An efficient and reproducible protocol for in vitro multiplication of Bauhinia tomentosa L. was developed. Multiple shoots were regenerated from cotyledonary node and stem nodal segments excised from in vitro raised seedlings on Murashige and Skoog (MS) medium supplemented with different concentrations (0.1, 0.3, 0.5, 0.8 and 1.0 μM) of thidiazuron (TDZ). The maximum response (62.6%) was recorded on MS medium amended with 0.8 μM TDZ. A long exposure to TDZ for 8 weeks showed abnormalities such as fasciation and compact shoots formation. To avoid adverse effects of prolonged exposure to TDZ in long-term establishment, the culture were transferred to TDZ free MS medium for further multiplication and elongation. The highest number of shoots and shoot length were recorded at the end of fourth subculture passage. Ex vitro rooting was achieved when the basal cut end of regenerated shoots were dipped in 200 μM indole-3-butyric acid (IBA) for half an hour followed by their transplantation in plastic pots filled with sterile Soilrite™ where 60% plantlets grew well and all expressed normal development.
Rapid differentiation of multiple shoots was observed in 94% of nodal explants of one year old Nyctanthes arbor-tristis L. plants. Shoot bud induction and multiplication took place on Murashige and Skoog (MS) medium supplemented with two cytokinins, i.e. Benzyladenine (BA) or Kinetin (Kn) either alone or in combination with different auxins, indole-3-butyric acid (IBA), indole-3-acetic acid (IAA) or α-naphthalene acetic acid (NAA). Between different media, pH levels and growth regulators tried, the optimum condition for maximum regenerative response was obtained on MS + Kn (2.5 μM) + N AA (0.5 μM) media at 5.8 pH, forming cultures with 23.26 ± 0.89 number of shoots and 6.36 ± 0.80 cm shoot length after 8 weeks of culture. Histological sections confirmed the formation of multiple buds from nodal explants. Rooting was achieved ex vitro by dipping the basal ends of microshoots in 200 μM IBA for 30 min followed by their transplantation in sterile soilrite. The plantlets with well-developed shoot and root system were successfully established in garden soil and grown outside in a greenhouse with a 80% survival rate.
Authors:I. Siddique, N. Abdullwahab Bukhari, K. Perveen, I. Siddiqui, and M. Anis
An in vitro propagation system for Cassia angustifolia Vahl. has been developed. Due to the presence of sennosides, the demand of this plant has increased manyfold in global market. Multiple shoots were induced by culturing nodal explants excised from mature plants on a liquid Murashige and Skoog  medium supplemented with 5–100 μM of thidiazuron (TDZ) for different treatment duration (4, 8, 12 and 16 d). The optimal level of TDZ supplemented to the culture medium was 75 μM for 12 d induction period followed by subculturing in MS medium devoid of TDZ as it produced maximum regeneration frequency (87%), mean number of shoots (9.6 ± 0.33) and shoot length (4.4 ± 0.46 cm) per explant. A culture period longer than 12 d with TDZ resulted in the formation of fasciated or distorted shoots. Ex vitro rooting was achieved when the basal cut end of regenerated shoots was dipped in 200 μM indole-3-butyric acid (IBA) for half an hour followed by their transplantation in plastic pots filled with sterile soilrite where 85% plantlets grew well and all exhibited normal development. The present findings describe an efficient and rapid plant regeneration protocol that can further be used for genetic transformation studies.