Date of Award

12-1980

Degree Name

Doctor of Philosophy

Department

Science Studies

First Advisor

Dr. Clarence J. Goodnight

Second Advisor

Dr. R. Charles Bowers

Third Advisor

Dr. William B. Harrison III

Fourth Advisor

Dr. George G. Mallinson

Abstract

The purpose of this study was to analyze selected growth parameters of hydroponically grown corn seedlings (Zea mays) in relation to the uptake of the heavy metals, lead and cadmium. The corn seedlings were treated with various concentrations of lead and cadmium at different levels of pH, and phosphate and ferric ion concentrations. Root and shoot lengths were measured before and after heavy metal treatment to determine the relative growth in the different treatment solutions. Wet and dry weights were also obtained. The plant material was digested with nitric and perchloric acids in preparation for analysis for heavy metal content by atomic absorption spectrophotometry.

The results of the study suggested that: (1) Only small amounts of lead and cadmium were translocated to the shoots in these hydroponically grown corn seedlings. (2) The level of pH was not consistently related to the uptake of lead and cadmium in these hydroponically grown corn seedlings. (3) The uptake of cadmium in both roots and shoots of these seedlings was higher when ferric ion was lacking in the substrate at lower cadmium concentrations. (4) When different varieties of corn seedlings were compared, the most cadmium-tolerant variety was found to have the highest cadmium uptake in the roots and the least translocation to the shoots. (5) The uptake of lead and cadmium in these seedlings was positively related to the concentration of the heavy metals in the substrate, but the relationship was not linear. (6) Over a 12 day treatment period, cadmium was found to accumulate at a faster rate in the roots than the root dry mass increased.

Comments

Fifth Advisor: Dr. Jack S. Wood

Access Setting

Dissertation-Open Access

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