Studies in the respiratory and carbohydrate metabolism of plant tissues I. Experimental studies of the formation of carbon dioxide, lactic acid and other products in potato tubers under anaerobic conditions

Abstract

Using mature potatoes of low sugar content, held at 10 degrees C both in air and in nitrogen, the following metabolic changes were determined. The $\text{CO}_{2}$ production in nitrogen showed a complex form, the initial phase consisting of a slight increase, followed by a marked fall to a minimal rate after from 6 to 9 days. The sucrose and hexose content changed little in air, but in nitrogen sucrose decreased markedly, and the hexoses were either stable or increased. While lactic acid accumulated progressively under anaerobic conditions, the content of alcohol did not begin to increase until after about 7 days. Subsequently the rate of accumulation of lactic acid decreased, and that of alcohol increased. During the period of rising lactic acid, an approximately equivalent increase occurred in a non-sugar, non-lactic, alcohol-soluble fraction. Lactic acid was isolated as the zinc salt; it was present mainly as the L-isomer. The experimental data are analyzed in part II of this communication (p. 385).