Tuberization in Potato at High Temperatures: interaction between Shoot and Root Temperatures

Tuber formation in intact potato plants (Solanum tuberosum L.cv. Sebago) was reduced by high shoot or root temperatures andstrongly inhibited when both were high. When both the shootand root temperatures were high, disbudding strongly promotedtuberization. There was a smaller increase with warm roots andcool shoots, but no response with warm shoots and cool roots.When both the shoots and roots were cool, disbudding reducedtuberization. Exogenous GA₃, effectively substituted for thebuds at high temperatures, completely preventing tuberization.In apical cuttings, removal of the terminal bud, but not theroots, reduced the inhibitory effects of high temperatures ontuberization. The experiment indicates that tuber productionmay be controlled by at least three factors: a promoter, whichis not assimilate, produced by the buds at cool temperatures;an inhibitor, derived from the buds, but dependent on warm roottemperatures for its formation; and a second inhibitor derivedfrom the mature leaves and produced in response to warm shoottemperatures. Solanum tuberosumL, potato, tuberization, temperature, disbudding, gibberellic acid