The effect of the concentrations of carbon dioxide and oxygen in the storage atmosphere upon the sprouting of potatoes at 10°C

Abstract

1. Sprout growth is inhibited at 10°C by a concentration of 15 per cent of carbon dioxide in the storage atmosphere, decreased by lower concentrations, and stimulated by still lower concentrations. The optimum concentration for growth need not necessarily be the same in all cases; but appears to be about 2–4 per cent, which would give a concentration in the cell sap of some 0.04–0.05 ml carbon dioxide per ml sap. 2. In agreement with reports by other workers, sprout growth was found to be stimulated by reducing the concentration of oxygen in the storage atmosphere to 5 per cent, which would give a concentration of oxygen in the cell sap of about 0.006 ml oxygen per ml sap. 3. A reduced oxygen tension causes augmented growth either by means of an increase in the number of sprouts or in the number of cells in individual sprouts. A raised carbon dioxide tension causes an increase in the number of cells in the sprouts and also marked cell elongation. 4. Over the range 10–25 C the effect of temperature upon respiration and upon the solubility of gases — and hence upon the concentrations in the cell sap of dissolved oxygen and, more particularly, carbon dioxide —could be an important factor contributing to the effect of temperature upon sprout growth. In some cases the increased sprout growth after some time at a higher temperature may be no more than would be expected as a result of the increased carbon dioxide in solution. 5. Discussion of the results in the light of other work suggests several mechanisms through which changes in the carbon dioxide or oxygen concentrations may influence sprout growth. Such suggestions must be very tentative pending more detailed investigation of the systems involved.