Propagation of Ornamental Plants
17(2): 64-74, 2017
EFFICIENT PROPAGATION OF NERIUM OLEANDER L. THROUGH TISSUE CULTURE
Stefanos Hatzilazarou1*, Stefanos Kostas1, Athanasios Economou1, and Apostolos Scaltsoyiannes2
1 School of Agriculture, Aristotle University, 54124 Thessaloniki, Greece, *Fax: +30 2310 998679, *E-mail: hatzilaz@agro.auth.gr 2 School of Forestry and Natural Environment, Aristotle University, 54124 Thessaloniki, Greece
Efficient micropropagation protocol was developed for a selected clone of Nerium oleander used as flowering pot plant. Initial shoot tip explants excised from oleander plants were successfully disinfested in 0.1% HgCl2 and 2.0% NaOCl and after establishment in vitro performed better on the nutrient media WPM and MS than on DKW or B5. In vitro-derived axillary shoots showed highest multiplication rates (76.7%) on WPM supplemented with 10 μM BAP than the rest of variants supplemented with 2iP, Kinetin, and TDZ at different concentrations (5, 10 or 20 μM) in 4-week subculture period. BAP at concentrations of 20 and 10 μM promoted significantly stronger proliferation (2.8 and 2.5 shoots, respectively) than the other cytokinins. Adequate shoot rooting occurred (60.0-66.7%) in agar-solidified WPM with addition of 0.5 or 2 μM IAA, IBA or NAA compared to the control (22.2%), producing thick and unbranched roots. Rooting in vitro in inert substrates (peat, perlite, and their mixture), saturated with liquid WPM supplemented with 0.5 μM IBA, displayed higher rates (75.6-80.0%) than those on the same, but plant growth regulator-free variants (37.8-48.9%). Rooting ex vitro when using the same water-moistened inert substrates reached even higher rates (91.1-97.8%) either with or without IBA. In inert substrates, the roots formed both in vitro and ex vitro were branched and had thin root hairs. The survival rate of the acclimatized in the greenhouse plantlets was 100% for those derived from shoots rooted in substrates (in vitro or ex vitro) and 93.3% for those rooted in vitro in agar-solidified WPM. Following acclimatization, young plantlets were successfully transferred to field conditions without losses.
Key words: acclimatization, inert substrates, micropropagation, oleander, ornamental pot plants, rooting, shoot multiplication
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