Effect of cadmium ions on the photoelectric potential of Zea mays L. plants

The relationship between the photoelectric reaction of Zea mays L. plants and concentrations of cadmium (10-2 M - 10-6 M) in the external medium was investigated. The experiments were carried out by using the conventional electrophysiological technique. The effect of cadmium ions on the acidification of the external medium by fragments of leaves has also been studied. Our results suggest that the photoelectric reaction in plants treated with cadmium ions was significantly reduced. The effect of cadmium ions on the photoelectric reaction at low concentrations (10-6 M, 10-5 M and 10-4 M) was mainly quantitative. High sublethal concentrations of this metal (10-3 M and 10-2 M) induced strong inhibition on these reactions. Measurements of pH of the incubation medium showed that cadmium-dec - reased light induced acidification by Zea mays L. leave cells and that the H+ electrogenic proton pump probably participated in generation of the photoelectric response in the green plant cells. Moreover, the correlation between the electric potential value and decrease in chlorophyll content in mesophyll cells was studied.