Responses of the Fatty Acid Composition of Solanum lycopersicum Exposed toHeavy Metal Stres

Abstract

The accumulation of heavy metals in the agricultural environments causes the oxidative stress in leading physiological and biochemical alterations in the plants. Regulation of fatty acids is considered as an adaptive mechanism for plants exposed to oxidative damages. In the present study, we investigated the changes of fatty acid composition with GC in the leaves of tomato subjected to increasing doses of heavy metals. The exposures of heavy metals changed the fatty acid compositions and ?-linoleic acid, palmitic acid and linoleic acid were the main fatty acids in respect to percentage, respectively. The percentages of arachidic acid, behenic acid, lignoceric acid and docosahexaenoic acid clearly increased in leaves of tomato. The level of linoleic acid and palmitoleic acid significantly reduced in all application of heavy metals compared to control plants. The content of stearic acid and oleic acid methyl ester changed depending on heavy metal types and doses while the quantity of ?-linolenic acid and palmitic acid remained unchanged by the treatment of Cu and Pb, but the application of Cd slightly increased the percentage of ?-linolenic acid in tomato leaves. The content of lipid peroxidation significantly increased in all exposures of heavy metal. The exposures of heavy metal increased the content of saturated fatty acid like arachidic acid, behenic acid and lignoceric acid, while heavy metals decreased linoleic acid and palmitoleic acid which belong to unsaturated fatty acid compared to control plants. These changes in the fatty acid percentages may be related to the increases of lipid peroxidation.