Micropropagation of Turbinicarpus valdezianus (Möeller) Glass & Foster (Cactaceae) an Endemic Cactus in Northern Mexico

Abstract

An in vitro clonal propagation protocol based on axillary bud development was generated for Turbinicarpus valdezianus. An efficient multiplication rate was obtained using either longitudinal or apical explants from in vitro germinated seedlings. The proliferation capacity of these explants was evaluated by testing the single and interaction effects of five concentrations of 6-furfurylaminopurine (KIN) (0.00, 2.32, 4.64, 9.28, and 18.56 µm) and three concentrations of α-naphthalenacetic acid (NAA) (0.00, 0.54, and 2.70 µm), using Murashige and Skoog (MS) as basal medium. Statistical analysis showed that the highest average shoot proliferation of T. valdezianus was recorded with 9.28 µm of KIN, producing 11.75 and 4.50 plantlets per initial explant, for apical and lateral explants, respectively. Addition of NAA to the medium had an inhibitory effect on shoot proliferation for both explant types. The developed shoots in 9.28 µm of KIN and plant growth regulator (PGR)-free treatments were used for a rooting subculture phase. These shoots were then transferred to PGR-free MS medium, resulting in statistically significant different rooting frequencies of 78% and 97%, respectively. When transplanted in soil, the rooted shoots showed an average survival rate of 90%, without any significant statistical differences between treatments. This propagation protocol has the capacity to produce near to 21 plantlets per seedling in 27 weeks, i.e., 11.78 and 9.00 plantlets per apical and lateral explants, respectively, without callus or adventitious shoot formation. These features made it highly attractive as an in vitro clonal propagation method for T. valdezianus plants and the later implementation of a rescue program for threatened wild populations of this cacti species.