Micropropagation of Endemic and Endangered Mexican Species of Ponytail Palms

Abstract

<jats:p>Experiments were conducted to establish an efficient protocol of micropropagation of <jats:italic>Beaucarnea gracilis</jats:italic> and <jats:italic>B. recurvata</jats:italic> two endemic and endangered Mexican species. Multiple shoots were induced by direct organogenesis from in vitro seedlings and longitudinal sections of seedlings in both species. The highest formation of shoots per explant, both <jats:italic>B. gracilis</jats:italic> and <jats:italic>B. recurvata</jats:italic>, was obtained from longitudinal sections of seedlings on Murashige and Skoog (MS) medium supplemented with 22.2 μ<jats:sc>m</jats:sc> 6-benzylaminopurine, induced 8.2 and 11.1 shoots per explant respectively. In vitro rooting was readily achieved on MS medium with 1 g/l activated charcoal without growth regulators. According to initial treatment and depending on where the shoots come from, the rooting rates were 61% to 100% for <jats:italic>B. gracilis</jats:italic>, and 83% to 100% for <jats:italic>B. recurvata</jats:italic>. Survival rates in greenhouse conditions for both species were 80% to 100% after 3 months. These results indicate that the micropropagation of these species of <jats:italic>Beaucarnea</jats:italic> is technically feasible, and that in vitro culture is a useful option for the conservation and propagation of these important endangered species.</jats:p>

In Vitro Regeneration from Longitudinal Sections of Seedlings of Beaucarnea purpusii Rose, an Endemic and Endangered Species

“…According to our results, a concentration of 0.45 mM of TDZ induced the highest normal shoot production per explant (25.8), while causing a low average of hyperhydrated shoots (0.78) and the highest explant survival rate (90.3%) ( Table 1). These results are superior to those reported in previous studies of other species of Beaucarnea: for B. recurvata, there are some studies that reported the formation of 6 to 11 shoots per explant using different concentration of BA (Bettaieb et al, 2008;Osorio-Rosales and Mata-Rosas, 2005;Reyes et al, 2013;Sajeva et al, 1994;Samyn, 1997); for B. gracilis, Osorio-Rosales and Mata-Rosas (2005) and Reyes et al (2013) achieved the induction of 8.2 and 9.4 shoots per explant, respectively; regarding B goldmanii, 3.9 shoots per explant were obtained (Reyes et al, 2013); and for B. inermis, 15.7 shoot per explant were induced (Guill en et al, 2015). Moreover, the effect of the addition of different concentrations of TDZ in this process had not been previously studied for any of the Beaucarnea species.…”

“…Shoot formation occurred via direct organogenesis from longitudinal sections of B. purpusii seedlings cultured with different concentrations of cytokinins. Similar responses have been described for B. recurvata (Bettaieb et al, 2008;Osorio-Rosales and Mata-Rosas, 2005;Reyes et al, 2013;Sajeva et al, 1994;Samyn, 1997), B. gracilis (Osorio-Rosales and Mata-Rosas, 2005; Reyes et al, 2013), Beaucarnea goldmanii (Reyes et al, 2013), and B. inermis (Guill en et al, 2015).…”

“…These kinds of shoots proved nonviable and eventually caused the loss of entire explants through browning. However, this response has not been reported in other studies of different Beaucarnea species (Bettaieb et al, 2008;Osorio-Rosales and Mata-Rosas, 2005;Samyn, 1997). Hyperhydration has been linked to the species, the genetics of the donor plants, the endogenous and exogenous levels of PGRs, and the type and concentration of gelling agents (Cassells and Curry, 2001;Kevers et al, 2004;Scholten and Pierik, 1998).…”

“…In spite of the botanical and ornamental interest in Beaucarnea species, studies concerning their in vitro propagation are scarce. There are some reports for Beaucarnea recurvata (Bettaieb et al, 2008;Osorio-Rosales and Mata-Rosas, 2005;Reyes et al, 2013;Sajeva et al, 1994;Samyn, 1997), Beaucarnea gracilis (Osorio-Rosales and Mata-Rosas, 2005), and Beaucarnea inermis (Guill en et al, 2015), but to the best of our knowledge, there are no reports on in vitro propagation of B. purpusii.…”

In Vitro Propagation of Viburnum treleasei Gand., an Azorean Endemic with High Ornamental Interest

“…Micropropagation has great potential for the protection of endangered endemic taxa (Bramwell, 1990;Osorio-Rosales and Mata-Rosas, 2005) by allowing genotype maintenance and resolution of problems related to self-incompatibility, fertility, low seed production, and low germination. This technique has already been applied to several Azorean endemics such as Hypericum foliosum (Moura, 1998), Azorina vidalii, Angelica lignescens (Silva and Debergh, 1997), and Vaccinium cylindraceum (Pereira, 2006).…”