FIG. 3.

Effect of KOCN on HCO₃⁻ and CO₂ transport in Synechococcus sp. strain UTEX 625 cells grown in standing culture. The initial rate (20 s) of HCO₃⁻ transport was measured (method C) at substrate concentrations of 50 μM (•) and 250 μM (○) in pH 8 buffer to determine the effect of increasing [KOCN] on Na⁺-independent HCO₃⁻ transport in the presence of 100 μM NaCl (A) or Na⁺-dependent HCO₃⁻ transport in the presence 30 mM NaCl (B). (C) The initial rate (10 s) of CO₂ transport (▪) was measured at 10 μM in the presence of 100 μM NaCl (method D). Also shown is the effect of KOCN on CO₂ transport in cells grown under high-C_i conditions(⋄). The data are the average of six determinations ± standard deviations.