Substitution of benzyladenine with meta-topolin during shoot multiplication increases acclimatization of difficult- and easy-to-acclimatize sea oats (Uniola paniculata L.) genotypes

Abstract

Benzyladenine (BA) is the only cytokinin to effectively induce shoot multiplication in vitro between genotypes of the important dune grass species Uniola paniculata (sea oats). However, a significant genotypespecific negative carryover effect of BA on ex vitro acclimatization has been observed. In the present study, the effects of multiplication media supplemented with metatopolin (mT), a BA-analog, BA or no plant growth regulator, were compared on in vitro multiplication, rooting and ex vitro acclimatization using easy-and difficult-to-acclimatize sea oats genotypes. Both genotypes exhibited similar in vitro shoot dry weight, number of harvestable shoots and percent rooting when cultured under standard conditions (with 2.2 lM BA) or with an equimolar concentration of mT. In addition, both genotypes exhibited similar ex vitro leaf length and shoot production under these two culture conditions. However, ex vitro acclimatization of rooted microcuttings of the difficult-to-acclimatize genotype significantly increased when produced on shoot multiplication medium containing mT rather than BA. Metatopolin concentrations 10 lM or greater were inhibitory to in vitro rooting and acclimatization ex vitro of both genotypes. Nevertheless, survival of the difficult-to-acclimatize genotype was significantly greater when cultured in the presence of 2.2 lM-30 lM mT, compared to 2.2 lM BA. Therefore, a potential solution to overcome the detrimental BA carryover effect on ex vitro survival in sea oats is the substitution of BA with 2.2 lM mT for Stage II shoot multiplication. Use of mT may provide an efficient method to ensure in vitro propagation of a large number of diverse sea oats genotypes for dune restoration.

Topolins: A panacea to plant tissue culture challenges?

“…Williams) compared to BA (Bairu et al 2008). Valero-Aracama et al (2010) observed that mT at 10 lM or higher had inhibitory effects on the in vitro rooting of two Uniola paniculata genotypes. Similarly, Escalona et al (2003) in a study on plantain cv.…”

“…Consequently, these metabolites interfere with rooting and acclimatization competence in micropropagated plantlets (Werbrouck et al 1995). As demonstrated by Valero-Aracama et al (2010), BA treatment caused detrimental biochemical, physiological and developmental effects in Uniola paniculata cultures that resulted into reduced acclimatization competence. The authors discovered that similar problems were absent in mT treatments; which is a further indication of the relative lower toxicity of mT over BA and its analogues.…”

Epigenetics in plant tissue culture

“…One possible improvement of the procedures is in the choice of cytokinin. In micropropagation usually benzylaminopurine (BAP) is added but another cytokinin, metatopolin, is often just as effective with respect to the breaking of apical dominance (so resulting in a similar propagation factor) but has less negative side-effects (Bogaert et al 2006;Valero-Aracama et al 2009; but see Bairu et al 2008).…”

Effects of Plant Growth Regulators on in vitro Propagation of Echinosophora koreensis Nakai

“…BA is the first-generation artificial synthetic cytokinin, and known as one of effective PGRs widely used for in vitro propagation of sea oats (Valero-Aracama et al 2010), shoot regeneration of Tripterospermum japonicum (Moon et al 2009) and Anthocephalus cadamba (Kavitha et al 2009), shoot tip culture for horseradish propagation , and so on. TDZ, which has been highly effective in many in vitro plant propagation trials, is one of non-purine synthetic cytokinins, and known as a PGRs used among wide range of species (Amutha et al 2006), such as Vitex trifolia L. (Ahmed and Anis 2012), Salix tetrasperma R. , and butterfly pea (Seemab et al 2012).…”