ECOGEOGRAPHIC VARIATION IN SEED FATTY-ACIDS OF AUSTROCEDRUS-CHILENSIS

Seed megagametophyte fatty acids were analyzed for proportional compos ition in 104 trees from 13 natural populations of Austrocedrus chilens is in Andean Chile and Argentina, using gas-liquid chromatography. A t otal of 15 fatty acids were identified from their methyl esters by GC retention times and by mass spectroscopy and included, as major compou nds, oleic, linoleic, linolenic and cis-5,11,14,17-eicosatetraenoic ac ids. Multivariate analyses indicated a separation of xeric zone popula tions (mediterranean Chile and the Argentinean steppe ecotone) from me sic populations (Argentinean Lakes and southern range in Chilean rainf orest). These differences were associated with a greater abundance of C20 unsaturated acids in the mesic group. Differentiation among medite rranean Chilean populations was relatively high, perhaps as a result o f their disjunct distribution. There was no evidence for lower levels of within-population variation for these isolated northern populations .