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Photoinhibition of photosynthesis in Lemna gibba as induced by the interaction between light and temperature. I. Photosynthesis in vivo
Author(s) -
Ögren Erling,
Öquist Gunnar,
Hällgren JanErlik
Publication year - 1984
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.1984.tb00368.x
Subject(s) - photoinhibition , lemna gibba , photosynthesis , photon flux , botany , biology , quantum yield , biophysics , chemistry , photosystem ii , ecology , fluorescence , photon , physics , optics , aquatic plant , macrophyte
The floating angiosperm Lemna gibba L. was exposed for 2 h to various combinations of photosynthetic photon flux densities and temperature. The extent of photoinhibition of photosynthesis was assayed by measuring the net CO 2 uptake before and after a photoinhibitory treatment, and the time course for photoinhibition was studied. It was found that the maximum quantum yield and the light‐saturated rate of CO 2 uptake were affected by the interaction between light and temperature during the photoinhibitory treatment. At a constant photon flux density of 650 μmol m −2 s −1 the extent of photoinhibition increased with decreasing temperature showing that even a chilling‐resistant plant like L. gibba is much more susceptible to photoinhibition at chilling temperatures. About 60% photoinhibition of the quantum yield for CO 2 uptake could be obtained either by a high photon flux density of 1 750 μmol m −2 s −1 and 25°C or by a moderate photon flux density of 650 μmol m −2 s −1 and 3°C. The time courses of recovery from 60% photoinhibition produced by either of these two treatments were similar, indicating that the nature of the photoinhibition was intrinsically similar. The extent of photoinhibition was related to the amount of light absorbed in excess to what could be handled by photosynthesis at that temperature. The vital importance of photosynthesis in alleviating photoinhibition is discussed.