Date of Award

Summer 1980

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Biological Sciences

Program/Concentration

Biology

Committee Director

Kneeland K. Nesius

Committee Member

Frank P. Day, Jr.

Committee Member

Paul W. Kirk, Jr.

Call Number for Print

Special Collections LD4331.B46 E44

Abstract

An investigation of the effect of metolachlor, a chloracetamide herbicide released for agricultural purpose during the Spring of 1977, on plant tissue levels of phosphorus, potassium, calcium and magnesium in juvenile sweet corn and the recovery rate of sweet corn exposed to metolachlor from any plant nutrient effects when the herbicide was removed.

An increase of metolachlor concentration caused a progressive reduction in growth (height and dry weight) of the leafy portion of juvenile sweet corn. At metolachlor concentrations of 0.16 ppm and higher pronounced stunting and twisting were observed in the plants.

There was a progressive reduction in the total accumulation (expressed as milligrams) of phosphorus, potassium and calcium as the metolachlor concentrations increased. There was a progressive increase in the percentage of phosphorus and calcium in the leafy tissue as the herbicide concentrations increased. The level of potassium exhibited a progressive increase in some runs and a progressive reduction in other runs. Neither the accumulation nor the percentage in the tissue of magnesium was affected by the concentrations of metolachlor used.

Temperature, light intensity and/or day length also appear to have an affect on the response of sweet corn to metolachlor. In the runs conducted while these factors were most intense, disruption in growth and the levels of phosphorus, potassium and calcium (accumulation and the percentage in tissue) occurred at lower metolachlor concentrations.

Plants which were retained in the 0.80 ppm metolachlor solution showed a decrease in the accumulation (expressed as milligrams} of phosphorus, potassium and calcium. The percentage of calcium increased while that of phosphorus and potassium varied with the run. Plants which were removed after 72 hours of exposure to metolachlor and placed in an herbicide-free nutrient solution had phosphorus, calcium and potassium levels (percentage and milligrams of accumulation) similar to that of the controls.

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DOI

10.25777/6ka2-qe86

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