XVI International Botanical Congess
Acidification of cytoplasm takes place during Pi uptake due to proton symport. This in turn activates biochemical pH-stat (Sakano et al. PCP, 39:615, 1998). Sakano (PCP, 39:467, 1998) pointed out the involvement of the alternative pathway respiration to it. In the present study, we examined effect of nPG (inhibitor of alternative pathway respiration) and KCN (inhibitor of cytochrome pathway respiration) on Pi uptake and cytoplasmic pH regulation in cultured Catharanthus roseus cells using 31P-NMR spectroscopy.The rate of Pi uptake did not change after application of nPG. On the other hand, KCN decreased Pi uptake and caused cytoplasmic acidification, and successive addition of nPG brought about further acidification of the cytoplasm.