Kurtyka Renata, Burdach Zbigniew, Karcz Waldemar
Department of Plant Physiology, Faculty of Biology and Environmental Protection, University of Silesia, ul. Jagiellońska 28, 40 032 Katowice, Poland.
Gen Physiol Biophys. 2011 Mar;30(1):52-8. doi: 10.4149/gpb_2011_01_52.
The effects of Cd and Pb on membrane potential (E(m)) and photoelectric reaction of Nitellopsis obtusa cells were investigated. It was found that Cd and Pb at 1.0 mM caused a depolarization of the E(m), whereas both metals at lower concentrations changed the E(m) in a different way. Pb at 0.1 mM and 0.01 mM hyperpolarized the E(m), whereas Cd at the same concentrations depolarized and did not change the E(m), respectively. In the presence of 0.01 mM Pb, the light-induced hyperpolarization of the E(m) was by 18% higher as compared to the control, whereas at 1.0 mM Pb it was by 40% lower. Pb at 0.1 mM and Cd at 0.01 mM or 5 × 0.01 mM did not change the light-induced membrane hyperpolarization. However, in the presence of Cd at 0.1 mM and 1.0 mM this hyperpolarization was 2-fold lower or was completely abolished, respectively. These results suggest that at high Cd and Pb concentrations both depolarization of the E(m) and decrease of light-induced membrane hyperpolarization in Nitellopsis obtusa cells are probably due to inhibition of the plasma membrane H(+)-ATPase activity, whereas both metals at lower concentrations differ in mechanism of membrane potential changes.
研究了镉（Cd）和铅（Pb）对钝节拟丽藻细胞的膜电位（E(m)）和光电反应的影响。结果发现，1.0 mM的Cd和Pb会导致E(m)去极化，而较低浓度的这两种金属则以不同方式改变E(m)。0.1 mM和0.01 mM的Pb会使E(m)超极化，而相同浓度的Cd分别使E(m)去极化和不改变E(m)。在存在0.01 mM Pb的情况下，与对照相比，光诱导的E(m)超极化高出18%，而在1.0 mM Pb时则低40%。0.1 mM的Pb以及0.01 mM或5×0.01 mM的Cd不会改变光诱导的膜超极化。然而，在存在0.1 mM和1.0 mM Cd的情况下，这种超极化分别降低了2倍或完全消失。这些结果表明，在高浓度的Cd和Pb下，钝节拟丽藻细胞中E(m)的去极化和光诱导的膜超极化的降低可能是由于质膜H(+)-ATPase活性受到抑制，而较低浓度的这两种金属在膜电位变化机制上有所不同。
