The Stem as a Temporary Sink before Tuberization in Helianthus tuberosus L.

The growth of individual Helianthus tuberosus (Jerusalem Artichoke)plants, and that of their component parts, was measured overone growing season of 33 weeks. The stem served as a temporarysink for assimilates before tuberization began and during thisperiod constituted up to 65 per cent of the total dry weightof the plant. Greatest tuber growth occurred when the leaveswere senescing rapidly and it was sustained by transfer of drymatter from the stem. The relationship of this growth patternto tuber and stem metabolism and its possible hormonal controlis discussed.