Changes in molecular species of triacylglycerols in developing cotton seeds under salt stress

Cotton plants (Gossypium hirsutum L. cv. S4) were grown and irrigated with increasing salt concentrations: 0, 50, 100 and 150 mM NaCl. Lipids from dev eloping seeds, at stages of 3, 4, 5 and 6 weeks after anthesis, were analys ed. High salt dose (150 mM NaCl) affected triacylglycerol levels drasticall y at the end of ripening. HPLC analysis of triacylglycerols in control seed s show-ed ten molecular species. Palmitodilinolein (PLL) is the major fract ion, representing about 25 % of total triacylglycerols. The levels of trili nolein (LLL), palmitolinoleo-olein (PLO) and oleodilinolein (OLL) molecules varied between 13 and 16% of the total. The other molecular species: triol ein (OOO), dioleopalmitin (POO) and dipalmitoolein (POP) are minds and do n ot exceed 5%. Moreover, the composition of triacylglycerol molecular specie s was almost constant during developing stages of control seeds. However, a mounts of triacylglycerol spec;es LLL, OLL and palmitodilinolein (PLL), as expressed on a dry-matter basis (mg/g), decreased severely under the highes t NaCl concentration, while contents of triacylglycerol species OOO, POO, P OP were unchanged. These findings confirm our previous results, which indic ated that the amount of linoleic acid in cotton seeds was reduced by salt s tress and that the amount of oleic acid remained unchanged.