Ontogenic variations in n-alkanes during somatic embryogenesis of flax (Linum usitatissimum L.)

Hypocotyl segments (HS) of flax seedlings germinated in vitro, were used to induce indirect somatic embryogenesis on solid medium. The composition and distribution of il-alkanes in flax tissues collected at different developm ental stages were studied by capillary gas chromatography (GC) and capillar y gas chromatography-mass spectrometry (GC-MS). During induction and develo pment of callus from hypocotyl tissues a decrease in the percentage of tota l lipids was observed. In all types of tissue sampled - PIS 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-n ormal distribution of n-alkanes with a low mass range (C-13-C-21) were foun d. The highest content of n-alkanes occurred in the primary hypocotyl expla nts and in the early stages of callus development. Longer carbon chain n-al kanes were observed only in the mature or differentiated tissues of hypocot yls and SE. Although the n-alkane contents decreased with time, in SE and c alli, a significantly lower n-alkane content was observed in EC when compar ed to NEC independent of the time in culture. These results suggest the uti lisation of n-alkanes for heterotrophic cellular growth as well as its mobi lisation from EC to developing SE. (C) 2001 Elsevier Science Ireland Ltd. A ll rights reserved.