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The role of light reactions in the regulation of anthocyanin synthesis in Petunia corollas
Author(s) -
Weiss David,
Halevy Abraham H.
Publication year - 1991
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.1991.tb01724.x
Subject(s) - anthocyanin , dcmu , petunia , chloroplast , pigment , photosynthesis , chemistry , sucrose , chalcone isomerase , hill reaction , biochemistry , botany , biology , flavonoid , chalcone synthase , photosystem ii , antioxidant , organic chemistry , gene
The role of light reactions in anthocyanin synthesis was studied in both attached and detached corollas of Petunia hybrida (cv. Hit Parade Rosa), the latter grown in vitro in media containing 150 m M sucrose and 50 μ M gibberellic acid (GA). Light was essential for the synthesis of anthocyanin in detached corollas, whereas in intact corollas its effect was only to enhance anthocyanin synthesis. Continuous white light at a fluence rate of at least 20 μmol m −2 s −1 was needed for anthocyanin synthesis in detached corollas. Blue light was more effective than red or green, and far‐red was ineffective. Pigmentation of detached corollas exposed to light was inhibited by the photosynthetic inhibitor 3‐(4‐dichlorophenyl)‐1,1‐dimethylurea (DCMU). The chloroplast uncoupler NH 4 Cl did not affect anthocyanin synthesis, which was, however, inhibited by the blocking of ATP synthesis in both the chloroplast and the mitochondria by dicyclohexylcarbodiimide (DCCD). Sucrose uptake in vitro was inhibited by DCMU and by darkness, and was promoted equally by blue and red light. The activity of phenylalanine ammonialyase (EC 4.3.1.5) was inhibited in detached corollas grown in the dark or in the light in the presence of DCMU. The activity of chalcone isomerase (EC 5.5.1.6) was not affected by light. These findings suggest that at least two different light reactions are involved in the regulation of anthocyanin synthesis in petunia corollas, namely the high irradiance reaction (HIR) and photosynthesis.