Direct and callus-mediated protocorm-like body induction from shoot-tips of Dendrobium chrysotoxum Lindl. (Orchidaceae)

Abstract

An efficient method of mass propagation of Dendrobium chrysotoxum Lindl. was developed using a shoot-tip culture system. Both direct and callus-mediated formation of protocorm-like bodies (PLBs) occurred from the basal cut surface of explants. Frequency of callusing was best in the presence of 2 mM thidiazuron (TDZ) or N 6 -benzylaminopurine (BAP). The callus exhibited complete hormone autonomy for growth and differentiation of PLBs and was maintained for 18 months without any exogenous growth regulators, an aspect important for minimising somaclonal variation. However, the rate of callus growth and PLB formation varied with application of cytokinin and auxin. In addition, the callus exhibited a differential sensitivity to the exogenous cytokinins. While BAP promoted callus growth and PLB differentiation, TDZ was inhibitory to callus mediated PLB formation and caused extensive necrosis of callus. Although a-naphthaleneacetic acid (NAA) had no significant effect on the induction of callus, subsequent growth was best in its presence. Using a 3-month subculture period, a 69-fold increase in callus weight was achieved with 0.5 mM NAA, while as many as 133 PLBs could be obtained per 100 mg callus in the presence of 1 mM NAA. For direct PLB formation, the optimum cytokinin dosage was dependent upon the type of cytokinin used. While TDZ was most effective at a concentration of 1 mM (15 PLBs per explant), for similar PLB yield the application of 8 mM BAP was essential.

A Review on: In Vitro Cloning of Orchids

“…Oculatum in modified KC medium + 0.5 mg/L NAA + 1 mg/L BAP). However, Roy et al, (2007) observed the same response of D. chrysotoxum in modified MS medium + 2 mM TDZ/BAP.…”

“…Success in callus cultures in which the callus can be maintained for a prolonged period through subsequent subculture has been limited to a few orchids (Ishii et al, 1998;Chang and Chang, 1998;Roy and Banerjee, 2003). It is because of the uncertainties related to callus induction, necrosis, restricted growth and proliferation (Roy et al, 2007). Roy and Banerjee (2003) reported embryogenic callus induction from shoot tip explant of Dendrobium fimbriatum Lindl.…”

In Vitro Regeneration of Shoots From Nodal Explants of Dendrobium Chrysotoxum Lindl

“…In this condition, use of alternative explants helps in raising innumerable genetically identical clones. So far, the regenerative potential of stemnodes has been positively tested in some orchid species (Arditti & Ernst 1993;George & Ravishankar 1997;Vij & Kaur 1998;Kanjilal et al 1999;Gangaprasad et al 2000;Pyati et al 2002;Decruse et al 2003;Basker & Narmatha Bai 2006;Martin 2007;Zhao et al 2007;Janarthanam & Seshadri 2008;Medina et al 2009;Rangsayatorn 2009;Hong et al 2010;Kaur & Bhutani 2010).Till date, in vitro propagation of D. chrysotoxum was reported only through seeds (immature/mature), shoot-tips and protocorm segments culture (Xu et al 2001;Roy et al 2007;Kaur & Bhutani 2011).The objective of this study was to access the regeneration competence of stemnodes to multiply the D. chrysotoxum by subjecting them to varying physical and chemical stimulus in the medium.…”

Suplementos orgánicos para el cultivo in vitro del híbrido Laeliocattleya (Orchidaceae)

“…Particularmente el cultivo de semillas de orquídea in vitro ha permitido reducir los tiempos de producción de plántulas, ya que algunas especies pueden llegar a la madurez (producción de flores) en menor cantidad de años. Una gran cantidad de especies de orquídeas han sido cultivadas in vitro, mediante diferentes técnicas y varios propósitos (Roy et al, 2007;Huan et al, 2004b;Johnson et al, 2007). La mayoría ha sido propagada mediante la formación de estructuras conocidas como protocorm-like body (PLB).…”