Effect of selenium on characteristics of rape chloroplasts modified by cadmium.
Selenium appears to be an important protective agent that decreases cadmium-induced toxic effects in animals and plants. The aim of these studies was to investigate the changes of properties of chloroplast membranes obtained from Cd-treated rape seedlings caused by Se additions. Chloroplasts were isolated from leaves of 3-week-old rape plants cultured on Murashige-Skoog media supplied with 2 microM Na(2)SeO(4) and/or 400 microM CdCl(2) under in vitro conditions. The following physicochemical characteristics of chloroplasts were chosen as indicators of Se-effects: average size, zeta potential, ultrastructure, lipid and fatty acid composition and fluidity of envelope membrane. The results suggest that Se can partly counterbalance the destructive effects of Cd. This protective action led to an increase of chloroplast size reduced by Cd treatment and rebuilt, to some extent, the chloroplast ultrastructure. Lipid and fatty acid composition of chloroplast envelopes modified by Cd showed a decrease in digalactosyl-diacylglycerol content and an increase of content of monogalactosyl-diacylglycerol and phospholipid fractions, as well as an increase of fatty acid saturation of all lipids studied. The change in fatty acid saturation correlated well with a decrease of membrane fluidity and with a diminishing of absolute values of zeta potential. The presence of selenium in cultured media caused a partial reversal of the detected changes, which was especially visible in properties related to the hydrophobic part of an envelope, i.e. fatty acid saturation and fluidity.
Filek
Maria
M
Institute of Plant Physiology, Polish Academy of Sciences, Podłuzna 3, 30-239 Kraków, Poland.
Gzyl-Malcher
Barbara
B
Zembala
Maria
M
Bednarska
Elzbieta
E
Laggner
Peter
P
Kriechbaum
Manfred
M
D029688:Brassica napus / Q000187:drug effects* / Q000254:growth & development / Q000502:physiology* / Q000648:ultrastructure; D002104:Cadmium / Q000633:toxicity*; D002736:Chloroplasts / Q000187:drug effects* / Q000502:physiology* / Q000648:ultrastructure; D003470:Culture Media / Q000494:pharmacology; D005227:Fatty Acids / Q000032:analysis; D005454:Fluorescence Polarization; D008027:Light; D053141:Organelle Size / Q000187:drug effects; D018515:Plant Leaves / Q000187:drug effects / Q000254:growth & development / Q000648:ultrastructure; D053838:Scattering, Small Angle; D012643:Selenium / Q000494:pharmacology*; D014961:X-Ray Diffraction
D003470:Culture Media; D005227:Fatty Acids; D002104:Cadmium; D012643:Selenium