DISTRIBUTION OF LIPID RADIOACTIVITY AFTER FRACTIONATION OF C-14-LABELED ZYGOTIC RAPE EMBRYOS

In developing green rape embryos isolated from oilseed rape (Brassica napus L. cv. Nilla) lipid synthesis from [C-14]bicarbonate, [1-C-14]ac etate and [U-C-14]glycerol was significantly driven by light. In contr ast to erucate-free varieties the embryos of this erucate-rich variety showed enhanced triacylglycerol formation, caused primarily by incorp oration of erucate into diacylglycerol. After fractionation of labelle d embryos the products of triacylglycerol formation with very long cha in fairy acids accumulated in the oil body-enriched fat pad. The low i ncorporation rates into very long chain fatty acids and triacylglycero ls remaining in the microsomal fraction correspond to elongation activ ities and triacylglycerol synthesizing capacities of microsomes in vit ro. Together with recent findings in other laboratories these results suggest an intimate association of oil bodies with domains of the endo plasmic reticulum, which are Involved in the synthesis of storage lipi ds.