In vitro regeneration and morphogenesis in Phyllanthus niruri L., an anti-plasmodial herb
We investigated the use of in vitro techniques for regeneration of adventitious shoots in Phyllanthus niruri, an anti-malarial plant as an initial effort towards its domestication. Fruits cultured on Murashige and Skoog (1962) basal medium (MS) supplemented with BAP had low germination (61%) due to seed coat imposed dormancy. The culture of nodal cuttings explants on BAP, kinetin or 2-isopentyl adenine (2iP) amended medium to avoid seed dormancy resulted in shoot regeneration without roots in all accessions with BAP producing the highest number of shoots (9.0). Subsequent inclusion of either 1-naphthalene acetic acid (NAA) or indole-3-butyric acid (IBA) in the BAP, kinetin or 2iP amended MS medium also produced only shoots. Leaf lobe explants cultured on only 2,4-dichlorophenoxy acetic acid (2,4-D) amended medium led to a significant calli development with 1 mg/L 2,4-D producing 100, 88.9 and 95.8% callus, respectively from Kwabenya, Kasoa and Aburi accessions. Subsequent transfer of calli to MS medium supplemented with 0.1 mg/L BAP led to calli growth (increase in weight) and morphogenic response depending on the concentration of 2,4-D in the induction medium. Only 55 and 25% of these calli from Kwabenya and Kasoa, respectively produced shoots while roots development was significantly higher ranging from 48 to 88.9%. These shoots did not survive ex-vitro acclimatisation due to hyperhydricity while those regenerated from nodal cuttings or seeds had high percentage survival. The high morphogenetic response of Phyllanthus niruri in vitro can be used to propagate this anti malarial plant and enhance its utilization in the treatment of malaria.
Key words: Shoot regeneration, morphogenic response, Phyllanthus niruri, accessions.