Micropropagation and reintroduction of the endemic Mammillaria mathildae (Cactaceae) to its natural habitat

Abstract

A rapid shoot multiplication protocol was established for the endangered cactus Mammillaria mathildae to reintroduce it to its natural habitat. In vitro-germinated seedlings were used as the source of explants. Three explant sources (apical, lateral, and basal excised from in vitro-germinated seedlings) were tested. Shoot multiplication was induced in Murashige and Skoog (MS) medium supplemented with different 6-benzylaminopurine/indole-3-acetic acid (BA/IAA) combinations (0, 22.19, 44.39 and 0, 1.43,2.85, 5.71, respectively). Explants developed abundant callus in the presence of any BA/IAA concentration, whereas hormone-free media produced 0.59 ± 0.11 new shoots (with a 41% callus development) from basal explants. Apical and lateral explants produced 1.14 ± 0.07 and 4.09 ± 0.13 new shoots, respectively, without callus generation. Plantlets originating from lateral explants developed a vigorous rooting system after 2 months growing on MS medium supplemented with 30 g L-1 sucrose. Under greenhouse conditions, 98% of micropropagated M. mathildae survived. Plantlets were reintroduced in an experimental plot near to Juriquilla's wild population of M. mathildae; over 52% of the outplanted M. mathildae lot declined after 5 months. Water availability wasassociated with the decline of outplanted populations during the first month (43%).