Propagation of Ornamental Plants
12(4): 220-228, 2012
NEW CYTOKININS – META-METHOXYTOPOLINS IN MICROPROPAGATION OF
COTINUS COGGYGRIA SCOP. ‛ROYAL PURPLE’
Małgorzata Podwyszyńska1*, Elżbieta Węgrzynowicz-Lesiak1, Karel Doležal2,3, Jan Krekule3, Miroslav Strnad2,3, and Marian Saniewski1
1Research Institute of Horticulture, Konstytucji 3 Maja 1/3, 96-100 Skierniewice, Poland, *Fax: + (48) 46 8333434, *E-mail: firstname.lastname@example.org
2Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University, Šlechtitelů 11, 783 71 Olomouc, Czech Republic
3Laboratory of Growth Regulators, Institute of Experimental Botany ASCR, Šlechtitelů 11, CZ 783 71, Olomouc, Czech Republic.
The effects of the new cytokinin, meta-methoxytopolin (MemT), and its riboside (MemTR), on the micropropagation efficiency and shoot quality of smoke bush (Cotinus coggygria Scop.) ‘Royal Purple’ were studied. This plant species is recalcitrant both in conventional and in vitro propagation. In this study, in vitro cultures of the axillary shoots of smoke bush ‘Royal Purple’ were used. In the experiment concerning the multiplication stage, new cytokinins were applied at concentrations of 0.5, 1 and 2 mg l-1. In the control, N6-benzyladenine (BA) at a concentration of 0.5 mg l-1 was selected based on the earlier studies. The Cotinus shoot cultures treated with MemT at 1 mg l-1 or MemTR at 1 and 2 mg l-1 demonstrated multiplication rates that were higher by 30-40%. The shoots were longer by 40-50% and contained 60% more chlorophyll as compared to the control. The shoots derived from variants of the medium containing meta-methoxytopolins, produced ethylene at the same level as those from the control medium. In order to evaluate the carry over cytokinin effects on rooting capacity, the shoots were preliminary cultured on variants of the medium containing all the cytokinins, including BA, at concentrations of 0.5, 1, and 2 mg l-1. After the second subculture, shoots were rooted on a medium containing 3 mg l-1 IBA. The cytokinins applied during the multiplication stage had a carry over effect on shoot capacity for rooting. Thus, meta-methoxytopolins at the concentration of 0.5 mg l-1, created carry over effect decreasing rooting percentage from 80% obtained for BA (0.5 mg l-1) to 51.9% and 65.2% for MemT and MemTR, respectively. If cytokinins were used at 2 mg l-1, the strongest carry over effect, inhibitory-to-rooting was observed for BA. Our results imply that meta-methoxytopolins can be considered an alternative to other commonly used cytokinins in micropropagation of recalcitrant species.
Key words: BA-derivatives, early senescence, in vitro propagation, smoke bush