2,4-Dichlorophenoxyacetic acid increases reserve compounds and spectaline contents in Senna spectabilis calli

Abstract

The aim of this study was to develop an in vitro culture system for Senna spectabilis and to quantify contents of storage compounds and spectaline in induced calli in relation to exogenous auxin. Explants (cotyledon, hypocotyl, epicotyl, and leaf) were cultured on MS medium containing different concentrations of 2,4-dichlorophenoxyacetic acid (2,4-D). The soluble carbohydrate, starch, soluble protein and spectaline contents in the induced calli were quantified. Treatment with 0.12 mg L^-1 of 2,4-D induced callus formation and was optimal for propagation and vegetative growth, owing to the higher concentrations of reserve compounds in the calli. Hypocotyl and epicotyl produced calli on medium containing 0.5 mg L^-1 2,4-D. The lowest concentrations of 2,4-D induced a higher incidence of oxidation and explants showed low viability. Spectaline accumulated at low concentrations in the different callus types and 2,4-D treatments, indicating spectaline was a constitutive compound in callus. Hypocotyl with 10.0 mg L^-1 2,4-D for up to five days induced cell proliferation and starch accumulation, followed by treatment with 0.12 mg L^-1 2,4-D to increase tissue mass and accumulation of reserve compounds enables the production of friable callus suitable for the establishment of a tissue culture system and for in vitro spectaline production.

Keywords: Alkaloid, auxin, Fabaceae, carbohydrate, tissue culture.

African Journal of Biotechnology, Vol 13(31) 3567-3575