Accumulation of lipids, proteins, alkaloids and anthocyanins during embryo development in vivo ofTheobroma cacao L.

Abstract

Developing embryos ofTheobroma cacao ranging in weight from 0.01–2.2 g dry weight, equivalent to 100–180 days postpollination, were analyzed for lipids, alkaloids, proteins, and anthocyanins. Total lipid, fatty acid, triglyceride, alkaloid, and anthocyanin accumulation increased linearly after an initial lag with embryo dry weight. Palmitic, stearic, arachidic, and oleic acids had constant rates of accumulation per micromole of total fatty acid (0.29, 0.27, 0.38, and 0.01, respectively); however, linoleic and linolenic acid accumulation decreased from 0.2 and 0.02 below 0.2 g dry weight to 0.035 and 0.0035 above 0.2 g dry weight, respectively. Monounsaturated triglycerides [palmito-oleo-stearin (POS), oleo-distearin (SOS), and oleo-dipalmitin (POP)] continued to accumulate as dry weight increased but polyunsaturated triglycerides [palmito-diolein (POO), stearo-diolein (SOO), linoleo-dipalmitin (PLP), and palmito-linoleo-olein (PLO)] ceased to accumulate at about 0.4 g dry weight. Theobromine accumulation increased linearly with dry weight after an initial lag but the rate differed with cultivar. Caffeine accumulation was low until the final stages of development. The protein pattern became dominated by 4 protein species with apparent molecular weights of 43, 34, 22, and 14 kDa as embryos matured.