In Vitro Clonal Propagation of Vanilla (Vanilla planifolia ‘Andrews’)

Abstract

<jats:p>A complete and efficient regeneration protocol was developed for <jats:italic>Vanilla planifolia</jats:italic> ‘Andrews’, an endangered orchid species that represents an important crop in several tropical countries. Axillary buds excised from the first to the eighth node, considering the first to fourth nodes as “young” (zone 1) and the fifth to eighth as “mature” (zone 2), were cultured on Murashige and Skoog (MS) medium supplemented with 5.73, 7.64, 9.55, or 11.46 μ<jats:sc>m</jats:sc> 6-benzylaminopurine (BA) for shoot induction and in combination with 4.45 μ<jats:sc>m</jats:sc> naphthalene acetic acid (NAA) to induce multiple shoot proliferation. Cytokinin concentration and bud position in the stem had a significant effect on the number of shoots regenerated. The greatest shoot formation per explant, for the two tested zones, was obtained with 9.55 μ<jats:sc>m</jats:sc> BA on MS medium supplemented with 100 mg·L<jats:sup>−1</jats:sup> myoinositol, 150 mg·L<jats:sup>−1</jats:sup> citric acid, 100 mg·L<jats:sup>−1</jats:sup> ascorbic acid, and 20 g·L<jats:sup>−1</jats:sup> sucrose. Young buds from zone 1 were able to form an average of 18.5 ± 2.4 shoots per explant, whereas buds from zone 2 induced a maximum of 11.0 ± 1.0 shoots per explant. Plants of 2 to 3 cm height developed a root system in half-strength MS medium supplemented with 0.44 μ<jats:sc>m</jats:sc> NAA and, once they reached 5 cm height on average, were transferred to greenhouse conditions for their acclimatization where a 100% rate survival was achieved. The optimal use of both young and mature buds from each mother plant to induce adventitious shoots permitted a marked increase in the number of shoots per explant. By using all buds from the upper stem part (zone 1 + zone 2) and subculturing every 90 d, the multiplication rate was 1.1 to 1.86 × 10<jats:sup>5</jats:sup> shoots per bud per year.</jats:p>

Topophysic effects differ between node and organogenic cultures of the eucalypt Corymbia torelliana × C. citriodora

“…Pre-existing meristematic structures are not evident in the Alstroemeria leaf axils, but adventitious shoot production is induced by a treatment of thidiazuron and IBA followed by BA, which promotes the development of meristemoids from nodal epidermal cells (Lin et al 1998). Shoot production declines from 18.5 to 11.0 shoots per explant between the four most-apical nodes and the next four nodes of Vanilla planifolia shoots (Lee-Espinosa et al 2008). These authors described the BA-induced V. planifolia shoots as 'adventitious' although their cellular origin, like those of C. torelliana 9 C. citriodora, has not been determined histologically.…”

“…Positional effects on subsequent growth or development of explants or cuttings are termed 'topophysis' (George 1993;Mitchell et al 2004). Topophysic effects can be large, and an understanding of topophysis for optimised selection of initial explants can significantly improve the efficiency of a micropropagation system (Cheng et al 1992;George 1993;D'Souza and Sharon 2001;Lee-Espinosa et al 2008).…”

Optimisation of plantlet regeneration from leaf and nodal derived callus of Vanilla planifolia Andrews

“…Traditionally, it is propagated by stem-cutting; however, this method is labour-intensive, time-consuming (Kalimuthu et al 2006;Janarthanam and Seshadri 2008) and not economically viable, as the collection of the stem cuttings from mother plants may cause retardation of their growth and reduce yield (Davidonis and Knorr 1991;Geetha and Shetty 2000;Kalimuthu et al 2006). In Mexico, vanilla growers confront many challenges when producing vanilla vines, including meeting official standards and the production of sufficient plant material to satisfy the increasing demand for vanilla vines (Lee-Espinosa et al 2008). Therefore, a viable and simple method for the large-scale production of vanilla plants using tissue culture is required.…”

Multiplication and cryopreservation of vanilla (Vanilla planifolia ‘Andrews’)

“…In vitro multiplication of vanilla is a process that usually takes around 4 to 5 months, even under optimal conditions. An improved multiplication rate was previously obtained by Lee-Espinosa et al (2008), with subcultures performed at 90-d intervals. The use of IFEs as described in this study, despite the initial delay required to produce shoots, provides a new and simple method to generate large amounts of high quality explant material.…”

“…In vitro multiplication of V. planifolia has been reported using different culture media and propagules including callus (Gu et al 1987;Davidonis and Knorr 1991), protocorms, root tips (Phillip and Nainar 1986), and axillary-bud explants (Kononowicz and Janick 1984;George and Ravishankar 1997;Lee-Espinosa et al 2008). The first work on in vitro culture of vanilla, cited by Knudson, was performed by Bouriquet with germinating seeds in 1947 (Knudson 1950).…”