TITLE:
Cytokinin, Carbon Source, and Acclimatization Requirements for in Vitro Propagation of Scutellaria barbata D. Don and Scutellaria racemosa Pers.
AUTHORS:
Terri Ann Brearley, Brajesh Nanda Vaidya, Nirmal Joshee
KEYWORDS:
Antioxidant, 6-Benzylaminopurine, Flavonoid, meta-Topolin, Polyphenol, RIM, SIM
JOURNAL NAME:
American Journal of Plant Sciences,
Vol.5 No.24,
December
1,
2014
ABSTRACT: Micropropagation protocols to minimize hyperhydricity were optimized for medicinal Scutellaria barbata and Scutellaria racemosa. Six cytokinins and eight different carbon sources at two different incubation periods of 14 and 21 days were studied for adventitious shoot bud induction using nodal explants. In S. barbata, 5 μM meta-Topolin and 0.1 μM NAA supplemented shoot induction medium produced four shoots each after 14 and 21 day incubation. Observation of S. racemosa nodal explants recorded four and five shoots after 14 and 21 day incubation. In both species, control explants (no plant growth regulators in the medium) consistently resulted in the bud break with two shoots in both 14 and 21 day incubation. The effect of carbon source on shoot regeneration was studied by supplementing eight different sugars at 0.1 M concentration to the optimized shoot induction medium (5 μM meta-Topolin and 0.1 μM NAA). S. barbata nodal explants cultured on shoot induction medium supplemented with fructose and glucose for 14 days produced 10 and nine adventitious shoots respectively; and after 21 day incubation adventitious shoot count reached 19 in glucose supplemented medium. S. racemosa explants in the same experiment produced five shoots in maltose and four shoots in sorbitol supplemented medium after 14 day incubation; whereas after 21 day incubation, sucrose and maltose produced five shoots; fructose, glucose, and sorbitol produced four shoots. Regenerated plants were successfully acclimatized and Scanning Electron Microscopy of the leaf surface revealed differences in stomatal behavior and cuticle deposition between in vitro and acclimatized plants. The antioxidant assay conducted on both Scutellaria species showed considerable total polyphenol content, TEAC activity and flavonoid content in fresh and dried leaf samples attributing to their medicinal potential.