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

Abstract

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