Differential Effects of Cr(VI) on the Ultrastructure of Chloroplast and Plasma Membrane of Salvinia minima Growing in Summer and Winter. Relationships With Lipid Peroxidation, Electrolyte Leakage, Photosynthetic Pigments, and Carbohydrates

PRADO, CAROLINA; PRADO, FERNANDO E.; PAGANO, EDUARDO A.; ROSA, MARIANA

WATER AIR AND SOIL POLLUTION

SPRINGER

Lugar: Berlin; Año: 2015

0049-6979

Seasonal variations of chloroplast thylakoids and plasma membrane ultrastructure and changes in some biochemical parameters (e.g., metal accumulation, photosynthetic pigments, carbohydrates, lipid peroxida- tion, and electrolyte leakage) were studied in fronds of Salvinia minima plants exposed to increasing concen- trations of Cr(VI) in both winter and summer. Disorga- nization of stacked (grana) and unstacked (stroma la- mellae) thylakoids was greater in winter chloroplasts than in summer chloroplasts. Plasma membrane was less affected than thylakoids. Photosynthetic pigments, lipid peroxidation, soluble sugars, and starch were af- fected differently in winter and summer. Our results suggest that much greater ultrastructural alterations and changes in metabolite levels occurring in winter fronds are produced by higher oxidative stress resulting from the interactive effectbetween low temperature,low solar irradiance, and Cr(VI) toxicity, rather than from metal accumulation per se. Seasonal differences occurring in chloroplast ultrastructure and metabolite concentrations were discussed in relation to metabolic implications.