In vitro shoot regeneration and control of shoot tip necrosis in tissue cultures of Soymida febrifuga (Roxb.) A. Juss

Abstract

Soymida febrifuga (Roxb.) A. Juss., (Meliaceae) an indigenous lofty deciduous tree, endemic to India, has extensive pharmacological activity. Continuous destruction of plants due to environmental and geopolitical instability has posed a major threat to endemic tree species. In vitro propagation techniques are also problematic due to high incidence of shoot tip necrosis (STN). The effect of various culture conditions on regeneration and STN of Soymida febrifuga were investigated. Nodal segments from field grown plants were used as explants and cultured on MS supplemented with different concentrations of BA, KN, NAA and IAA. The synergistic effect of BA (2 mg/l) and NAA (0.2 mg/l) induced a mean of 6.3 ± 0.09 shoots from the nodal explants with a frequency of 80.4%. Frequent subculturing of nodal explants from in vitro derived shoots increases the number of multiple shoots, but the regenerated shoots exhibited the symptoms of STN. Various factors such as strength of the media, different carbon sources activated charcoal and different calcium sources have been investigated for reducing the incidence of shoot necrosis. STN can easily be recovered by increasing the levels of calcium. Transfer of shoots showing early signs of necrosis to half strength MS supplemented with CN (556 mg/l), CP (1.0 mg/l), AC (20 mg/l) and fructose (100 mg/l) facilitated recovery of more than 98% of the shoots. Rooted plantlets produced, using the optimized protocol, were acclimatized successfully.