FLUORESCENCE EMISSION SPECTRA OF PARAQUAT RESISTANT CONYZA CANADENSIS DURING THE CHLOROPHYLL FLUORESCENCE INDUCTION AS DETERMINED BY THE CCD-OMA SYSTEM

摘要

A multichannel chlorophyll spectrofluorometer based on a charge coupled device (CCD-OMA fluorosensor) was used for fast screening of the chlorophyll fluorescence characteristics of paraquat sensitive (S) and paraquat resistant (PqR) horseweed (Conyza canadensis) biotypes. It is demonstrated that S and PqR plants can easily be distinguished already from some leaf samples by only one series of fluorescence spectra measurements. The chlorophyll fluorescence parameters Fm, Fs, and the chlorophyll fluorescence ratios Rfd and F690/735, calculated from the spectra taken at different times during the fluorescence induction kinetics, clearly indicate the different paraquat sensitivity of the two horseweed biotypes. With the fluorosensor it was also shown that the paraquat resistant planes were, however, sensitive to the herbicide diuron. The results are in good agreement with earlier results achieved by more sophisticated and time consuming methods.