Establishment of suspension culture in Theobroma cacao and polyamines associated with cacao embryogenesis
The effect of the position of excised hypocotyl discs on somatic embryo induction in liquid culture was studied. Shaking culture seems to be a rapid way of cacao somatic embryo regeneration since more than 40 embryos can be produced within 6 weeks directly from 5 mm hypocotyl discs cut near the apex. The importance of the position of transverse section cell layer explants and their biochemical characteristics on the establishment of cacao embryogenic suspension culture was scrutinized and discussed. In order to further improve cacao in vitro culture change in endogenous polyamines during zygotic versus somatic embryogenesis in Theobroma cacao L was analysed. Spermidine was the main polyamine in cacao tissues. In their early stages of embryogenesis, zygotic embryos contained more polyamine than in later stages. At the early stages, the zygotic embryos also contained more polyamine than the endosperm. Similar results were observed during somatic embryogenesis. The potential of using spermidine for cacao in vitro culture medium improvement is discussed.
KeywordsZygotic and somatic embryogenesis Cacao Liquid culture Cell layer Polyamines
The study was supported by the Alexander von Humboldt Stiftung (www.humboldt-stiftung.de) via grant to Nicolas Niemenak (Grant No KAM/1115305). The authors express gratitude to Thomas Tumforde and Detlef Böhm for their assistance during experiments.
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