Effects of pH and Ethephon on Betacyanin Leakage from Beet Root Discs

Betacyanin leakage from beet root discs was found to increase with decreasing pH of the incubation medium. Although 10 millimolar Ca²⁺ reduced pigment leakage at pH 3.5, it was ineffective at pH 2.3. Leakage was also stimulated by 100 micrograms per milliliter (2-chloroethyl)-phosphonic acid (pH 3.1), but when the solution was neutralized, this leakage was eliminated. Bubbling C₂H₄ through a neutral medium containing beet discs had no effect on pigment leakage; it appears that the effect of Ethephon solutions on this process is a function of their low pH.