Optimization of BAP- and NAA-Mediated In Vitro Micro propagation of Dendrobium

Abstract

The present study evaluated the effects of plant growth regulators on survival, shoot proliferation, and root development in Dendrobium Nobile under in vitro conditions. Shoot-tip explants were cultured on Murashige and Skoog (MS) medium supplemented with different concentrations of 6-benzylaminopurine (BAP; 0–2.5 mg/L) for shoot induction and multiplication, and with α-naphthalene acetic acid (NAA; 0.5–2.5 mg/L) for root induction. BAP significantly influenced shoot induction and multiplication, with the highest shoot-induction percentage (88.2%), number of shoots per explant (6.5), and mean shoot length (4.1 cm) recorded at 2.0 mg/L BAP. Root induction was significantly affected by NAA concentration, with 1.0 mg/L NAA producing the highest root-induction percentage (82.7%), number of roots per shoot (5.6), and mean root length (3.8 cm). Higher concentrations of both BAP and NAA resulted in reduced growth parameters, indicating inhibitory effects at supra-optimal levels. These findings indicate that 2.0 mg/L BAP is suitable for shoot multiplication, whereas 1.0 mg/L NAA is suitable for root induction in D. Nobile. The optimized protocol provides a basis for large-scale micro propagation and conservation of this orchid species.