Abstract
For dark-grown seedlings of Pharbitis nil capacity to flower in response to a single inductive dark period was established by 24 h white, far-red (FR) or ruby-red (BCJ) light and by a skeleton photoperiod of 10 min red (R)-24 h dark-10 min R. FR alone was ineffective without a brief terminal (R) irradiation, confirming that the form of phytochrome immediately prior to darkness is a crucial factor for flowering in Pharbitis. The magnitude of the flowering response was significantly greater after 24 h FR or white light (WL) (at 18° C and 27° C) than after two brief skeleton R irradiations, but the increased flowering response was not attributable to photosynthetic CO2 uptake because this could not be detected in seedlings exposed to 24 h WL at 18° C. Photophosphorylation could have contributed to the increased flowering response as photosystem I fluorescence was detectable in plants exposed to FR, BCJ, or WL, but there were large differences between flowering response and photosystem I capacity as indicated by fluorescence. We conclude that phytochrome plays a major role in photoresponses regulating flowering. There was no simple correlation between developmental changes, such as cotyledon expansion and chlorophyll formation during the 24-h irradiation period, and the capacity to flower in response to a following inductive dark period. Changes in plastid ultrastructure were considerable in light from fluorescent lamps and there was complete breakdown of the prolamellar body with or without lamellar stacking at 27 or 18° C, respectively, but plastid reorganization was minimal in FR-irradiated seedlings.
Similar content being viewed by others
Abbreviations
- BCJ:
-
irradiation from photographic ruby-red lamps
- FR:
-
far-red light
- Pfr :
-
far-red-absorbing from of phytochrome
- P:
-
total phytochrome content
- R:
-
red light
- WL:
-
white light from fluorescent lamps
References
Arnon, D.I.: Copper enzymes in isolated chloroplasts. Polyphenoloxidase in Beta vulgaris. Plant Physiol. 24, 1–15 (1949)
Boardman, N.K., Thorne, S.W., Anderson, J.M.: Fluorescence properties of particles obtained by digitonin fragmentation of spinach chloroplasts. Proc. Nat. Acad. Sci. USA 56, 586–593 (1966)
De Greef, J., Butler, W.L., Roth, T.F.: Greening of etiolated bean leaves in far red light. Plant Physiol. 42, 457–464 (1971)
Evans, L.T., King, R.W.: Role of phytochrome in photoperiodic induction of Pharbitis nil. Z. Pflanzenphysiol. 60, 277–288 (1969)
Fredericq, H.: Conditions determining effects of far-red and red irradiation on flowering response of Pharbitis nil. Plant Physiol. 39, 812–816 (1964)
Friend, D.J.C.: Light requirements for photoperiodic sensitivity in cotyledons of dark-grown Pharbitis nil. Physiol. Plant. 35, 286–296 (1975)
Henningsen, K.W., Thorne, S.W.: Esterification and spectral shifts of chlorophyllide in wild type and mutant seedlings developed in darkness. Physiol. Plant. 30, 82–89 (1974)
Jose, A.M., Vince-Prue, D.: Light-induced changes in the photoresponses of plant stems; the loss of a high irradiance response to far-red light. Planta 135, 95–100 (1977)
Jose, A.M., Vince-Prue, D.: Phytochrome action in green plants: a reappraisal. Photochem. Photobiol. 27, 209–216 (1978)
King, R.W.: Phytochrome action in the induction of flowering in short-day plants: effect of photoperiod quality. Aust. J. Plant Physiol. 1, 445–457 (1974)
King, R.W., Evans, L.T.: Timing of evocation and development of flowers in Pharbitis nil. Aust. J. biol. Sci. 22, 559–572 (1969)
King, R.W., Vince-Prue, D., Quail, P.H.: Light requirement, phytochrome and photoperiodic induction of flowering of Pharbitis nil Chois. III. A comparison of spectrophotometric and physiological assays of phytochrome transformation during induction. Planta 141, 15–22 (1978)
McWilliam, J.R., Naylor, A.W.: Temperature and plant adaptation. I. Interaction of temperature and light in the synthesis of chlorophyll in corn. Plant Physiol. 42, 1711–1715 (1967)
Marushige, K., Marushige, Y.: Photoperiodic sensitivity of Pharbitis nil seedlings of different ages in special reference to growth patterns. Bot. Mag. (Tokyo) 76, 92–99 (1963)
Marushige, K., Marushige, Y.: Effects of light on the appearance of photoperiodic sensitivity of etiolated Pharbitis nil seedlings. Bot. Mag. (Tokyo) 79, 397–403 (1966)
Miyoshi, Y., Furuya, M., Takimoto, A.: Dark transformations of phytochrome in cotyledons of Pharbitis nil. Plant Cell Physiol. 15, 1115–1123 (1974)
Mohr, H., Appuhn, V.: Die Keimung von Lactuca-Achänen unter dem Einfluß des Phytochromsystems und der Hochenergiereaktion der Photomorphogenese. Planta 60, 274–288 (1963)
Oelze-Karow, H., Butler, W.L.: The development of photophosphorylation and photosynthesis in greening bean leaves. Plant Physiol. 48, 621–625 (1971)
Schäfer, E.: A new approach to explain the “high irradiance responses” of photomorphogenesis on the basis of phytochrome. J. Math. Biol. 2, 41–56 (1975)
Tagawa, K., Tsujimoto, H.Y., Arnon, D.I.: Separation by monochromatic light of photosynthetic phosphorylation from oxygen evolution. Proc. Nat. Acad. Sci. USA 50, 544–549 (1963)
Venable, J.H., Coggeshall, R.: A simplified lead citrate stain for use in electron microscopy. J. Cell Biol. 25, 407–408 (1965)
Vince-Prue, D., King, R.W., Quail, P.H.: Light reqirement, phytochrome and photoperiodic induction of flowering of Pharbitis nil Chois. II. A critical examination of spectrophotometric assays of phytochrome transformations. Planta 141, 9–14 (1978)
Virgin, H.I.: Light-induced stomatal transpiration of etiolated wheat leaves as related to chlorophyll content. Physiol. Plant. 9, 482–493 (1956)
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
King, R.W., Vince-Prue, D. Light requirement, phytochrome and photoperiodic induction of flowering of Pharbitis nil Chois. Planta 141, 1–7 (1978). https://doi.org/10.1007/BF00387736
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00387736