Corn tolerance to atrazine and cadmium and sunflower to cadmium in soil and hydroponic culture
Hydroponic culture is often used for screening plant tolerance or remediation efficacy to environmental pollutants. Field experiments are usually avoided because of soil and groundwater contamination; thus pot experiments are the next step. In this study, the effect of various levels of atrazine in corn and cadmium (Cd) in corn and sunflower on physiological traits was comparatively investigated in hydroponic and soil culture. Also, Cd absorption and transfer factor to shoots were determined in soil.. Atrazine affected corn growth at about 20% at the rates of 2 mg L-1 and 20 mg kg(-1). In both species, Cd was largely stored in the root (75-88%), and the transfer factor was higher in corn than sunflower (0.59 vs. 0.37, at 20 mg kg(-1)). Cadmium threshold of 20% reduction in shoot growth, leaf area, and chlorophyll in corn was observed at about 20, 40, and 80 mg kg(-1), respectively. The ratio of hydroponic-soil pollutant rate that similarly affected plant growth was about 1:10 and 1:5 for atrazine and Cd, respectively. The linear correlation coefficient between traits was also studied.