AN IN VITRO PLANT REGENERATION SYSTEM through callus induced from cotyledonary explants of Gleditsia caspica was established. Calli were induced on Murashige and Skoog (MS) medium containing 3% sucrose, 0.8% agar, and different concentrations of indole-3-butryc acid (IBA), naphthalene acetic acid (NAA) and 2,4-dichlorophenoxyacetc acid (2,4-D) alone, or in combination with 4.4 μM benzyl adenine (BA). The highest frequency of compact, nodular, and regenerative callus formation was obtained on MS medium supplemented with either 13.3 μM 2,4-D alone, or in combination with 4.4 μM BA. Shoot regeneration successfully occurred when calli were transferred onto MS medium supplemented with BA alone (2.2, 4.4, 8.8, or 17.7 μM), or in combination with 2,4- D (2.3 μM). The highest shoot regeneration was achieved on MS medium containing 8.8 μM BA alone, with an average of 13.7 microshoots per callus. To further elongation of the formed shoots, these were transferred to MS medium supplemented with gibberellic acid (GA3) (1.4, 2.9, 5.4, or 8.2 μM) alone or in combination with 4.4 μM BA. The highest elongation growth was recorded on MS medium containing 8.2 μM GA3 plus 4.4 μM BA. To induce root formation, the regenerated shoots were transferred onto half-strength MS medium containing different concentrations of IBA alone, or in combination with kinetin (KIN). Maximum rooting (93.8%) was obtained on medium containing 9.8 μM IBA along with 0.92 μM KIN. After acclimatization, the regenerated plants were successfully transferred to soil under greenhouse conditions.
