In vitro Callus Induction and Plant Regeneration of Celosia argentea- An Important Medicinal Plant

Celosia argentea (Var.) cristata (Amaranthaceae) is a widely cultivated ornamental plant, which has antibacterial, astringent, haemostatic, hypertensive, ophthalmic, and parasitic significance. This study describes a protocol for in vitro callus induction and plant regeneration from leaf and stem explants of C. argentea using Murashige and Skoog (MS) medium. Callus culture was initiated and established from seedling, leaf, and stem explants. Explants were cultured on MS medium supplemented with auxin alone (0.5 mg/L Naphthaleneacetic acid (NAA), 2, 4-Dicholorophenoxyacetic acid (2, 4-D). Green and red compact callus (98%) were induced using MS medium supplemented with 0.5 mg/L NAA and 1.0 mg/L Benzyladenine (BA). Two different concentrations (1.0 mg/L BA + 0.5 mg/L NAA and 1.0 mg/L BA + 1.0 mg/L NAA) successfully induced plant regeneration with multiple shoots (1.5 and 0.9 shoots per explants, respectively). Successful shoots were transferred to rooting medium supplemented with 1.0 mg/L Indole-3-acetic acid (IAA) (80%) at 35th day. Acclimatization was done, which resulted in 90% of the plantlets surviving in garden soil. This protocol could be used to micropropagate C. argentea for conservation, commercial natural product production. The high frequency of callus indicated potential of C. argentea for secondary metabolite production (celosin) in pharmaceutical industry.

Physiological Responses of Callus from Gerbera jamesonii Bolus ex. Hook f. to Gamma Irradiation

In the present study, in vitro mutagenesis techniques were applied to investigate the effects of gamma irradiation at 0, 10, 20, 30, 40, 50 and 60 Gy on physiological changes in callus of Gerbera jamesonii Bolus ex. Hook f. Biochemical changes in chlorophyll and soluble protein content of pre- and post- irradiated Gerbera callus were studied. Non-irradiated callus demonstrated the highest amount of chlorophyll content as compared to callus irradiated at 10, 20, 30, 40, 50 and 60 Gy. In addition, the amount of chlorophyll b was relatively higher than chlorophyll a in both the irradiated and non-irradiated callus, except for callus irradiated at 10 Gy. Biochemical differentiation based on total soluble protein content revealed gradual reduction after day 9 of exposure to gamma irradiation. Reduction of soluble protein content was observed in all the treatments as the increase of incubation period.

Effect of picloram, additives and plant growth regulators on somatic embryogenesis of Phyla nodiflora (L.) Greene

The present study describes the plant regeneration via somatic embryogenesis in suspension culture derived from the leaf and stem explants of Phyla nodiflora. The medium type, plant growth regulators, complex extract (coconut milk and malt extract) and anti-oxidant (activated charcoal, ascorbic acid, Polyvinylpyrrolidone and citric acid) markedly influenced the embryo regeneration of P. nodiflora. MS with 2,4-D and activated charcoal (10 mg/L) gave the highest stimulation of embryogenic callus growth. Optimized callus was transfered into suspension culture, which showed the globular, heart shaped embryos in MS with 2,4-D + BA + picloram (0.1 mg/L), coconut milk (10 ml/L), citric acid (100 mg/L) on 6th subcultures. Further development stages such as torpedo and cotyledonary stage embryos and fostered maturation of embryos were observed at 8th and 10th subculture. However, the high frequency embryo germination and plantlet (45 plants/20 mg cotyledonary stages embryos) formation was obtained in half-strength MS medium without growth regulators from cotyledonary embryos. All the plantlets established in the field exhibited morphological characters similar to those of the mother plant.