SOMATIC EMBRYOGENESIS AND PLANT REGENERATION FROM IMMATURE EMBRYO COTYLEDONS OF SYRINGA RETICULATA BLUME VAR. MANDSHURICA HARA

A somatic embryogenesis and plant regeneration protocol was established for Syringa reticulata Blume var. mandshurica Hara from immature embryo cotyledon explants. Somatic embryos (SEs) were induced on half-strength Murashige and Skoog medium supplemented with 400 mg l(-1) casein hydrolysate (CH) and different concentrations of sucrose (30, 50, and 70 g l(-1)), NAA (0, 5.37, 8.05, and 10.74 mu M), and BA (0 and 2.22 mu M). Fifty-four percent of explants produced SEs and about seven SEs were induced per explant on medium supplemented with 70 g l(-1) sucrose, 10.74 mu M NAA, and 2.22 mu M BA. Over 80% of mature SEs germinated on half-strength MS medium supplemented with 50 g l(-1) sucrose and 0.05 mu M NAA. Histological observation of SEs showed similar developmental processes to those of zygotic embryos, with globular, heart, torpedo, and cotyledon stages. Moreover, the gradual disappearance of the suspensor was also observed after the late-globular stage; the suspensor disappeared completely after the heart stage.