Haemoglobin (Erythrogen) enhanced microcallus formation from protoplasts of Indica rice (Oryza sativa L.)

The beneficial effects have been studied of supplementing culture medium with 1:100-1:500 (v:v) of a commercial haemoglobin solution (Erythrogen) on the mitotic division of cell suspension-derived protoplasts of Indica rices (Oryza sativa L.). Protoplasts were cultured in liquid medium, at densities of 1.5 x 10(6) or 2.5 x 10(6) ml(-1), on nitrocellulose membranes overlaying a semi-solidified medium layer that was supplemented with both Erythrogen and nurse cells of Lolium multiflorum. The mean final plating efficiencies (FPEs) of rice cv. BR26 protoplasts cultured with 1:200 (v:v) Erythrogen, at 1.5 x 10(6) ml(-1) (0.018+/-0.003%; n = 8) and 2.5 x 10(6) ml(-1) (0.016+/-0.002%; n = 8), were both significantly (P < 0.05) greater than controls lacking Erythrogen (0.0058+/-0.002%; n = 8 and 0.0041+/-0.001%; n = 8, respectively). Similarly, the mean FPEs of cv. Bini protoplasts cultured with 1:200 (v:v) Erythrogen at 1.5 x 10(6) ml(-1) (0.012+/-0.003%; n = 6) and 2.5 x 10(6) ml(-1) (0.017+/-0.001%; n = 6) were also significantly (P < 0.05) greater than their respective controls (0.003+/-0.001%, n = 6 and 0.002+/-0.001%, n = 6). In contrast, supplementation with 1:100 or 1:500 (v:v) Erythrogen did not lead to sustained mitotic division and microcallus formation in both rice cultivars.