The Permeability to Oxygen of the Periderm of the Potato Tuber

The permeability to oxygen of the periderm of the potato tuberhas been measured during its development and storage. When expressedas ml O₂, diffusing through 1 cm² periderm in 1 sec under anO₂, pressure of 1 atm, the values for freshly harvested tubersranged from a maximum of 2.4 x 10^–4 in immature tubers,to less than 0.7 x 10^–4 in tubers harvested mature someweeks after the death of the foliage. In every case, after storagefor up to 10 weeks at 10^° C, the permeabilities, as expressedabove, were less than 0.7 x 10^–4 (minimum values, c. 0.5x 10^–4 It was shown that the oxygen deficit under theperiderm was unlikely to exceed 0.03 atm during development,and the oxygen status of the developing tuber should thus beadequate for the low oxygen-affinity oxidase system (if present)to function.