Influence of plant growth regulators on in vitro shoot multiplication and plantlet formation in Cassia angustifolia vahl

Abstract

An effective and improved plant regeneration system was successfully developed using shoot tip explants taken from a two years old mature plant of Cassia angustifolia. The effect of different cytokinins, [6-benzyladenine (BA), Kinetin (Kin) and thidiazuron (TDZ)] at different concentrations (0.5-10 μM) were evaluated as augmented with Murashige and Skoog (MS 1962) medium. Among all the cytokinins tested, TDZ (5.0 μM) was optimum in inducing multiple shoots as compared to BA and Kin. The rate of shoot multiplication was increased when optimal concentration (5.0 μM) of BA and Kin was tested with different concentration (0.1-1.0 μM) of Indole-3- acetic acid (IAA). Among all the combinations tested, the maximum rate of shoot multiplication was obtained on MS medium supplemented with 5.0 μM BA and 0.5 μM IAA. The number of the shoots and shoot length developed in TDZ was increased when transferred to MS medium devoid of TDZ. After every subculture, rate of the shoot multiplication and shoot length showed increment and continued even after fifth subculture without any decline rate. In vitro rooting in regenerated shoots were best obtained in half-strength MS medium supplemented with 2.0 μM indole-3- butyric acid (IBA). Plantlets with well-developed shoot and roots were successfully hardened off in earthen pots containing garden soil and grown in greenhouse with 80% survival rate.