Strigolactone analogue GR24 mediated somatic embryogenesis from leaf tissues of Santalum album L

Santalum album L. (Santalaceae) is an endangered tree species with high economic potential. To improve its cultivation, the role of strigolactone on the somatic embryogenesis of Santalum leaves was analyzed. Leaves were cultivated in vitro using GR24 (a synthetic analogue of strigolactone) at various concentrations (from 0.1 to 1.0 mg L −1 ) and meta -Topolin ( m T), and integrated microscopy of the somatic embryos was used to describe the structural developments underlying the ontogenesis from the leaf under the influence of GR24. The results showed that Murashige and Skoog medium containing 0.75 mg L −1 GR24 produced a maximum percentage (92.0%) of somatic embryos from the leaf surface and cut ends. Weekly microscopic examinations of cultured tissues showed callogenic primary cell masses and minor vascular bundles along the lamina after 3 wk. The proliferation of these primary cell masses led to the emergence of embryogenic outgrowths from leaf surfaces. The areas undergoing intense cell divisions possessed prominent nuclei. The microscopic examinations confirmed the distinctive developmental stages (globular, heart-shaped, and bipolar structures) of somatic embryos. The highest shoot regeneration frequency (88.9%) and shootlet proliferation were aided by the combined incorporation of 0.5 mg L −1 m T and 0.25 mg L −1 GR24. The regenerated plantlets were rooted and acclimatized successfully under ex vitro conditions with 91.0% survival in field conditions and possessed a normal phenotypic appearance. The described somatic embryogenic protocol can be effectively utilized for large-scale plantlet production, long-term storage, and genetic engineering studies in this multipotent tree species.