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

Abstract

<jats:p>An in vitro clonal propagation protocol based on axillary bud development was generated for <jats:italic>Turbinicarpus valdezianus</jats:italic>. 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 µ<jats:sc>m</jats:sc>) and three concentrations of α-naphthalenacetic acid (NAA) (0.00, 0.54, and 2.70 µ<jats:sc>m</jats:sc>), using Murashige and Skoog (MS) as basal medium. Statistical analysis showed that the highest average shoot proliferation of <jats:italic>T. valdezianus</jats:italic> was recorded with 9.28 µ<jats:sc>m</jats:sc> 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 µ<jats:sc>m</jats:sc> 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 <jats:italic>T. valdezianus</jats:italic> plants and the later implementation of a rescue program for threatened wild populations of this cacti species.</jats:p>

Genetic evidence of multiple reproductive strategies in a microendemic and threatened cactus (Cactaceae: Discocactus Pfeiff) in Bahia, Brazil

“…Furthermore, it is important to create complementary initiatives, such as ex situ conservation (MMA 1992), considering their viability and simplicity to maintain a species (Cohen et al 1991). Some studies have already been carried out for endangered species of cacti examining conservation initiatives such as micropropagation in vitro (Marchi 2016;Palacios et al 2016;Civatti et al 2017a;Torres-Silva et al 2018), living collections (Hultine et al 2016;Cavalcante et al 2017) and seed storage (Civatti et al 2015;Nascimento & Meiado 2016;Santos et al 2018); these works are crucial to facilitate future studies and to protect the species from extinction.…”

Clonal propagation of Trichocentrum stramineum (Orchidaceae), a threatened species endemic to Mexico

“…Cloning also occurs naturally in wild plants and is sometimes more efficient than sexual propagation, e.g., favorable genotypes that contribute descendants by both sexual and asexual reproduction may perpetuate their genes within a population for generations (Gentry 1982, Nobel 1985, 1992. In the case of populations facing imminent extinction, represented by a few unique genotypes only, repeated small scale clonal multiplication can be the last resort to avoid vanishing of the former (Mistretta 1994, Martínez-Palacios et al 2016). An efficient cloning method distinguishes itself by simple and shortterm cultivation processes that promote direct morphogenic responses.…”