Assimilate partitioning in Pachyrhizus erosus tubers under short days

• DOI: 10.1111/j.1399-3054.1995.tb06858.x
• Publication Date: 2006-05-01T06:43:14Z
• Authors: Victor Vaillant; Lucienne Desfonta...
• Keywords: 0106 biological sciences; 0301 basic medicine; 2. Zero hunger; 03 medical and health sciences; [SDV.BV]Life Sciences [q-bio]/Vegetal Biology; [SDV.BV] Life Sciences [q-bio]/Vegetal Biology; 01 natural sciences

The distribution of 14C products in yam bean (Pachyrhizus erosus) plants was measured as a function of time after a 14CO2 pulse‐chase experiment under short‐day conditions. The 14C declined by more than 70% in leaves during the first two hours, indicating that they actively exported carbon. Tubers were strong storage sinks for carbon and accumulated more than 80% of the total incorporated 14C after a 72‐h chase. The data show that, although sucrose represented about 21% of the tuber non‐structural carbohydate, i.e. 15% of the tuber dry weight, 14C did not accumulate in sucrose but in glucose, fructose and starch. The data indicate the existence of a separate sucrose pool which is affected only very slowly by recent assimilates. As a result, recent photosynthates, temporarily stored, may contribute to the reservoir of carbon available for nitrogen fixation. The data also suggest the existence of two distinct pools of amino acids in the tuber, one utilized mostly for protein synthesis and the other probably stored in the vacuole.