Axillary shoots of cacao (Theobroma cacao L.), induced in vitro with cytokinins (BA or TDZ), elongated and produced leaves only in the presence of cotyledons and/or roots. Detached axillary shoots, which do not grow in `vitro under conventional tissue culture protocols, rooted with auxin and developed normally in vivo. Detached axillary shoots from cotyledonary nodes and single-node cuttings from mature plants were induced to elongate and produce normal leaves in the presence of 20,000 ppm CO2 and a photosynthetic photon flux density (PPFD) of 150 to 200 μmol·s-1·m-2. Subculture nodal cuttings continued to elongate and produce leaves under elevated CO2 and light levels, and some formed roots. Subculture of microcuttings under CO2 enrichment could be the basis for a rapid system of micropropagation for cacao. Chemical names used: N -(phenylmethyl) -1 H -purin-6-amine (BA); 1 H -indole-3-butyric `acid (IBA); α -naphthaleneacetic acid (NAA); thidiazuron (TDZ).
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