Propagation of Mammillaria candida (Cactaceae) by tissue culture techniques

In vitro propagation Mammillaria candida was evaluated using different media containing several combinations of growth regulators. Seeds were germinated in full-strength Murashige-Skoog (MS), half-strength MS (1/2 MS) or in Schenk-Hildebrandt (SH) basal media. Plantlets. grown for 114 days in vitro, showed a higher increase in dry and fresh weight and in the length of their roots and shoots in MS medium compared to 1/2 MS and SH media. Epicotyls from these plantlets were used to induce shoot formation by placing them in MS medium containing benzyladenine (BA) at either 5 or 10 mg.l(-1), or kinetin (KIN) at 5 mg.l(-1), alone or in combination with 0.01 mg.l(-1) naphthalene acetic acid (NAA) and 1% activated charcoal. After GO days in culture, approximately eight shoots per explant were regenerated in medium containing 5 mg.l(-1) BA and 0.01 mg.l(-1) NAA, but callus and hyperhydricity (the formation of translucent tissue due to an excess of water) also developed. Well-defined shoots were obtained in the medium containing KIN. Root formation on these shoots was induced on MS and 1/2 MS media containing 3.24 mM CaCl2. A survival of 91% was achieved after transferring plants grown in vitro to soil. The results reported in this work suggest that M. candida can be propagated successfully using tissue culture techniques.