STRATEGIES FOR PROMOTING DIVISION OF CULTURED PLANT-PROTOPLASTS - SYNERGISTIC BENEFICIAL-EFFECTS OF HEMOGLOBIN (ERYTHROGEN) AND PLURONIC F-68

Novel approaches, involving supplementation of aqueous culture medium with haemoglobin solution (Erythrogen), in the presence or absence of the copolymer surfactant, Pluronic F-68, have been evaluated to facili tate cellular oxygen availability to promote mitotic division. Cell-su spension-derived protoplasts of albino Petunia hybrida cv. Comanche we re cultured for up to 45 days in KM8P medium containing 1:50-1:500 (vo l:vol) Erythrogen. The mean initial protoplast plating efficiency afte r 9 days with 1:50 Erythrogen (18.5%) was significantly greater (P<0.0 5) than in untreated controls (11.3%). Supplementation of culture medi um with 1:50 Erythrogen, together with 0.01% (wt/vol) Pluronic F-68, i ncreased the mean plating efficiency after 9 days (24.4%) by 92% (P<0. 05) over the control (12.7%). These treatments also produced increases in biomass of protoplast-derived cells up to 2.5-fold greater than co ntrol (P<0.01) over 80 days. Gassing the medium, containing 1:50 Eryth rogen, with carbon monoxide abolished the increase in plating efficien cy. There was no additional benefit of gassing Erythrogen-supplemented medium with 100% oxygen. The synergistic, beneficial effect of Erythr ogen and Pluronic F-68 on protoplast division has implications for pla nt biotechnology utilising protoplasts.