D vs a Graph
 

Fig. 5. Lily pollen proton flux measured in two concentrations of MES, pH 6.15.   A. Raw ÁV differences measured at positions marked by squares.   B. Computed diffusional flux and facilitated flux in 60 ÁM MES.   C. Computed diffusional flux and facilitated flux in 300 ÁM MES.  The probe is sensative to more global proton flux in the lower concentration MES.  Noise becomes a larger contributor to total flux in the higher concentration MES because the measureable information (ÁV difference over 10 Ám excursion) becomes a smaller proportion of total proton flux.  The media used to examine the pollen tube growth contained 1.0 mM KCl, 0.05 mM CaCl2, 1.6 mM H3BO3, x ÁM MES and 5% sucrose [1].

 
(Click for higher resolution fig)