Phytochrome in Pharbitis nil during and after de-etiolation |
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Authors: | J. Rombach J. Bensink N. Katsura |
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Affiliation: | Lab. of Plant Physiological Research, Gen. Foulkesweg 72, 6703 BW Wageningen, The Netherlands;National Inst. of Agricultural Sciences, Dept. of Physiology and Genetics, Yatabe, Tsukuba 305, Japan. |
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Abstract: | Phytochrome (P) was measured by in vivo spectrophotometry in the cotyledons of Pharbitis nil Choisy cv. Violet. In etiolated plants exposure to red light (R) results in a rapid fall in P content by destruction of the far-red absorbing form of phytochrome (Pfr). In continuous R or white light the P content falls as a result of destruction to a stable 3% of that originally present. In Norflurazon-treated white light de-etiolated plants, Pfr undergoes reversion in darkness to the red absorbing form of phytochrome (Pr) with a half life of 4 h at 19°C, while total P remains constant. Synthesis of Pr after de-etiolation occurs at a slow rate and is enhanced by terminating the de-etiolation light treatment with far-red light. The results are discussed in relation to the P control of flowering. |
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Keywords: | Age (physiological-) flower induction Norflurazon phytochrome Pfr-dark-reversion phytochrome pools |
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