Callogenesis of Moringa oleifera seed cotyledon

Abstract

Moringa oleifera has gained much importance in the past two decades due to its multiple uses and benefits to agriculture and industries. All the parts of the moringa plant are used for medicinal and other purposes. The roots, flowers, bark, stem, leaves and seeds of moringa possess antimicrobial properties, and hence it’s being regarded as a miracle plant. Different combinations of growth hormones have been used for plant tissue culture studies in M. oleifera but the difficulty in predicting a suitable medium for callus induction using different growth regulators in different localities is a major challenge. Studying the effect of different concentrations of growth hormones on callus induction of M. oleifera seed cotyledon is necessary to develop a reliable protocol for callus induction which is a prerequisite for the source of new metabolites which are not present in the wild. The seed cotyledon of indigenous M. oleifera seeds was used as an explant for callus induction. Seeds were surface sterilized with 90% ethanol for 1 min, washed 3 times with sterilized distilled water, surface sterilized using 3.5% aqueous solution of sodium hypochlorite containing few drops of Tween-20 for 10 min, followed by rinsing three times with sterile distilled water. The cotyledon explant was cultured on MS medium supplemented with different concentrations of 6- Benzyl amino purine (BAP), 2, 4-dichlorophenoxyacetic acid (2, 4-D) and α-naphthaleneacetic acid (NAA). Callus formation was monitored for a period of 5 weeks. The highest callus formation (90%) occurred on medium containing 1.0 mg/L BAP + 2.0 mg/L 2, 4-D + 0.5 mg/L NAA while the lowest callus formation (66%) was on medium containing 1.0 mg/L BAP + 2.0 mg/L 2, 4-D + 1.0 mg/L NAA. There was no callus formation on the medium lacking plant growth hormones. The T2 and T4 hormone combination would provide the basis for callus culture for the production of bioactive compounds and further in vitro genetic transformation in M. oleifera.