Seasonal Changes of Activities of Asparagine Synthetase and Asparaginase in Relation to Asparagine Content in Sugarcane

Abstract

We studied on the seasonal changes of asparagine, aspartic acid, glutamine and glutamic acid contents and activities of asparagine and glutamine synthetases and asparaginase and glutaminase in stalks and roots of two varieties of sugarcanes, 'Chikusha' and 'N:CO 310'. The highest activity of asparagine synthetase was observed in the basal part of stalks in August, whereas that of asparaginase was observed in September. Asparagine synthetase showed the highest activity at root in June and/or July. In 'N:CO', asparagine content in the basal part of stalk continued to decrease until October, whereas that in the upper part of stalk increased in September to November. In 'Chikusha', asparagine showed the highest content in the stalk in July, and its content increased in the middle and top parts of the stalk in September to November. The best harvest time of 'Chikusha' sugarcane is considered to be in November on the basis of the highest weight and asparagine contents in stalk.