Planta

, Volume 154, Issue 2, pp 150–155

Light-controlled inhibition of hypocotyl growth inSinapis alba L. seedlings

Fluence rate dependence of hourly light pulses and continuous irradiation

Authors

  • Brigitte Heim
    • Biologisches Institut II der Universität
  • Eberhard Schäfer
    • Biologisches Institut II der Universität
Article

DOI: 10.1007/BF00387909

Cite this article as:
Heim, B. & Schäfer, E. Planta (1982) 154: 150. doi:10.1007/BF00387909

Abstract

Fluence rate-response curves were determined for the inhibition of hypocotyl growth in 54 h old dark-grownSinapis alba L. seedlings by continuous or hourly 5 min red light irradiation (24 h). In both cases a fluence rate-dependence was observed. More than 90% of the continuous light effect could be substituted for by hourly light pulses if the total fluence of the two different light regimes was the same. Measurements of the far red absorbing form of phytochrome ([Pfr]) and [Pfr]/[P tot] (total phytochrome) showed a strong fluence rate-dependence under continuous and pulsed light which partially paralleled the fluence rate-response curves for the inhibition of the hypocotyl growth.

Key words

High irradiance response (HIR)Hypocotyl (growth)Photoequilibrium (phytochrome)PhytochromeSinapis

Abbreviations

R

red

HIR

high irradiance response

Prfr

phytochrome in its red, far-red absorbing form

[Ptot]=[Pr]+[Pfr]

ψλ=k1/(k1+k2): photoequilibrium of phytochrome at wavelength λ, wherebyk1,2 rate constants ofPrPfr,PfrPr photoconversion

Ψ

[Pfr]/[Ptot]

Copyright information

© Springer-Verlag 1982