An efficient system for the production of clonal plantlets of the medicinally important aromatic plant: Salvia africana-lutea L.

Abstract

An in vitro cultivation protocol was developed for S. africana-lutea a species threatened by over collection due to its importance as an aromatic medicinal plant in the Western Cape of South Africa. Adventitious shoot induction was most successful using hypocotyls as explants for propagation on Murashige and Skoog (Physiol Plant 15:473–497, 1962) medium supplemented with 4.4 μM BA only; 2.7 μM NAA and 4.4 μM BA; or 2.9 μM IAA and 9.3 μM kinetin respectively. For continuous subculture, IAA and BA (μM) at a ratio of 2.9:4.4 or 2.9:8.9 had the best regeneration potential producing approximately three plantlets per nodal explant. Plantlets had 4–5 nodes that could be utilized for the following subculture phase to induce axillary shoots. The tissue culture of S. africana-lutea not only favoured rapid multiplication but was also characterized by seasonal in vitro flowering that was in synchrony with that of plants growing in the wild. This propagation regime has the capacity for producing 2000–3000 plants from one shoot after 3 four-week long subculture cycles, making it highly attractive for implementation as an in vitro conservation strategy. The micropropagated plants were easily acclimatized (88%) within a month after rooting in vitro and planted ex vitro in a sand:soil:peat moss:vermiculite (1:1:1:1; v/v) mixture.