SCALED-UP PROLIFERATION AND REGENERATION OF NERINE IN LIQUID CULTURES.2. ONTOGENY OF SOMATIC EMBRYOS AND BULBLET REGENERATION

The ontogeny of somatic embryos was followed in liquid cultured Nerine tissue. Proliferating, nodular meristematic clusters were maintained in bubble bioreactors in a medium supplemented with 0.25 mu M 1-naphth alene acetic acid (NAA), 10 mu M 6-benzyladenine (BA) and 8.7 mu M Pac lobutrazol (PAC). Regeneration of plantlets from this tissue was limit ed. Omission of PAC from the medium induced proembryogenic clusters. E mbryo development and maturation were enhanced in flask cultures by su bstituting N-6-(isopentenyl) adenine (2iP) for BA and elevating the su crose concentration in the medium to 6%. High rates of embryo germinat ion occurred in a growth regulator-free, low (3%) sucrose medium. Bulb let-bearing plantlets developed on agar-solidified, auxin-supplemented media. Recurrent embryogenesis occurred in long term growth regulator -free, or high sucrose media. The potential of using the somatic embry ogenesis pathway for micropropagation of Nerines is described.