Ohnishi, A., Fukada-Tanaka, S., Hoshino, A., Takada, J., Inagaki, Y. and Iida, S. (2005) Characterization of a Novel Na+/H+ Antiporter Gene InNHX2 and Comparison of InNHX2 with InNHX1, Which Is Responsible for Blue Flower Coloration by Increasing the Vacuolar pH in the Japanese Morning Glory. Plant and Cell Physiology, 46, 259-267.