Effect of salt stress on fatty acid and α-tocopherol metabolism in two desert shrub species.

Abstract

Compared to Artemisia ordosiea Kraschen, a higher content of α-tocopherol in Artemisiasphaerocephala Kraschen under salt stress inhibits the conversion of linoleic acid (C18:2) into linolenic acid (C18:3), maintains cell membrane stability and contributes to higher salt resistance. Artemisia sphaerocephala Kraschen and Artemisia ordosiea Kraschen are widely distributed in the arid and semiarid desert regions of the northwest of China. Under salt stress, it has been known that α-tocopherol(α-T) improves membrane permeability and maintains Na+/K+ homeostasis; however, the function of α-T in regulating membrane components of fatty acids is unknown. In this study, 100-day-old plants of A. ordosiea and A. sphaerocephala are subjected to various NaCl treatments for 7, 14, and 21days. Compared to A. ordosiea, A. sphaerocephala has a higher Na+ concentration, higher chlorophyll content and dry weight in all NaCl treatments, but lower relative electric conductivity. The stable unsaturated levels of the lipids in A. sphaerocephala may be attributed to higher level of C18:2. Under 200mM NaCl treatment, α-T and C18:2 contents in A. sphaerocephala increase significantly, while the Na+, C18:1, C18:3 and jasmonic acid (JA) contents decrease. Moreover, α-T is positively correlated with C18:2, but negatively correlated with C18:3.