The influence of sodium and potassium ions on the uptake of phosphate by Ankistrodesmus braunii

摘要: The uptake of phosphate as influenced by sodium and potassium ions was investigated in the light dark. It found to be a function external concentration. At low concentration (up 10(-5) mol/l) presence Na(+) is quickly absorbed hence limiting factor for further labelling. In K(+) constant over long period.The enhancement also when P raised up 10(-4) mol/l. Then gross proceeds six hours, with greatest Na(+)-dependent increase occurring label TCA-insoluble fraction (Pu).The strongly dependent on pH reaction mixture. it highest between 5.6 7. As parallels dissociation curve dihydrogen form H2PO 4 (-) , Na(+)-enhancement optimal alkaline range (pH 8).On basis comparison pH-dependence dependence analysed method enzyme kinetics, suggested that Ankistrodesmus metabolically transports but not HPO (=) . Moreover, concluded from absence stimulation weak inhibition DCMU or CCCP at P-concentrations diffusion uptake. Only higher concentrations an active measured.Furthermore observed Na(+)-stimulation (32)P-labelling TCA-soluble insoluble compounds inside cell indirect depends only action first transport site plasmalemma.