Abstract
Phytochrome was studied spectrophotometrically in Avena sativa L. seedlings that had been grown for 6 d in continous white fluorescent light from lamps. Greening was prevented through the use of the herbicide San 9789. When placed in the light, phytochrome (Ptot) decreased with first order kinetics (τ1/2 ≈ 2 h) but reached a stable low level (≈2.5% of the dark level) after 36 h. This concentration of phytochrome remained constant in the light and during the initial hours of a subsequent dark period, but increased significantly after a prolonged dark period. Evidence suggests that the constant pool of phytochrome in the light is achieved through an equilibrium between synthesis of the red absorbing (Pr) and destruction of the far-red absorbing form (Pfr) of phytochrome. It is concluded that the phytochrome system in light-grown oat seedlings is qualitatively the same as that known from etiolated monocotyledonous seedlings, but different than that described for cauliflower florets.
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Abbreviations
- Pfr :
-
the far-red light absorbing form of phytochroma
- Pr :
-
the red light absorbing form of phytochrome
- Ptot :
-
Pr+Pfr
- ks :
-
rate constant of Pr synthesis
- kd :
-
rate constant of Pfr destruction
- MOPS:
-
N-morpholino-3-propane-sulfonic acid
- IRIS:
-
Tris (hydroxymethyl) amino methane
- San 9789:
-
4-chloro-5-(methyl amino)-2-(α,α,α-trifluoro-m-tolyl)-3(2H)pyridazinone
References
Bartels, P.G., McCullough, C.: A new inhibitor of carotenoid synthesis in higher plants: 4-chloro-5-(dimethylamino)-2-α,α,α, (trifluoro-m-tolyl)-3(2H) pyridazinone (Sandoz 6706). Biochem. Biophys. Res. Commun. 48, 16–22 (1972)
Butler, W.L.: Effects of red and far-red light on the fluorescence yield of chlorophyll in vivo. Biochim. Biophys. Acta 64, 309–317 (1962)
Butler, W.L., Lane, H.G., Siegelman, H.W.: Non-photochemical transformations of phytochrome in vivo. Plant Physiol. 38, 514–519 (1963)
Clarkson, D.T., Hillman, W.S.: Stable concentrations of phytochrome in Pisum under continuous illumination with red light. Plant Physiol. 43, 88–92 (1968)
Gardner, G., Briggs, W.R.: Some properties of phototransformation of rye phytochrome in vitro. Photochem. Photobiol. 19, 367–377 (1974)
Hayes, R.G., Klein, W.H.: Spectral quality influences of light during development of Arabidopsis thaliana plants in regulating seed germination. Plant Cell Physiol. 15, 643–653 (1974)
Hilton, J.L., Scharen, A.L., St. John, J.B., Moreland, D.E., Norris, K.H.: Modes of action of pyridazinone herbicides. Weed Sci. 17, 541–547 (1969)
Jabben, M., Deitzer, G.F.: A method for measuring phytochrome in plants grown in white light. Photochem. Photobiol. 27, 799–802 (1978a)
Jabben, M., Deitzer, G.F.: Effects of the herbicide San 9789 on photomorphogenic responses. Plant Physiol., in press
Jose, A.M., Vince-Prue, D., Hilton, J.R.: Chlorophyll interference with phytochrome measurement. Planta 135, 119–123 (1977)
Lane, H.C., Siegelman, H.W., Butler, W.L., Firer, E.M.: Detection of phytochrome in green plants. Plant Physiol. 35, 414–416 (1963)
Pratt, L.H.: Molecular properties of phytochrome. Photochem. Photobiol. 27, 81–105 (1978)
Schäfer, E., Marchall, B., Marmé, D.: In vivo measurements of the phytochrome photostationary state in far-red light. Photochem. Photobiol. 15, 457–464 (1972)
Schäfer, E.: Variation in the rates of synthesis and degradation of phytochrome in cotyledons of Cucurbita pepo L. during seedling development. Photochem. Photobiol. 27, 775–780 (1978)
Withrow, R.B.: An interference filter monochromator system for the irradiation of biological material. Plant Physiol 32, 355–360 (1957)
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Jabben, M., Deitzer, G.F. Spectrophotometric phytochrome measurements in light-grown Avena sativa L.. Planta 143, 309–313 (1978). https://doi.org/10.1007/BF00392003
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DOI: https://doi.org/10.1007/BF00392003