Hemoglobin (Erythrogen(TM))-enhanced mitotic division and plant regeneration from cultured rice protoplasts (Oryza sativa L.)

Supplementation of culture medium with hemoglobin solution (Erythrogen(TM)) promoted mitotic division, cell colony formation, and plant regeneration from rice (Oryza sativa L. cv. Taipei 309) protoplasts. The mean (+/- s.e.m., n = 5) final protoplast plating efficiency (FPE) at 28 days following exposure to 1:50 (v:v) Erythrogen(TM) (0.55 +/- 0.06%) was significantly greater (P < 0.01) than in untreated controls (0.26 +/- 0.02%). A similar, but less pronounced effect (P < 0.01) also occurred with 1:100 (v:v) (PE 0.53 +/- 0.04%) and 1:500 (v:v) (PE 0.46 +/- 0.05%) Erythrogen(TM), respectively. In contrast, there was no corresponding increase in plating efficiency with Erythrogen(TM) at 1:1,000 (v:v). These beneficial effects were sustained throughout culture. This leads to a 44% increase (P < 0.01) in protoplast-derived calli producing shoots compared to controls. Cytological analyses confirmed the diploid status of plants regenerated from Erythrogen(TM)-treated and control protoplasts. (C) 1997 Elsevier Science Inc.