• Browse
    • Author
    • Year
    • Platform
    • Organizations
    • Programs
    • Research Networks
    • Type
  • Search
    • Simple
    • Advanced
  • About
    • About
    • Policies
    • Citation Guide
  • Login
    Logo Alfred Wegener Institut
    Logo Alfred Wegener Institut
    Alfred-Wegener-Institut
    Helmholtz-Zentrum für Polar-
    und Meeresforschung
    • Imprint
    • Contact
    • OAI
    • RSS 2.0

    EPIC.awi.de

    Home
    • Browse
      • Author
      • Year
      • Platform
      • Organizations
      • Programs
      • Research Networks
      • Type
    • Search
      • Simple
      • Advanced
    • About
      • About
      • Policies
      • Citation Guide
    • Login
      Login

      Circadian growth in Porphyra umbilicalis (Rhodophyta): spectral sensitivity of the circadian system

      Edit Item Edit Item

      General Information:

      Citation:
      Lüning, K. (2001): Circadian growth in Porphyra umbilicalis (Rhodophyta): spectral sensitivity of the circadian system , Journal of Phycology, 37 , pp. 52-58 .
      Cite this page as:
      hdl:10013/epic.14615
      Contact Email:
      kluening@awi-bremerhaven.de
      Related Data:

      Abstract:

      The circadian rhythm in growth of the red macroalga Porphyra umbilicalis was investigated under different spectral light conditions in laboratory-grown thalli. A free-running rhythm was observed in constant green or red light at irradiances of 2.5 to 20 µmol m-2s-1, while arhythmicity occurred in constant blue light at 6-20 µmol m-2s-1. The circadian oscillator controlling growth rhythmicity in Porphyra uses most of the visible sunlight spectrum and possibly multiple photoreceptors with a high sensitivity for blue and a lower sensitivity for red light. This was inferred from three experimental results. (a) The free-running period, t, of the growth rhythm decreased with increasing irradiance, from approximately 25 h at 2.5 µmol m-2s-1 to 22 h at 20 µmol m-2s-1 in both red or green light. (b) Dark pulses of 3 h duration interrupting otherwise continuous green or red light caused advances during the subjective day and delays during the subjective night so that the circadian oscillator in Porphyra is able to discriminate darkness from green or red light. (c) Low-irradiance blue light pulses (2.5 µmol m-2s-1) shifted the growth rhythm in red light of higher irradiance (e.g., 10 µmol m-2s-1), and a strong, high amplitude, type 0 phase response curve was obtained that is usually observed with light pulses shifting a circadian rhythm in otherwise continuous darkness.

      Further Details:

      Item Type:
      Article
      Authors:
      Lüning, K.
      Divisions:
      AWI Organizations > Biosciences > Coastal Ecology
      AWI Organizations > Biosciences > Integrative Ecophysiology
      Programs:
      Basic Research > Helmholtz Independent Research
      Eprint ID:
      4037
      Logo Alfred Wegener Institut
      Alfred-Wegener-Institut
      Helmholtz-Zentrum für Polar-
      und Meeresforschung
      Logo Helmholtz

      • Browse
        • Author
        • Year
        • Platform
        • Organizations
        • Programs
        • Research Networks
        • Type
      • Search
        • Simple
        • Advanced
      • About
        • About
        • Policies
        • Citation Guide
      • Imprint
      • Contact
      • OAI
      © Alfred-Wegener-Institut