Xu, X.Y., Xie, G.S., He, L., Zhang, J.J., Xu, X.L., Qian, R., Liang, G.H. and Liu, J.H. (2013) Differences in Oxidative Stress, Antioxidant Systems, and Microscopic Analysis between Regenerating Callus-Derived Protoplasts and Recalcitrant Leaf Mesophyll-Derived Protoplasts of Citrus reticulata Blanco. Plant Cell, Tissue and Organ Culture, 114, 161- 169.