Influence of the phytohormones on the in-vitro regeneration in Senna alata (Linn)

Plants growth regulators, especially auxins and cytokinins are critical for in-vitro plant regeneration. The effect of plant growth regulators on the in-vitro propagation of Senna alata (Linn) was investigated. Mature seeds were collected from the medicinal garden of National Centre for Genetic Resources and Biotechnology (NACGRAB), Ibadan (Lat.7022I N and long.3050I E). Seeds of the species were inoculated into Murashige and Skoog (MS) media only. Proliferated shoots were excised; one shoot-tip cutting per test-tube was inoculated into MS supplemented with benzylaminopurine (BAP) + naphthalene acetic acid (NAA) at concentrations of 0.05+0.01, 0.075+0.01, 0.10+0.01, 0.125+0.01 and 0.15+0.01 mg/l; kinetine (KIN) +NAA (0.05+0.01, 0.075+0.01, 0.10+0.01, 0.125+0.01 and 0.15+0.01 mg/l) and a control (MS only). Within 14 weeks of culture, elongation of shoots was observed. There were significant differences (P≤0.05) in all seedling parameters assessed; the highest number of shoots/plantlet at concentration 4.00 ± 0.00 was obtained in MS media that had 0.05 mg/l BAP and 0.01 mg/l NAA, 0.075 mg/l BAP and 0.01 mg/l NAA. The highest values of 4.05 ± 0.46 cm and 3.50 ± 0.22 for shoot length and number of nodes per sprouted shoot respectively were obtained in MS media that had 0.05 mg/l BAP and 0.01 mg/l NAA; the highest number of leaves of 13.90 ± 0.41 was obtained in MS media that had 0.05 mg/l KIN and 0.01 mg/l NAA. MS media that had 0.15 mg/l KIN and 0.01 mg/l NAA gave the highest values of 4.80 ± 0.51 and 2.96 ± 0.05 cm for number and length of roots respectively. Control treatment gave the lowest values for all parameters assessed. Eighty percent of transplanted plantlets survived and grew successfully on the field. Therefore, it is recommended that Senna alata be propagated in MS media supplemented with low concentration of BAP (0.05 mg/l) and relatively high concentration of KIN (0.15 mg/l); and 0.01 mg/l of NAA for optimum growth.