Plant Uptake and Growth Responses from p-Chlorophenyl Methyl Sulfide, -Sulfoxide, and -Sulfone in Soil1
- W. D. Guenzi,
- W. E. Beard,
- R. A. Bowman and
- S. R. Olsen2
A greenhouse experiment was conducted to determine the effects of three soil chemical concentrations of 14C-ring labeled p-chlorophenyl methyl sulfide, -sulfoxide, and -sulfone on seedling growth and uptake by alfalfa (Medicago sativa L.), corn (Zea mays L.), tall fescue (Festuca arundinacea Schreb.), sugarbeet (Beta vulgaris L.), and spring wheat (Triticum aestivum L.). Each crop was tested in separate experiments during a 3-month period in an Ascalon sandy loam (Aridic Argiustoll). Effects on growth were determined from plant height, dry matter production of roots and tops, and visual toxicity symptoms of leaves. Plant uptake of chemicals was evaluated from calculations using total 14C activity measurements of combusted plant samples. In most cases, there appeared to be little difference among the three chemicals. Reduction of root and top growth (dry weight) for each plant species was linearly related to increases in soil chemical concentrations. Growth reduction at a given chemical concentration varied among crop species, with alfalfa being the most susceptible and corn the least susceptible. The calculated mean soil concentrations of the three chemicals responsible for a 20% reduction in dry weight of tops were 4.7, 6.3, 7.3, and 15.5 ppm for alfalfa, rescue, sugarbeet, and wheat, respectively. The 20% reduction for corn was only obtained from the 2$-ppm sulfone treatment.
Chemical concentration in plant tissue increased almost linearly with increasing soil concentrations. The linear correlation coefficients were r = 0.894** (tops) and r = 0.942** (roots).Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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