In vitro shoot multiplication and plantlet regeneration from nodal explants of Cassia angustifolia (Vahl.): a medicinal plant Iram Siddique AE M. Anis Abstract An efficient, rapid and reproducible plant regeneration protocol was successfully developed for Cassia angustifolia using nodal explants excised from 14-day-old aseptic seedlings. Of the two cytokinins, 6-benzyladenine (BA) and thidiazuron (TDZ) evaluated as supplements to Murashige and Skoog (MS) medium, TDZ at an optimal concentration of 5.0 lM was effective in inducing multiple shoots. The highest rate of shoot multiplication was achieved on MS medium supplemented with 5.0 lM TDZ and 1.0 lM indole-3-acetic acid (IAA) at pH 5.8. The regenerated shoots when subcultured on hormone free MS medium considerably increased the rate of shoot multiplication and shoot length by end of fourth subculture passage. Rooting was achieved on the isolated shoots using MS medium with 60 lM indole -3-butyric acid (IBA) and 1% activated charcoal for 1 week and subsequently transferring the shootlets to half strength MS liquid media without IBA and activated charcoal. The in vitro raised plantlets with welldeveloped shoot and roots were successfully established in earthen pots containing garden soil and grown in greenhouse.

An efficient protocol of direct somatic embryogenesis (without involving intermediate callus) has been developed from stem segments and shoot tips of Capsicum annuum L. Explants were cultured on Murashige and Skoog (MS) medium supplemented with thidiazuron (TDZ). Among the various concentration of TDZ tested, 0.5 µM was proved to be best for induction of somatic embryos. Induction, maturation and germination were achieved on the same medium. The shoots developed from somatic embryos were transferred for rooting to MS medium supplemented with indole-3-butyric acid (IBA). All the regenerated plants with 85 % survival rate were normal with respect to morphology and growth characteristics.Additional key words: chilli pepper, direct somatic embryogenesis, growth regulators, in vitro. ⎯⎯⎯⎯Capsicum annuum L. is an economically important crop plant and two main consumption types of pepper spice and vegetable are prevalent throughout the world. In order to facilitate development of plant biotechnology based cultivar improvement for this species, considerable effort has been devoted in developing and optimizing efficient in vitro regeneration protocols. Plant regeneration via organogenesis and somatic embryogenesis from diverse explants using different concentration and combinations of auxin and cytokinins has been described in pepper (Harini and Sita 1993, Fari and Andrasfalvy 1994, Steinitz et al. 1999, Ochoa Alejo and Ramirez-Malagon 2001. In spite of these reports, reproducible methods for routine propagation are not available and existing methods are not satisfactory.Somatic embryogenesis, the production of bipolar structures from somatic cells is of considerable theoretical and practical importance because it can be used to combine efficient cloning with genetic modification (Sharp et al. 1980). In vitro somatic embryos can develop either from callus or directly from the explant without any intermediate callus stage. Since plant regeneration from callus cultures is often associated with genetic and cytological variations (Larkin and Scowcraft 1981) which are not always desirable, direct somatic embryogenesis has better applicability in the improvement of crops.Thidiazuron (TDZ), a substituted phenyl urea (N-phenyl-1,2,3-thidiazol-5-yl urea) is a potent plant growth regulator which exhibit cytokinin like activity in various culture systems. TDZ was successfully applied to induce organogenesis from different explants such as wounded seedlings, intact seedlings, leaf, cotyledonary nodes and shoot tip of pepper (Szasz et al. 1995, Hyde and Phillips 1996, Dabauza and Pena 2001, Venkataiah et al. 2003) but none of these reports have used TDZ for the induction of somatic embryogenesis.In this communication, we reported a high frequency regeneration system in chilli pepper through direct somatic embryogenesis from stem segment and shoot tip explants using TDZ, without involving callus phase.Seeds of Capsicum annuum L. cv. Pusa Jwala were presoaked overnight and washed under running tap water for 30 min to remove adherent pa...

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A rapid and efficient protocol for the large-scale propagation of a potential medicinal plant, Mucuna pruriens, through in vitro culture of nodal segment explants obtained from 15-day-old aseptic seedlings is described. Of the three different cytokinins, 6-benzyladenine (BA), kinetin (Kin) and 2-isopentenyl adenine (2-iP) evaluated as supplements to Murashige and Skoog (MS) medium, BA at an optimal concentration of 5.0 lM was effective in inducing multiple shoots. Strength of the basal media also influenced the efficiency of shoot regeneration. The frequency of shoot regeneration tended to increase when the salt concentration in the basal media was reduced. Highest number of multiple shoots (23.3) and maximum average length (5.6 cm) were standardised on half-strength MS medium supplemented with 5.0 lM BA along with 0.5 lM a-naphthalene acetic acid (NAA) at pH 5.8. Rooting was best induced in shoots excised from proliferated shoot cultures on MS medium augmented with an optimal concentration of 1.0 lM indole-3-butyric acid (IBA). The in vitro-raised plantlets with welldeveloped shoots and roots were successfully established in earthen pots containing garden soil and were grown in greenhouse with 90% survival rate. The results of this study provide the first report on in vitro plant regeneration of M. pruriens.

An efficient protocol has been developed for rapid micropropagation of Ocimum basilicum. Multiple shoots were induced by culturing shoot tip explants excised from mature plants on a liquid Murashige and Skoog (MS) medium supplemented with 5 -100 μM of thidiazuron (TDZ) for different treatment duration (4, 8, 12 and 16 d). The optimal level of TDZ supplementation to the culture medium was 50 μM for 8 d induction period followed by subculturing in MS medium devoid of TDZ as it produced maximum regeneration frequency (78 %), mean number of shoots (11.6 1.16) and shoot length (4.8 0.43 cm) per explant. A culture period longer than 8 d with TDZ resulted in the formation of fasciated or distorted shoots. The regenerated shoots rooted best on MS medium containing 1.0 μM indole-3-butyric acid (IBA). The micropropagated shoots with well developed roots were successfully established in pots containing garden soil and grown in greenhouse with 95 % survival rate. The regenerated plants were morphologically uniform and exhibited similar growth characteristics and vegetative morphology to the donor plants.