Kh. Muhling et B. Sattelmacher, DETERMINATION OF APOPLASTIC K+ IN INTACT LEAVES BY RATIO IMAGING OF PBFI FLUORESCENCE, Journal of Experimental Botany, 48(313), 1997, pp. 1609-1614
The tetraammonium salt of the K+ binding fluorescent dye benzofuran is
ophthalate (PBFI) was used to investigate the influence of potassium n
utrition (0.1-2.1 mol m(-3)) on apoplastic K+ in Vicia faba leaves by
means of ratio imaging. As a reference the infiltration-centrifugation
method was used. Both methods reflected the influence of K+ supply on
apoplastic K+ concentration. The abaxial leaf side revealed significa
ntly higher K+ concentrations (20-25 mol m(-3)) than the adaxial side
(5-8 mol m(-3)). Application of CCCP led to an immediate increase in a
poplastic K+ demonstrating the reliability of the PBFI method.