CALCULATIONS OF BIOELECTRIC POTENTIALS : VI. SOME EFFECTS OF GUAIACOL ON NITELLA.

Values have been calculated for apparent mobilities and partition coefficients in the outer non-aqueous layer of the protoplasm of Nitella. Among the alkali metals (with the exception of cesium) the order of mobilities resembles that in water and the partition coefficients (except for cesium) follow the rule of Shedlovsky and Uhlig, according to which the partition coefficient increases with the ionic radius. Taking the mobility of the chloride ion as unity, we obtain the following: lithium 2.04, sodium 2.33, potassium 8.76, rubidium 8.76, cesium 1.72, ammonium 4.05, (1/2) magnesium 20.7, and (1/2) calcium 7.52. After exposure to guaiacol these values become: lithium 5.83, sodium 7.30, potassium 8.76, rubidium 8,76, cesium 3.38, ammonium 4.91, (1/2) magnesium 20.7, and (1/2) calcium 14.46. The partition coefficients of the chlorides are as follows, when that of potassium chloride is taken as unity: lithium 0.0133, sodium 0.0263, rubidium 1.0, cesium 0.0152, ammonium 0.0182, magnesium 0.0017, and calcium 0.02. These are raised by guaiacol to the following: lithium 0.149, sodium 0.426, rubidium 1.0, cesium 0.82, ammonium 0.935, magnesium 0.0263, and calcium 0.323 (that of potassium is not changed). The effect of guaiacol on the mobilities of the sodium and potassium ions resembles that seen in Halicystis but differs from that found in Valonia where guaiacol increases the mobility of the sodium ion but decreases that of the potassium ion.