US EPA

530218 

Journal Article 

The effect of cadmium ions on the growth rate of the freshwater macrophyte duckweed Lemna minor 

Uysal, Y; Taner, F 

2007 

Yes 

Ekoloji Dergisi
ISSN: 1300-1361 

16 

62 

9-15 

English 

In this study, the effect of Cd(II) on the growth rate of Lemna minor was investigated in an aqueous media with changing initial pH (4.5-8.0), temperature (15-35 degrees C) and Cd(II) concentration (0.05-20.0 ppm). The frond numbers were determined by time, and the kinetic model of plant growth was derived and fitted to the first order reaction kinetics. The reaction rate constants (k; d(-1)) were determined for all conditions. Experimental results showed that k decreased in the Cd(II) containing media according to control. But, plant growth was affected positively in 0.05 ppm. For example, k was found to be 0.194 d(-1) for 0.05 ppm at pH 5.0, but it was 0.160 d(-1) for the control. Additionally, k decreased significantly in lower pH values, but it increased especially in the pH 7.0-8.0 range. The maximum k was obtained at 25 degrees C for both Cd(II) containing media and control. When the temperature was increased, k started to decrease at the 25-30 degrees C range. For example, it was found 0.145 d(-1) for 0.1 ppm Cd(II) and 0.160 d(-1) for the control at 25 degrees C, but it decreased to 0.014 d(-1) for 0.1 ppm Cd(II), and 0.121 d(-1) for the control at 30 degrees C. The results showed that Cd(II) was very toxic for Lemna and reduced the growth rates. 

cadmium; duckweed; growth rate; heavy metal; Lemna; heavy-metals; toxicity; copper; plants; bioaccumulation; aequinoctialis; accumulation; elements; lead; l.