Herbicide Resistant Weeds

Cross tolerance to herbicidal and environmental oxidants of plant biotypes tolerant to paraquat, sulfur dioxide, and ozone.

Shaaltiel, Y., A. Glazer, P. F. Bocion, and J. Gressel. 1988. Cross tolerance to herbicidal and environmental oxidants of plant biotypes tolerant to paraquat, sulfur dioxide, and ozone. Pesticide Biochemistry and Physiology. 31: 13-23.

A paraquat-resistant Conyza bonariensis biotype was tolerant to SO2, and atrazine, acifluorfen, and 2 experimental pyrimidinedione derivatives, herbicides that generate or induce the generation of oxidants in the light. Its resistance was between 1.5 and 10 times greater than that of the sensitive biotype. Two strains of Lolium perenne, one paraquat tolerant and one SO2 tolerant, were compared for their tolerances to paraquat. Both were at least 10 times more tolerant to paraquat than the sensitive strain. The paraquat- and SO2-tolerant Lolium strains both had 70% more superoxide dismutase and 20% more glutathione reductase than the sensitive strain. One of four ozone-tolerant Nicotiana tabacum cultivars was 16 times more tolerant to paraquat than the ozone-sensitive cultivar. The ozone-tolerant cultivar had 60% more of the 3 superoxide dismutase isoenzymes present than the sensitive biotype. These results suggest that tolerance in these cases is related to a general ability to more rapidly detoxify the generated oxygen species.