Fatty acid patterns of neutral lipids from seeds, leaves and cell suspension cultures of Euphorbia characias

Photoautotrophic, photomixotrophic and heterotrophic cell suspension cultures of Euphorbia characias were analysed for fatty acid composition of their neutral lipids. Contents in exponential and stationary phases of growth were compared to those of seeds, leaves and calli from which cell suspensions were derived. Quantitatively, on a dry weight basis, neutral lipid amounts varied in the different cells from 15 to 40% of that in the leaves (5.14 mg per g dry wt) but they were very low compared to that in the seeds (330 mg per g dry wt). The highest values were observed during the exponential phase of growth with photosynthetic cell suspensions. Qualitatively, fatty acid distribution was similar in photoautotrophic cell suspensions and leaves with a high content of linolenic acid. The linolenic acid/linoleic acid ratio decreased from photoautotrophic to heterotrophic cell suspensions. In seeds, the maximal amount of linoleic acid is reached while linolenic acid almost disappears. The desaturation of C18 fatty acids is closely linked with the development of the photosynthetic apparatus and with a low growth rate.