Synthesis of asparagine from 14CO2 in wheat seedlings

Abstract

Wheat shoots were supplied with 14CO2 during a light period (6–24 h), then placed in darkness for periods up to 48 h. During the dark period labeled sugars disappeared and labeled asparagine accumulated, suggesting the conversion of sugar carbon to asparagine. Sugars produced later in the dark period were preferentially used. Asparagine was formed throughout the plant. It was translocated out of the leaf blades but not to the roots. Glutamine was formed only in leaves, and translocated to both the stem and the root. The data suggest that glutamine is more important as a translocation form of nitrogen, while asparagine serves mainly as a storage compound.14C-Asparagine was biosynthesized from 14CO2 with higher yield and specific radioactivity than has been possible by previous methods.