Lipid metabolism in oil palm (Elaeis guineensis and Elaeis oleifera) protoplasts

Abstract

Protoplasts were enzymatically prepared from the mesocarp of two species of oil palm (Elaeis guineensis Jacq. and E. oleifera HBK and Cortes) 16-20 weeks after anthesis and from rapidly multiplying embryogenic cultures of E. guineensis. The protoplasts were purified by density gradient centrifugation in 20% (w/v) sucrose. Radioactive incorporation studies showed that the protoplasts metabolized [1-14C]acetate to lipids, water-soluble compounds and 14CO2. The [14C]fatty acids obtained consisted mainly of C16: 0, C18: 0 and C18: 1. C16: 1, a very minor fatty acid in palm oil, was also labelled and accounted for 8-39% of total fatty acids synthesized by the mesocarp and embryogenic culture protoplasts. The ratio of labelled C18: 0 to C18: 1 was found to vary with the age of the fruit from which the protoplasts were prepared. Thin layer chromatography (TLC) of the labelled lipids showed the presence of all neutral acylglycerol classes. However the distribution of radiolabel in the various classes differed from those previously reported for oil palm mesocarp [K.C. Oo et al. Lipids, 20 (1985) 205] and embryoid tissue slices [E. Turnham and D.H. Northcote, Phytochem., 23 (1984) 35]. Ozonolysis showed that all the labelled C18: 1 acid was vaccenic acid. © 1987.