OJIP CHLOROPHYLL A FLUORESCENCE MEASUREMENT TO ASSESS THE EFFECT OF PESTICIDE-COPPER MIXTURES ON DUCKWEED PHOTOSYNTHESIS

摘要

The substantial use of copper sulfate during the past hundred years as a fungicide increased the input of copper into the aquatic environment through surface water runoff. Since this heavy metal is often in contact with other pesticides, we investigated the effects of three herbicides (diuron, paraquat, fiazasulfuron) and copper alone and in combination on the photosynthetic apparatus of an aquatic plant, Lemna minor. These effects were determined by means of the Chl fluorescence transient O-J-I-P. Beside the results we demonstrated that Chl fluorescence analysis from polyphasic kinetics can be used as a useful physiological tool to assess early change in photosynthetic performance of Lemna minor in response to contaminant mixture pollutions.