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ABSORPTION, TRANSLOCATION AND METABOLISM OF CHLORSULFURON AND THE EFFECTS OF HERBICIDE - GROWTH REGULATOR COMBINATIONS ON CANADA THISTLE (CIRSIUM ARVENSE) CONTROL
Abstract
Foliar and nutrient solution treatments of ('14)C-chlorsulfuron {2-chloro-N-{{(4-methoxy-6-methyl-1,3,5-triazin-2-yl)amino}carbonyl}benzenesulfonamide} applied to hydroponically grown Canada thistle resulted in limited absorption and translocation 48 h after treatment. Absorption was 39% of ('14)C applied to the foliage and 16% when the ('14)C-chlorsulfuron was added to the nutrient solution. Only 10% of the foliar applied ('14)C applied moved out of the treated leaf. Similarly 10% moved from the roots to other parts of the plant. Metabolism of ('14)C-chlorsulfuron following foliar treatment was insignificant 48 h after treatment. However, when ('14)C-chlorsulfuron was applied via the nutrient solution nearly 25% of the ('14)C was present as polar product(s), 13% as the acid hydrolysis product benzenesulfonamide while 62% remained as the parent chemical chlorsulfuron. Chlorsulfuron was not metabolized in nutrient solution alone to a similar extent even after 4 days. Suppression of regrowth was the primary injury symptom observed following chlorsulfuron applications to soil grown plants. Chlorsulfuron also reduced the number of root buds, root shoot fresh weight and whole plant fresh weight of Canada thistle. Addition of the growth regulators ethephon {(2-chloroethyl) phosphonic acid} or chlorflurenol (methyl 2-chloro-9-hydroxyfluorene-9-carboxylate) to the herbicides chlorsulfuron, glyphosate {N-(phosphonomethyl)glycine} or dicamba (3,6-dichloro-o-anisic acid) in field trials failed to significantly enhance control of Canada thistle in the prebud, bud or fall rosette stage. Contrary to field results, greenhouse results showed chlorflurenol additions to dicamba or chlorsulfuron increased the suppression of Canada thistle regrowth over the herbicides used alone at the same rates. Canada thistle plants treated with chlorflurenol, then cut off at the soil line 48 h after treatment failed to produce more root shoots than untreated plants. These data fail to support the hypothesis that chlorflurenol enhances herbicidal efficacy of dicamba, glyphosate or chlorsulfuron by stimulating root bud activity of Canada thistle.
Subject Area
Agronomy
Recommended Citation
PETERSEN, PHIL J, "ABSORPTION, TRANSLOCATION AND METABOLISM OF CHLORSULFURON AND THE EFFECTS OF HERBICIDE - GROWTH REGULATOR COMBINATIONS ON CANADA THISTLE (CIRSIUM ARVENSE) CONTROL" (1983). ETD collection for University of Nebraska-Lincoln. AAI8404841.
https://digitalcommons.unl.edu/dissertations/AAI8404841