Antagonistic Action Between NaCl and CaCl 2 as Influencing the Penetration of Dye into Nitella. ∗

This paper deals with the effects of several chlorides upon the penetration of the basic dye, dahlia, into the sap of Nitella sp. The plants were placed in solutions containing .0125, .025, and .05 M NaCl, KCl, CaCl₂ or MgCl₂, respectively, and .000476 per cent dahlia. The concentration of the dye in the sap was determined colorimetrically. The control solutions consisted of distilled water and tap water.

When the external solution contained any of the chlorides used the amount of dye found in the sap was less than that found when distilled water or tap water was used. NaCl was least effective in preventing penetration of the dye, and MgCl₂ had the greatest effect. The monovalent salts were, on the whole, less effective than the bivalent salts, although there was little difference between the effects of KCl and CaCl₂.

When NaCl and CaCl₂ were used together in the most favorable proportion, namely, 2 parts of Ca to 98 parts of Na, there was some antagonism between the ions in their effect upon the penetration of the dye into the sap, but not enough to permit the dye to enter at the normal rate.

These results seem to indicate that complete antagonism is not present. It is possible that appropriate mixtures containing three or more cations might show no inhibiting effect. Whether we have here a simple effect of one cation upon the other, or whether there is also an anion effect or “salt effect” is also a question which will bear further investigation.

Complete details of this paper will be published in the near future.