3040
pISSN - 0140-7791
DOI - 10.1111/j.1365-3040.1984.tb01197.x
Subject(s) - phytochrome , responsivity , chloroplast , darkness , botany , glyceraldehyde 3 phosphate dehydrogenase , dehydrogenase , biology , glyceraldehyde , shoot , phototaxis , biophysics , chemistry , biochemistry , optics , red light , physics , enzyme , photodetector , gene
. A prolonged light treatment strongly increases responsivity to Pfr in many instances of phytochrome‐controlled biogenesis of flavone or cyanidin glycosides. The present investigation deals with the question of whether light also leads to a corresponding increase of responsivity towards Pfr in such photoresponses which are not related to synthesis of flavonoid pigments in outer tissue layers of seedlings. Phytochrome‐mediated accumulation of the chloroplast GPD (glyceraldehyde‐3‐phosphate dehydrogenase, EC 1.2.1.13) was chosen as a response and the milo shoot ( Sorghum vulgare Pers. cv. Weider, hybrid) as an appropriate subject. It was found that responsivity towards Pfr is extremely weak in a dark‐grown shoot while prolonged light pretreatments lead to a dramatic increase in responsivity. Blue and UV light are far more effective than red light in eliciting this effect within a few hours. High responsivity is only maintained in the light. When the seedlings are placed in darkness the level of responsivity drops rapidly with a half‐life of the order of 2 h. The data allow more complete explanations for intriguing phenomena of plant life under natural light/dark conditions such as shade detection or sensing of light → dark transitions.