Abstract
The biological activity of the plant photochromic photoreceptor, phytochrome, is generally thought to reside in Pfr the far-red-absorbing form, whilst the red-absorbing Pr is inactive. This view is based solely on incomplete correlations between spectrophotometrically detectable Pfr and responses in etiolated tissues given brief light treatments1,2. Studies of light-grown seedlings have recently revealed an inverse, linear relationship between phytochrome-regulated extension growth and phytochrome photoequilibrium (defined as Pfr/(Pr+Pfr) and estimated from the spectral photon distribution of the actinic radiation)3–10. Such a relationship could only fit the ‘Pfr as active form’ theory if Pr+Pfr (that is, Ptotal) remained constant and independent of the light sources used. Here I report data from herbicide-bleached, light-grown maize seedlings which show that Ptotal is strongly dependent on the wavelength distribution of the radiation and that the amount of Pfr does not correlate with growth response.
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References
Oelze-Karow, H. & Mohr, H. Photochem. Photobiol. 18, 319–330 (1973).
Drumm, H. & Mohr, H. Photochem. Photobiol. 20, 151–157 (1974).
Holmes, M. G. & Smith, H. Nature 254, 512–514 (1975).
Holmes, M. G. & Smith, H. Photochem. Photobiol. 25, 551–557 (1977).
McLaren, J. S. & Smith, H. Pl. Cell Envir. 1, 61–67 (1978).
Morgan, D. C. & Smith, H. Nature 262, 210–212 (1976).
Morgan, D. C. & Smith, H. Planta 142, 187–193 (1978).
Morgan, D. C. & Smith, H. Planta 145, 253–258 (1979).
Morgan, D. C., O'Brien, T. & Smith, H. Planta 150, 95–196 (1980).
Smith, H. & Holmes, M. G. Photochem. Photobiol. 25, 547–550 (1977).
Hilton, J. L., Scharen, A. L., St. John, J. B., Moreland, D. E. & Norris, K. H. Weed Sci. 17, 541–547 (1969).
Jabben, M. & Deitzer, G. F. Photochem. Photobiol. 27, 799–802 (1978).
Jabben, M. & Deitzer, G. F. Pl. Physiol. 63, 481–485 (1979).
Jabben, M. Planta 149, 91–96 (1980).
Heathcote, L., Bambridge, K. R. & McLaren, J. S. J. exp. Bot. 30, 347–353 (1969).
Schäfer, E. J. math. Biol. 2, 41–56 (1975).
Gorton, H. L. & Briggs, W. R. Pl. Physiol. 66, 1024–1026 (1980).
Johnson, C. B. & Tasker, R. Pl. Cell Envir. 2, 259–268 (1979).
Pratt, L. H. Photochem. Photobiol. 27, 81–105 (1978).
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Smith, H. Evidence that Pfr is not the active form of phytochrome in light-grown maize. Nature 293, 163–165 (1981). https://doi.org/10.1038/293163a0
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DOI: https://doi.org/10.1038/293163a0
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