The effect of thidiazuron on the in vitro shoot development of endemic Astragalus cariensis in Turkey

Abstract

Thidiazuron (TDZ) is a cytokinin-like substance that has often been used for shoot regeneration in recent years. We observed the effect of TDZ on callus formation and shoot regeneration from leaf and petiole explants of the endemic species Astragalus cariensis Boiss. Explants were cultured on Murashige and Skoog (MS) media including TDZ (in concentrations of 0.2, 0.4, or 0.6 mg/L) or in combination with \alpha-naphthaleneacetic acid (NAA) (in concentrations of 0.2 or 1.0 mg/L). Significant variations in the frequency of callus formation and the morphogenesis of the callus were obtained depending on the explant type. Petiole explant was determined to be the best for callus formation, but calli from leaf explants were more responsive in terms of shoot formation. MS media including TDZ and NAA showed 100% callus formation, but shoot regeneration was enhanced by TDZ combined with a low concentration of NAA. The highest number of shoots, (15 per explant) was induced from leaf explants on MS medium with 0.4 mg/L TDZ and 0.2 mg/L NAA. Regenerated shoots were rooted in MS medium containing 0.5 mg/L indole-3-butyric acid (IBA). The rooted plantlets were acclimatised and produced normal plants.