Article

Planta

, Volume 180, Issue 2, pp 166-174

First online:

The ratio of variable to maximum chlorophyll fluorescence from photosystem II, measured in leaves at ambient temperature and at 77K, as an indicator of the photon yield of photosynthesis

  • William W. AdamsIIIAffiliated withInstitut für Botanik und Pharmazeutische Biologie der Universität Würzburg
  • , Barbara Demmig-AdamsAffiliated withInstitut für Botanik und Pharmazeutische Biologie der Universität Würzburg
  • , Klaus WinterAffiliated withInstitut für Botanik und Pharmazeutische Biologie der Universität Würzburg
  • , Ulrich SchreiberAffiliated withInstitut für Botanik und Pharmazeutische Biologie der Universität Würzburg

Rent the article at a discount

Rent now

* Final gross prices may vary according to local VAT.

Get Access

Abstract

The response of a number of species to high light levels was examined to determine whether chlorophyll fluorescence from photosystem (PS) II measured at ambient temperature could be used quantitatively to estimate the photon yield of O2 evolution. In many species, the ratio of the yield of the variable (FV) and the maximum chlorophyll fluorescence (FM) determined from leaves at ambient temperature matched that from leaves frozen to 77K when reductions in FV/FM and the photon yield resulted from exposure of leaves to high light levels under favorable temperatures and water status. Under conditions which were less favorable for photosynthesis, FV/FM at ambient temperature often matched the photon yield more closely than FV/FM measured at 77K. Exposure of leaves to high light levels in combination with water stress or chilling stress resulted in much greater reductions in the photon yield than in FV/FM (at both ambient temperature and 77K) measured in darkness, which would be expected if the site of inhibition was beyond PSII. Following chilling stress, FV/FM determined during measurement of the photon yield in the light was depressed to a degree more similar to that of the depression of photon yield, presumably as a result of regulation of PSII in response to greatly reduced electron flow.

Key words

Chilling stress Chlorophyll fluorescence (ambient and 77K) Light stress Photoinhibition of photosynthesis Photosynthesis (photoinhibition) Water stress