Characteristics of the Fatty Acid Composition of the Vacuolar Membrane Lipids Under the Conditions of Stress Induced by Copper Ions

The effect of different concentrations of copper ions (100 and 500 mu M) on the fatty acid composition of the vacuolar membrane lipids of beet root tissues ( Beta vulgaris L.) was studied. Exposure to 100 mu M copper led to an increase in the content of FAs by 57 mu g/mg of total lipids as compared to the control. Stearoyl desaturase (SDR) activity decreased from 0.87 in the control to 0.77 at 100 mu M copper. Exposure to 500 mu M copper caused an increase in the SDR activity up to 0.93, but the proportion of FAs decreased by 50 mu g/mg of total lipids compared with 100 mu M copper. In addition, there was an increase in the saturation of tonoplast lipids to 44 and 40% at 100 and 500 mu M Cu2+, respectively. The results suggest that FAs of tonoplast lipids are involved in the stress response mechanisms induced by excessive Cu2+ concentrations.