Abstract
Suspension-cultured Bruguiera sexangulacells were grown in NaCl solutions as high as 200 mM (Kura-Hotta et al. 2001). When cell were cultured in 150 mM NaCl increased respiration was observed and this was accompanied by a decrease in fructose-6-P (F6P) and increase in fructose-1,6-bisP, indicating activation of ATP-dependent phosphofructokinase (PFK) and/or pyrophosphate: F6P phosphotransferase (PFP). Partially purified activities of both PFK and PFP were stimulated by NaCl (in vitro). The apparent Km value of PFK for F6P was 1.1 mM. In the presence of 150 mM NaCl the Vmax/Km value increased more than 2-fold. Higher concentrations of ATP inhibited the PFK activity, but NaCl completely counteracted this inhibition. The mangrove PFP activity required fructose-2,6-bisP. Increases in the activities of these key glycolytic enzymes by salt seems to be one of the mechanisms facilitating salt tolerance of mangrove cells. Kura-Hotta et al. Plant Cell Environ. 24:1105 (2001)
