Journal
PLANT CELL AND ENVIRONMENT
Volume 35, Issue 12, Pages 2075-2086Publisher
WILEY
DOI: 10.1111/j.1365-3040.2012.02537.x
Keywords
cadmium; carbon metabolism; cyanobacteria; excitation pressure; photosynthesis
Categories
Funding
- Hungarian Research Fund (OTKA) [CNK-8345, 68692]
- Social Renewal Operational Programme [TAMOP-4.2.2/B-10/1-2010-0012]
- Hungary-Romania Cross-Border Co-operation Programme [HURO/0901/270/2.2.2.]
Ask authors/readers for more resources
Despite intense research, the mechanism of Cd2+ toxicity on photosynthesis is still elusive because of the multiplicity of the inhibitory effects and different barriers in plants. The quick Cd2+ uptake in Synechocystis PCC 6803 permits the direct interaction of cadmium with the photosynthetic machinery and allows the distinction between primary and secondary effects. We show that the CO2-dependent electron transport is rapidly inhibited upon exposing the cells to 40 mu m Cd2+ (50% inhibition in similar to 15 min). However, during this time we observe only symptoms of photosystem I acceptor side limitation and a build of an excitation pressure on the reaction centres, as indicated by light-induced P700 redox transients, O-2 polarography and changes in chlorophyll a fluorescence parameters. Inhibitory effects on photosystem II electron transport and the degradation of the reaction centre protein D1 can only be observed after several hours, and only in the light, as revealed by chlorophyll a fluorescence transients, thermoluminescence and immunoblotting. Despite the marked differences in the manifestations of these short- and long-term effects, they exhibit virtually the same Cd2+ concentration dependence. These data strongly suggest a cascade mechanism of the toxic effect, with a primary effect in the dark reactions.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available