In vitro propagation of oil-bearing Rosa damascena using phloroglucinol: A protocol for rapid and high-quality shoot multiplication and rooting

Abstract

Damask rose (Rosa damascena Mill.), of the family Rosaceae, is an important ornamental-medicinal, essential oil-bearing species. Due to its economic value, the aim of this study was to establish a new protocol for the in vitro propagation of R. damascena ‘Isfahan' using phloroglucinol. Axillary bud explants, Murashige and Skoog (MS) medium, and combinations of various plant growth regulators (PGRs) were used for the development of an effective method for rapid and high-quality shoot multiplication and in vitro rooting of Damask rose ‘Isfahan’. In the establishment step, 0.1 mg·L–1 phloroglucinol (PG), 0.2 mg·L–1 gibberellic acid (GA3), 0.1 mg·L–1 indole-3-butyric acid (IBA) and 1 mg·L–1 6-benzylaminopurine (BAP) were used. Secondary explants (nodal segments containing an axillary bud), obtained after 30 days of culture, were transferred to the proliferation media enriched with different concentrations of PG (0, 0.1, 0.2 and 0.3 mg·L–1), BAP (0, 1, 2 and 3 mg·L–1) and IBA (0, 0.1, 0.2 and 0.3 mg·L–1). A total of 64 combinations of these PGRs were investigated as a factorial experiment on the basis of a completely randomized design. Results showed that the shortest time until bud break (4.3 days), the highest number of green leaves (13.3) and lowest number of yellow leaves (1.3) were obtained in the explants grown on the medium containing 0.3 mg·L–1 PG + 2 mg·L–1 BAP + 0.2 mg·L–1 IBA. The largest number of shoots (4.8), and the highest fresh (5.9 g) and dry (1.2 g) weight of roots per explant were produced in the medium supplemented with 0.2 mg·L–1 PG + 2 mg·L–1 BAP + 0.3 mg·L–1 IBA. The highest regeneration coefficient (2.53), stem length (6.47 cm), fresh (2.32 g) and dry (0.51 g) weight of stem were obtained in the medium with 0.2 mg·L–1 PG + 2 mg·L–1 BAP + 0.2 mg·L–1 IBA. On the other hand, the highest number of roots (4.7) per explant were produced in the media supplemented with 0.3 mg·L–1 PG + 2 mg·L–1 BAP + 0.3 mg·L–1 IBA. None of the shoots regenerated roots in the absence of IBA. In most measured traits, the lowest values of the measured traits were obtained in the control medium without PGRs. Rooted plantlets were transferred to pots containing perlite and peat moss in 2:1 proportion and acclimatized in a greenhouse with a mean 82% survival rate. The positive role of PG in micropropagation was confirmed. The obtained results are more efficient than the previously established ones. Therefore, this cost-effective protocol can be used for the in vitro mass propagation of R. damascena Mill.