Effect of Cytokinins on In Vitro Propagation of Ajuga xylorrhiza Kit Tan (Critically Endangered), Endemic to Turkey

Ajuga xylorrhiza Kit Tan is a rare endemic perennial species growing in the stony habitats in Southeastern Anatolia region, Turkey. An efficient and reproducible protocol has been developed for micropropagation of endangered Ajuga xylorrhiza. Shoots were cultured on Murashige and Skoog (MS) basal medium, supplemented with various concentrations of 6-benzyl amino purine (BAP), thidiazuron (TDZ), and kinetin (Kin). The optimal shoot formation was with the medium containing 0.125 mg L−1 BAP (7.91 shoots per explant), and 0.25 mg L−1 Kin (4.9 shoots per explant) was recorded. The best result in terms of shoot length (3.43 to 3.63 cm) was obtained from the Kin treatments. Kin parameters were more effective on shoot length and multiple shoot production than BAP and TDZ. For rooting, regenerated shoots were transferred to 1/4 strength MS medium containing two different concentrations of indole acetic acid (IAA) and α-naphthalenetic acid (NAA) at 0 (control), 0.5, or 1.0 mg L−1.The best results in terms of the number of roots per shoot were obtained from the medium supplemented with 0.5 mg L−1 IAA (3.10 roots per explant). Rooted plantlets were transferred to soil for acclimization with 100% success rate.