Fatty acid composition of mitochondrial membrane lipids in cultivated (Zea mays) and wild (Elymus sibiricus) grasses

The fatty acid composition of mitochondrial membrane lipids from seedlings of two grass species differing in their chilling tolerance, elymus (Elymus sibiricus) and maize (Zea mays), was studied by gas-liquid chromatography. An increased chilling tolerance of elymus, a perennial wild species, seems to be caused by a high content of unsaturated fatty acid residues in the total membrane lipids; linoleic (41.9%) and alpha-linolenic (23.4%) acids predominated among these fatty acids. The contents of linoleic and alpha-linolenic acids in the total lipids of maize membranes were 57.5% and 5.8%, respectively. Polar lipids of elymus mitochondrial membranes were characterized by about similar contents of linoleic (33.6%) and alpha-Linolenic (31.3%) acids. Linoleic acid (51.7%) predominated in maize mitochondrial polar lipids, whereas the alpha-linolenic acid content was 9.0%. A high level of omega3-desaturase activity in the mitochondrial membranes seems to be an important factor of elymus chilling tolerance. This high activity seems to be developed as an adaptation in the course of evolution of this species.