Micropropagation of Buttonwood Tree (Conocarpus erectus) through Axillary Shoot Proliferation

Abstract

<jats:p>A method for micropropagation of <jats:italic>Conocarpus erectus</jats:italic> through axillary shoot proliferation is presented. Shoot tips were excised from adult donor tree and cultured for 4 weeks on Murashige and Skoog’s (MS) medium supplemented with 3 mg·L<jats:sup>−1</jats:sup> gibberellic acid (GA<jats:sub>3</jats:sub>) to induce sprouting of shoots and formation of axillary shoots. <jats:italic>Conocarpus erectus</jats:italic> shoots were cultured for 6 weeks on MS medium supplemented with different concentrations and combinations of plant growth regulators (PGRs) and proliferation of the shoots was monitored. The type and concentration of cytokinins applied had a significant influence on shoot proliferation responses. Supplementation with 6-benzylaminopurine (BAP) increased the rate of shoot proliferation compared with other cytokinins. The use of BAP in combination with auxins such as indole-3-butyric acid (IBA) and naphthalene acetic acid (NAA) resulted in an increased number of shoots per explant compared with treatment with BAP alone. A combination of 2 mg·L<jats:sup>−1</jats:sup> BAP and 0.5 mg·L<jats:sup>−1</jats:sup> IBA produced the highest number of axillary shoots (7.8 shoots/explant). The best rooting medium was full-strength MS medium supplemented with 1 mg·L<jats:sup>−1</jats:sup> IBA; this treatment yielded 80% rooting with an average of 3.5 roots per plantlet. All regenerated plantlets were successfully acclimatized to greenhouse conditions.</jats:p>

Micropropagation to Conserve the Endangered Gabal Elba Dragon Tree (Dracaena ombet Heuglin ex Kotschy & Peyr)

“…Our results indicate that lowering the salt strength in the medium to half resulted in 100% rooting of D. ombet, regardless of the concentration of IBA or NAA used. These results confirm previous findings on in vitro rooting of woody plant species such as Cassia angustifolia (Agrawal and Sardar 2007), Conocarpus erectus (Dewir et al, 2018), and Syzygium cordatum (Dewir et al, 2011), wherein the rooting was dependent on medium strength and the type and concentration of auxins. Regenerated plantlets of D. ombet were acclimatized to ex vitro conditions ( Fig.…”

“…Successful shoot proliferation using BAP in combination with auxin has been reported in other Dracaena species, including D. deremensis (Singh et al, 2001), D. fragrans 'Massangeana' (Aziz et al, 1996), and D. marginata 'Tricolour' (El-Sawy et al, 2000). The synergistic increase in shoot proliferation as a result of the BAP and auxin combination has been reported in woody plant species, including, Arbutus unedo (2 mg · L -1 BAP and 0.5 mg · L -1 NAA; El-Mahrouk et al, 2010), Conocarpus erectus (2 mg · L -1 BAP and 0.5 mg · L -1 IBA; Dewir et al, 2018), and Lessertia frutescens (0.5 mg · L -1 BAP and 0.1 mg · L -1 NAA; Shaik et al, 2010).…”

Inhibition of browning problem during the callogenesis of Spartium junceum L.

“…No bacterial infection in other PVP-pretreated explants was observed because PVP was capable of reducing phenol leakage, and hence it supported preservation of high levels of phenolic compounds in explants to keep pathogens back from growing. In mango, significant reduction in infection extent was observed on explants treated with PVP (Krishna et al, 2008). In present study, it was found that applying PVP 0.5% to callogenesis culture medium of S. junceum L. prevented explants from browning.…”

“…However, they are able to induce necrotic explant and cell death in high concentration, and so cause browning of explants (Mahmoud and Al-Ani, 2016). In order to reduce browning degree, a number of approaches have been suggested (Krishna et al, 2008;Momeni et al, 2017).…”

Micropropagation of licorice (Glycyrrhiza glabra L.) by using intermediate nodal explants

“…Tissue browning occurs because of the accumulation and subsequent oxidation of phenolic compounds in the tissue and culture medium (Krishna et al, 2008;Uchendu et al, 2011). Oxidative browning causes slow growth and eventually leads to cell/tissue or plant death (Krishna et al, 2008;Dewir et al, 2018a) and has been reported to hinder the establishment of cultures of G. glabra (Shah and Dalal, 1980). Several other plant species such as Arbutus unedo (El-Mahrouk et al, 2010) and Conocarpus erectus (Dewir et al, 2018a) were also affected by oxidative browning.…”