Changes in Starch, Sugar, and Abscisic Acid Contents Associated with Second Growth in Tubers of Potato ( Solanum tuberosum L.) One-leaf Cuttings

Abstract

Summary Tuberized one-leaf cuttings of potato ( Solanum tuberosum L.) were kept under conditions inducing tuber regrowth (35 °C, leaf removed) or conditions allowing normal tuber growth (20 °C, leaf removed). The level of starch decreased substantially under conditions that induced tuber regrowth with a concomitant rise in the levels of sucrose and glucose. As a result, water was taken up and the dry matter content of the tubers decreased. Immediately after leaf removal, the level of ABA in the tubers decreased significantly in both treatments. It remained low under conditions that induced regrowth, whereas in the control treatment the level of ABA increased again. The changes in carbohydrate levels and in ABA content between the two treatments both preceded the occurrence of visible second growth, but the carbohydrate differences occurred first.