Multiple Plant Regeneration from Embryogenic Calli of Paulownia tomentosa (Thunb.) Steud

The aim of this paper was to study the effect of plant growth regulators on callus induction and in vitro morphogenesis using various explants of Paulownia tomentosa to develop an efficient plant regeneration protocol. Different plant organ sections (leaves, apical shoot tips, petals, nodes, and internodes) were cultured as explants to identify the best in vitro explants responsive to callus induction and plant regeneration. Explants were cultivated on MS media supplemented with different concentrations of plant growth regulators (TDZ (Thidiazuron), BAP (6-Benzylaminopurine), kinetin, and NAA (1-Naphthaleneacetic acid). It was discovered that the addition of TDZ and NAA stimulated the induction of somatic embryogenesis. It was discovered that the MS medium with the combination of plant growth regulators BAP (35.5 mu M) and NAA (5.4 mu M) with the addition of 30.0 g/L maltose, 500.0 mg/L casein hydrolysate, and 250.0 mg/L L-proline was optimal for callus induction and multiple plant regeneration. The study of the regenerative capacity of various explants of Paulownia tomentosa in vitro showed that plant regeneration depends on the type of explant, and occurs in both ways, indirectly, through the formation of callus tissues and directly on the explant, without callus formation. As a result of this study, the efficient reproducible protocol of embryogenic callus formation and multiple shoot induction in vitro of Paulownia tomentosa was developed. This system provides a clear increase in the frequency of plant regeneration from 36.3 +/- 3.4% to 38.6 +/- 2.3% per embryogenic callus from leaves and apical shoot tips, respectively.

Automated summary

The aim of this study was to investigate the effect of plant growth regulators on callus induction and in vitro morphogenesis of Paulownia tomentosa and develop an efficient plant regeneration protocol. It was found that the addition of TDZ and NAA stimulated somatic embryogenesis, while the combination of BAP and NAA was optimal for callus induction and multiple plant regeneration. The regenerative capacity of P. tomentosa varied depending on the type of explant, occurring through both callus formation and direct regeneration. Overall, this study successfully developed a reproducible protocol for embryogenic callus formation and multiple shoot induction in vitro, leading to an increased frequency of plant regeneration.