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Melia dubia Cav. (Meliaceae) is a multipurpose tree of tropical and subtropical regions mainly cultivated for its medicinal and industrial importance. Due to its versatile properties, it has been depleted in its natural environment. Moreover due to sluggish and poor seed germination, there is a threat of its gene pool exclusion from the natural habitat. The alternative method for conservation and efficient mass propagation is thus need of the hour. As per the extensive literature survey there is no report on efficient protocol for mass propagation of M. dubia through callus organogenesis. Therefore, the present work was aimed to develop in vitro organogenesis protocol for rapid and large scale production of planting material. From our results, maximum callus percentage, callus weight and fragile callus was observed on 1.0 mg/l benzylaminopurine (BAP) in combination with 0.5 mg/l naphthalene acetic acid (NAA). The callus differentiation was achieved at different concentrations of BAP and indole acetic acid (IAA). Multiple Shoot number per callus propagule 5.30 was observed on 0.5 mg/l BAP and 1 mg/l IAA concentration. The maximum rooting percentage (78.5%), root number per explant (4.33) and root length per explant (4.41 cm) was observed at 0.5 mg/l indol butyric acid (IBA) after 30 days of inoculation. Further the total flavonoid content, phenolic content and antioxidant properties of leaves of in-vitro regenerated plants where studied. Total flavonoids and phenolic content in leaves of in vitro Melia dubia was 0.56 ± 0.8 mg quercitin equivalent (QE) and 2.97 ± 0.17 mg gallic acid equivalent (GAE) respectively. The antioxidant property was further assed through measurement of DPPH radical scavenging activity. The in-vitro regeneration protocol can be exploited for commercial cultivation and fulfilling the growing demand for fresh explant material through mass propagation of M. dubia an economically important plant species.

Bambusa nutans Wall. is a clump-forming, evergreen bamboo species that is most often found in Southeast Asian forests. Comparative activities of nitrate reductase (NR), glutamine synthetase (GS) and peroxidase (POX) as well as expression of peroxidase isozymes during somatic embryogenesis (SE) were investigated in the segregated embryogenic callus (EC) and non-embryogenic callus (NEC) from the same genotype (CPC-648) of B. nutans Wall. The EC was compact, with large prominent nuclei and dense cytoplasm, while the NEC was fragile, with rudimentary nuclei and hyaline cytoplasm. SE in EC encompassed induction, maturation and germination stages each of 30 days on MS medium supplemented with ascorbic acid 50mg/l, citric acid 25mg/l, cysteine 25mg/l and glutamine 100mg/l + 2, 4-D-2 mg/l + coconut water 10%. EC exhibited dedifferentiation and growth leading to SE, while NEC remained amorphous loose lump throughout. EC had lower NR and POX activities and less number of peroxidase isozymes but higher GS activity than NEC during three stages of SE. NR activity followed a trend as induction > germination > maturation (EC and NEC); GS activity, maturation > germination >induction (EC) and induction >germination >maturation (NEC) and POX activity, maturation > induction > germination (EC) and induction > germination > maturation (NEC). Compared to NEC, EC exhibited less peroxidase isozymes. SE is an epigenetically regulated process that leads to the expression of enzymes involved in primary metabolism in EC and secondary metabolism in NEC. GS activity corresponding to SE process may be developed as biochemical marker. A chaotic scenario, rather from being a marker of SE, is indicated by high levels of peroxidase activity and isozyme expression.

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