In vitro propagation of seven Daphne L. species

Abstract

Cultures of seven Daphne species: Daphne caucasica, D. cneorum, D. giraldii, D. retusa, D. jasminea, D. laureola and D. tangutica were established in vitro on MS/WPM based media. Five of the species responded best on MS-based media (D. tangutica, D. laureola, D. caucasica, D. retusa and D. giraldii), while the remaining two species performed best on WPM-based media (D. cneorum, and D. jasminea). Shoot proliferation was achieved from both apical and nodal explants. Shoots were sub-cultured from stock cultures, cut into nodal explants 3-5 cm long and place vertically on basal media supplemented with different concentrations and combinations of cytokinins and auxins. Individual species displayed different responses to the various cytokinins and auxins. Among species, D. jasminea produced the greatest proliferation rate with an average of 7.84 ? 0.6 shoots per explant on WPM supplemented with 2.32 lM BA ? 0.0045 lM TDZ ? 0.054 lM NAA, while the best multiplication rate for the same species grown on the same media supplemented with a single cytokinin (BA) and no auxin was 2.60 ? 1.3 shoots per explant. Following multiplication, new shoots transferred to the elongation trails and then 50-100 mm Shoots used for rooting experiments. Increased rooting efficiencies were observed on in vitro-generated shoots with the two-layer medium or dipping methods over when PGRs were uniformly incorporated into the medium.Maximum rooting frequencies (average) ranged from 59% in D. tangutica to 85% in D. jasminea. Following in vitro rooting, rooted shoots immersed in 0.01% solution of humates and planted into a standard horticultural substrate composed and watered weekly with a solution containing half-strength MS salts.

Micropropagation of Cotoneaster wilsonii Nakai—a rare endemic ornamental plant

“…In this study, high concentrations of TDZ (1.5-2.0 mg L -1 ) and repeated subculture resulted in hyperhydric shoots. A similar result has been reported by several researchers in many woody plant species (Caboni et al 1999;Kadota and Niimi 2003;Bosela and Michler 2008;Noshad et al 2009;Feng et al 2010). Hyperhydricity can be induced by different stress conditions (Kevers et al 2004).…”

Promoting root induction and growth of in vitro macadamia (Macadamia tetraphylla L. ‘Keaau’) plantlets using CO2-enriched photoautotrophic conditions

“…However, a large amount of shoot tip necrosis ([80%) had been reported when the plantlets were grown under the two-step culture process in a medium of MS supplemented with 3 mg l -1 IBA for 4 weeks, before transferral to PGR-free MS agar solidified medium. The protocol of root induction through the two-step process has been applied in various woody species (Nand et al 2004;Sharma et al 2007;Tamta et al 2008;Noshad et al 2009). …”

“…(Tamta et al 2008), Davidson's Plum (Davidsonia jerseyana), Queensland Davidson's Plum (D. pruriens) (Nand et al 2004), and seven Daphne (Daphne sp.) (Noshad et al 2009) and apple rootstocks (Malus domestica) (Sharma et al 2007). Although there are many successful micropropagation protocols, abnormal growth and development of plantlets obtained from micropropagation have been reported, including shoot-tip necrosis, hyperhydricity, chimeric tissue in callus-root formation, and recalcitrant root induction.…”

Plant tissue culture: Current status, opportunities and challenges

“…A plant tissue is considered to be "introduced and established" to the in vitro culture when explants are not only free from superficial or visible contaminants, which interfere with the morphogenic response, but also when it shows a morphogenic response. This morphogenic response is characterized by multiplication and/or differentiation of the plant tissues such as: shoots, roots, leaves or production of calli (Noshad et al, 2009;Christensen et al, 2008).…”