Pawlik B, Skowronski T, Ramazanow Z, Gardestrom P, Samuelsson G
Ph-Dependent Cadmium Transport Inhibits Photosynthesis in the Cyanobacterium Synechocystis-Aquatilis
Environmental and Experimental Botany: 1993 33:331-337
Short-term (5-120 sec) transport of cadmium (Cd-109) into cells of the unicellular cyanobacterium Synechocystis aquatilis was studied using a rapid filtration technique. The transport was strongly pH-dependent, occurring at pH 7, but not at pH 5.5, and was also observed in long-term (40 min) experiments. For this process the optimum pH was approximately 7.5, uptake was considerably reduced at lower pHs. The entrance of cadmium disturbed photosynthetic activity and related processes. At pH 7, cadmium (8.9 muM) decreased CO2 fixation by about 55%, inhibited carbonic anhydrase activity (completely in intact cells, by 65%, in cell-free extracts) and photosynthetic O2-evolution by about 50%. At pH 5.5 no effects were observed.
e-link to journal