STARCH METABOLISM DURING GROWTH AND STORAGE OF TUBERS OF 2 NEW-ZEALAND POTATO CULTIVARS

Polysaccharides, sugars, and enzymes involved in starch metabolism wer e assayed at 14-day intervals during development and the following 2 m onths of storage at 9 degrees C for two New Zealand-bred potato cultiv ars - 'Ilam Hardy' and 'Rua'. Despite changes in sugars and activities of enzymes, starch levels remained relatively constant. Glucose and s ucrose levels decreased throughout development. Enzymes involved in st arch synthesis and degradation were active throughout tuber developmen t. These observations suggest that the developing tuber may act as a d ynamic pool of sugars available to the plant. Changes in sugars and en zyme activities between sampling dates reflected variations in soil te mperature.