Endopolyploidy pattern and efficiency of photosynthetic electron transport in Kochia scoparia (L.) Schrad. biotypes resistant/sensitive to atrazine and/or ALS inhibitors
Abstract
DNA ploidy levels in cells of leaves and stems of Kochia scoparia (L.) Schrad plants showing different sensitivity to triazine herbicides and/or inhibitors of acetolactate synthase (ALS) were evaluated using flow cytometry together with the activities of Photosystems 1 and 2 in isolated leaf mesophyll chloroplasts. Only DNA-diploids were found but endopolyploidy (nuclei with 2C, 4C, 8C DNA contents) occured in the above-ground parts of plants.
The susceptible and resistant biotypes did not differ in their endopolyploidy profiles but biotype resistant to atrazine was characterized by lower activity of Photosystem 2. No relationship with the resistance of plants to atrazine or ALS inhibitors was discerned regarding the activity of Photosystem 1.