Essential protein that catalyzes the condensation reaction of fatty acid synthesis by the addition to an acyl acceptor of two carbons from malonyl-ACP. Specific for elongation from C-16 and C-16 to unsaturated C-18 fatty acids. Confers resistance to low temperatures by maintaining chloroplast membranes integrity. Involved in the regulation of fatty acids ratios during seed metabolism. Required for embryo development, especially at the transition from the globular to the heart stage