Hypocotyl segments of flax seedlings germinated in vitro, were used to induce indirect somatic embryogenesis on solid medium. The composition and distribution of n-alkanes in flax tissues collected at different developmental stages were studied by GC and GC-MS. During induction and development of callus from hypocotyl tissues a decrease in the percentage of total lipids was observed. In all types of tissue sampled - hypocotyl segments used as primary explants, hypocotyl segments with differentiating calli at the cut ends, embryogenic and non-embryogenic calli and somatic embryos - a skewed-normal distribution of n-alkanes with a low mass range (C13-C21) were found. The highest content of n-alkanes occurred in the primary hypocotyl explants and in the early stages of callus development. Longer carbon chain n-alkanes were observed only in the mature or differentiated tissues of hypocotyls and somatic embryos. Although the n-alkane contents decreased with time, in somatic embryos and calli, a significantly lower n-alkane content was observed in embryogenic calli when compared to non-embryogenic calli independent of the time in culture. These results suggest the utilisation of n-alkanes for heterotrophic cellular growth as well as its mobilisation from embryogenic calli to developing somatic embryosJunta Nacional de Investigação Científica e Tecnológica (JNICT) - BD/2771/93
