Changes in Carbohydrate and Phosphorus Content of Potato Tubers during Storage in Nitrogen

SUMMARY When potatoes are stored in nitrogen at low temperatures, starch decomposition, release of starch‐bound phosphorus, and accumulation of inorganic phosphorus are less than during storage in air. Although there is a complete suppression of sugar accumulation, evidence is presented that the starch removed appears as substances, probably end‐products of anaerobic glycolysis, that are volatile at the temperatures used to determine percent dry weight. The decreases in starch‐bound phosphorus are balanced by a corresponding increase in inorganic phosphorus in both air‐stored and nitrogen‐stored potatoes. The decrease in the phytic acid phosphorus in air‐stored tubers can be accounted for largely as an increase in the fraction containing phosphoproteins, nucleic acids, and phospholipids, whereas the corresponding loss of phytic acid phosphorus in nitrogen‐stored tubers appears largely in the fraction containing nucleotide coenzymes and hexose phosphates. The significance of these findings is discussed in terms of the requirements for high‐energy phosphate derived from the respiratory process and needed for biosynthesis.