Effect of Bicarbonate Ion on the Respiration of Excised Roots

Abstract

The effect of HCO3- on O2 uptake by excised roots was determined on apical cm. root sections in buffered nutrient soln. using the Warburg "direct method." Inhibition of HCO3- on O2 uptake was not related to pH. Cl-, SO4=, Ca++, and Na+ did not affect O2 consumption by excised bean roots. HCO3- reduced O2 consumption by bean roots markedly and inhibition increased with time. Roots respiration of plants susceptible to lime-induced chlorosis was reduced by HCO3- while that of roots of chlorosis resistant plants was only slightly affected. Studies with HCN and other inhibitors indicated that inhibition of respiration by HCO3" is not fully explained by a direct inhibition of the cytochrome system.