Changes in free and conjugated IAA during dormancy and sprouting of potato tubers

Abstract

The time course of free and conjugated indole-3-acetic acid (IAA) concentrations was investigated in three distinct parts (eyes, subeye tissues and pith) of potato (Solanum tuberosum L. cultivar Monalisa) tubers, from the last period of tuber growth to sprouting under two different storage temperatures (3 and 23˚C). The highest levels of both free and conjugated IAA were detected in eyes, which showed a significant increase of the free hormone concentration from harvest to the end of dormancy, regardless of storage temperature. The concentration of conjugates was higher than free IAA in eyes and subeye tissues at 23˚C, while at 3˚C conjugates prevailed only in eyes. Present results suggest the involvement of IAA in the control of potato tuber dormancy.