INDUCTION OF EMBRYO-LIKE STRUCTURES BY LIQUID CULTURE IN MULBERRY (MORUS-ALBA L)

Suspension cultures of calli derived from hypocotyl explant of Morus a lba L. var. MR(2) have produced embryo like structures. Calli were ind uced on the semisolid MS medium supplemented with 1.0 mg/l 2,4-dichlor ophenoxyacetic acid (2,4-D) and 0.5 mg/l 6-benzylaminopurine (BAP). Th ey were transferred to MS liquid medium with different concentrations (0.1-1.0 mg/l) of 2,4-D and further subcultured at weekly intervals in to fresh medium. Embryo-like structures were observed at each stage of development. Cells in the suspension culture having enriched cytoplas m with prominent nuclei, divided to form filamentous structures and co ntinuous division of these structures lead to the development of globu lar and heartshaped structures, Suspension medium containing 0.5 mg/l 2,4-D was essential to induce high frequencies of embryo like structur es while lower (0.1-0.2 mg/l) and higher (1.0 mg/l) concentrations cau sed either root or callus formation respectively. There was no further development of the heartshaped structure in the liquid medium contain ing 2,4-D.