Haemoglobin-enhanced mitotic division in cultured protoplasts.

Protoplasts from cell suspensions of albino Petunia hybrida cv. Comanche were cultured for 9 days in nutrient medium containing Erythrogen, a purified bovine haemoglobin solution (supplied at 10% w/v) at 1:50-1:500 (v/v). In some assessments, the non-ionic surfactant Pluronic F-68 (Poloxamer 188), was also added to the culture medium at 0.01-1.0% (w/v). Erythrogen at 1:50 (v/v) increased the mean initial protoplast plating efficiency (IPE; 18.5 +/- 0.8%, n = 5 throughout) by 64% (P < 0.001) above that of controls (11.3 +/- 0.4%). Supplementation of medium with 1:50 (v:v) Erythrogen and 0.01% (w/v) Pluronic F-68, increased the mean IPE (24.4 +/- 1.4%) by 92% (P < 0.001) over control (12.7 +/- 1.1%). Similar results were obtained for mesophyll protoplasts of Passiflora suberosa, with 1:50 and 1:100 (v/v) Erythrogen increasing the mean IPEs to 87% and 93% respectively, over controls. This beneficial and synergistic effect of Erythrogen with Pluronic F-68, on mitotic division of cultured Petunia and Passiflora protoplasts, should also facilitate the culture of isolated protoplasts and cells of other, agronomically-important, species.