Somatic embryogenesis and plant regeneration from suspension cultures of Sapindus trifoliatus

A procedure for plant regeneration from cell suspension cultures through somatic embryogenesis is described for Sapindus trifoliatus, a commercially and medicinally important tree. Callus was induced from leaf disc on agar-solidified MS medium with 5.0 mg l⁻¹ 2, 4-D and 0.01 mg l⁻¹ Kin. Embryogenic cell suspension cultures were established by placing leaf-derived friable calli in PGR-free full-strength MS liquid medium with 3% sucrose. The growth of cell suspension culture was significantly affected by the strength of the MS mineral solution and L-glutamine. Plating of the suspension on semisolid MS medium resulted in the formation of globular structures. These embryogenic globular structures differentiated into secondary globular structures or somatic embryos on a semisolid MS medium. The differentiation of globular structures and different stages of somatic embryos (from globular to cotyledonary) was enhanced by the addition of 200 mg l⁻¹ L-glutamine in the medium. Sucrose at relatively high concentrations (5%) or ABA (0.01 mg l⁻¹) promoted somatic embryo maturation. The highest percentage (about 90%) of germination of somatic embryo and plantlet conversion was achieved on a half-strength MS medium containing 2% sucrose. The plants were hardened and established in soil with a 90% survival rate