Ecogeographic variation in seed fatty acids of Austrocedrus chilensis

Seed megagametophyte fatty acids were analyzed for proportional composition in 104 trees from 13 natural populations of Austrocedrus chilensis in Andean Chile and Argentina, using gas-liquid chromatography. A total of 15 fatty acids were identified from their methyl esters by GC retention times and by mass spectroscopy and included, as major compounds, oleic, linoleic, linolenic and cis-5,11,14,17-eicosatetraenoic acids. Multivariate analyses indicated a separation of xeric zone populations (mediterranean Chile and the Argentinean steppe ecotone) from mesic populations (Argentinean Lakes and southern range in Chilean rainforest). These differences were associated with a greater abundance of C20 unsaturated rated acids in the mesic group. Differentiation among mediterranean Chilean populations was relatively high, perhaps as a result of their disjunct distribution. There was no evidence for lower levels of within-population variation for these isolated northern populations.