Changes in the composition of fatty acids and sterols of membrane lipids during induction and differentiation of Brassica napus (var. oleifera L.) callus

Changes in the membrane lipid and sterols content and composition were studied during induction and differentiation in callus cultures of Brassica napus var. oleifera. Callus induction was associated with an increase of DGDG content, significant changes in fatty acids composition of all lipid fractions and increased degree of lipid unsaturation. The membrane lipid composition of tissue at different degrees of differentiation was found to vary significantly, particularly two weeks after transfer of callus to regeneration medium. The main differences concerned the content and composition of galactolipids. Curiously in many cases, these differences declined during subsequent culture, in spite of the morphogenesis process which was in progress. Another result of differentiation was the change in free sterol composition: in shoot regenerating calli the content of stigmasterol had rose whereas the accumulation of campesterol decreased. Even though observed changes in membrane properties may not play a role in morphogenesis they are nevertheless useful as developmental markers and can be invaluable in understanding biochemical basis of morphogenesis.