Germination of Wild Rice, Zizania aquatica, Seeds and the Activity of Alcohol Dehydrogenase in Young Seedlings

Seeds of wild rice (Zizania aquatka L.) which were stored at 3°C for c. 3 months after harvest did not germinate until portions of seed coat above the embryo region were removed. During the iirst few days following germination there was no apparent difference between seedlings germinated under normal, aerated and anaerobic conditions. After 14 days, plants maintained under well aerated conditions were the most fully developed. Unlike shoot growth, roots did not develop under reduced aeration. The activity of alcohol dehydrogenase (ADH) in extracts obtained from young Zizania seedlings was highly specific for ethanol as a substrate, for NAD as the coenzyme, and the optimum pH was c. 9.1. Enzyme activity changed with stage of growth and development, reaching maximum activity 8 days after germination. Aeration strongly inhibited ADH activity. Under anaerobic conditions the activity of ADH increased several fold over the activity of ADH extracted from shoots of seedlings maintained under normal conditions.