Comparison of Three Cytokinins on In vitro Multiplication of Orbea semota, a Conical, Stout-Teethed Succulent

Abstract

Objective: Orbea semota (N.E. Br.) L.C. Leach is an erect or procumbent succulent with numerous branches. The stems of this plant are grey-green to dark green in color and possess flowers that are dark maroon or dark brown with yellow marks at the tips. It is native to Kenya, Tanzania and Rwanda and grows in rocky places. There is great potential for its use as a medicinal plant, also, there are immense prospects for commercial trade and cultivation of the succulent as an ornamental in Jamaica. The purpose of the study is to select the most effective cytokinin for the shoot multiplication of Orbea semota using stem cuttings. Methods: Young shoots were initiated for 6-8 weeks on a modified Murashige and Skoog (MS) medium. Initiated shoots were then cultivated on Media A, B, C and D for 8 weeks to promote shoot multiplication. These were modified MS media supplemented with three different cytokinins [6-γ, γ-Dimethylallylamino purine (2iP), 6-Benzylaminopurine (BA) and Kinetin] and a control without any cytokinins. Results: Medium A (containing 2iP) produced the best results at shoot multiplication than all other media used. The mean lengths of the shoots produced by Medium A were 19.0±11.4 mm and 10.5±3.8 mm. The mean number of shoots generated using Medium A were 3.4±1.3 and 4.0±1.9. These results were significantly greater than those of the shoots produced by all other media. Conclusion: The present study details an efficient and reproducible protocol for the in vitro shoot multiplication of Orbea semota. The results obtained showed that Medium A was the most optimal medium for promoting shoot multiplication. Therefore, of the three cytokinins investigated 2iP produced the best results at stimulating shoot multiplication and growth of Orbea semota.