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Detection of triazine and urea herbicide residues by various characteristics of oat seedlings in bioassays
Author(s) -
MARRIAGE P. B.
Publication year - 1975
Publication title -
weed research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.693
H-Index - 74
eISSN - 1365-3180
pISSN - 0043-1737
DOI - 10.1111/j.1365-3180.1975.tb01321.x
Subject(s) - dry weight , shoot , chemistry , avena , atrazine , water content , bioassay , agronomy , horticulture , orchard , picloram , moisture , zoology , pesticide , biology , genetics , geotechnical engineering , organic chemistry , engineering
Summary Atrazine, simazine, diuron, and linuron applied to soil increased the percentage moisture of oat ( Avena sativa L.) shoots in bioassays at the lowest dose tested of 0·25 ppm. Further increases occurred up to 2 ppm but at higher concentrations the percentage moisture decreased. At all doses of each herbicide, shoot dry weight was decreased. In oats grown on soil collected from a peach orchard which had received repeated annual applications of these herbicides, the percentage moisture of the oat shoots was higher than the control value whenever the oat dry weight was decreased and provided a method of residue detection as sensitive as dry weight measurements. Treatment of oats by soil application of the above herbicides in bioassays also caused increases in the electrical conductivity of an aqueous extract of the oat shoots per mg of dry weight and this characteristic was slightly more sensitive than dry weight in detecting herbicides in orchard soil. The conductivity of the extract per mg of water in the shoots, however, only increased as percentage moisture decreased. The weight of neutral water‐soluble material in oat shoots decreased much more rapidly than dry weight in bioassays with standard herbicide concentrations. Determination of the weight of neutral water‐soluble material in oat plants grown on orchard soil samples indicated the presence of herbicide residues in 50% of the cases in which residues were not detectable by dry weight. The weight of neutral material as a percentage of dry weight was almost as sensitive. Chemical analysis of soil in which oat plants had a decreased level of neutral water‐soluble compounds indicated that this characteristic had a lower limit of detection for herbicide residues of approximately 0.10 ppm.