title: Ontogenic variations in n-alkanes during somatic embryogenesis of flax (Linum usitatissimum L.).
abstract: Hypocotyl segments (HS) 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 capillary gas chromatography (GC) and capillary gas chromatography-mass spectrometry (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 - HS used as primary explants, HS with differentiating calli at the cut ends (HSC), embryogenic (EC) and non-embryogenic calli (NEC) and somatic embryos (SE) - a skewed-normal distribution of n-alkanes with a low mass range (C(13)-C(21)) 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 SE. Although the n-alkane contents decreased with time, in SE and calli, a significantly lower n-alkane content was observed in EC when compared to NEC independent of the time in culture. These results suggest the utilisation of n-alkanes for heterotrophic cellular growth as well as its mobilisation from EC to developing SE.
authors.affiliation: Department of Biology, University of Minho, Campus de Gualtar, 4700-320, Braga, Portugal
authors.forename: A C.
authors.initials: AC
authors.lastname: Cunha
authors.forename: M
authors.initials: M
authors.lastname: Fernandes-Ferreira