Callus Induction, Proliferation, Enhanced Secondary Metabolites Production and Antioxidants Activity of Salvia moorcroftiana L. as Influenced by Combinations of Auxin, Cytokinin and Melatonin

Tissue culture technique is one of the best methods to reproduce salvia plant Therefore, the aim of this research was to enhance the in-vitro callus proliferation and production of secondary metabolites of S. moorcroftiana using different combinations of auxin, cytokinin and melatonin. Initially, callus induction was optimized using indole acetic acid (IAA), 2, 4-dichlorophenoxy acetic acid (2,4-D), and naphthalene acetic acid (NAA) applied at different concentrations in combination with 1 mg L-1 of 6-benzylaminopurine (BAP). The results indicates that earliest days to callus induction (14.67 days) was occurred in the media fortified with 2, 4-D+BAP (2.0+1.0 mgL-1). Whereas the highest callus initiation (100%) was induced on MS medium incorporated with 2,4-D+BAP (1+1mgL-1). Furthermore, maximum fresh weight was obtained when 2,4- D + BAP at the rate of (1+ 1mg L-1) was incorporated and dry weight was attained when 2,4- D + BAP at the rate of (2+1 mg L-1) was added to MS media. The maximum fresh and dry weight was obtained when melatonin at rate of 1.5 mg L-1 was supplemented with MS media including 2,4-D + BAP (1+1mg L-1), moreover the maximum DPPH scavenging activity, total phenolic and flavonoid content was noted when supplemented with melatonin at rate of 1.5 mg L-1. In conclusion, among various concentrations of plant growth regulators, 2,4- D + BAP at the rate of (1+ 1mg L-1) along with 1.5 g L-1 melatonin was the best for callus growth and production of secondary metabolites of S. moorcroftiana.