Abstract
Yacon (Polymnia sonchifolia), a perennial plant of the family Compositae, accumulates a large amount of fructans with relatively low DP in the tubers and tuberous roots. We investigated the seasonal growth and fluctuations of the water soluble carbohydrate content in each part of the yacon during the growth and dormancy periods. The most vigorous growth of the aerial parts and tuberous roots was observed in September. The tubers swelled rapidly in November. Thereafter the leaves and stems completely died due to the frost in the middle of December. Fructans were the predominant water-soluble carbohydrate in the tubers and tuberous roots throughout the growth period. The amount of fructans in the tubers increased rapidly in November and remained constant during the dormancy. While the amount of fructans in the tuberous roots increased dramatically in September, there was a significant decrease in fructan content during the period between October and March.
