Fusion of spinach mesophyll protoplasts with carrot root parenchyma protoplasts and the effect on spinach chloroplasts

Mesophyll protoplasts of spinach (Spinacia oleracea L.) have been fused, using polyethylene glycol, with root parenchyma protoplasts of carrot (Daucus carota L.) to enable studies of spinach chloroplasts in a foreign cytoplasm. After 24 h culture, electron microscopy of the fused protoplasts showed many intact chloroplasts, but some chloroplasts were completely disrupted, showing loss of chloroplast envelope and stroma. Spinach protoplasts showed normal chloroplast structure 24 h after PEG treatment. These observations are consistent with a type of incompatibility between some spinach chloroplasts and carrot cytoplasm.