14CO2 fixation and allocation of 14C into major biochemical fractions in different parts of Indian mustard (Brassica juncea)

14CO2 fixation and transport of 14C-photosynthates amongst different parts of Indian mustard (Brassica juncea) and the incorporation of 14C into major chemical fractions in different plant parts was studied at ripening stage. Stem and pod together contributed 70 % of the total 14C fixed by the plant. In all plant parts neutral saccharide fraction contained maximum radioactivity immediately after exposing plants to 14CO2. After 24 h, the radioactivity in this fraction declined considerably due to translocation or conversion into other fractions. Concomitantly radioactivity in lipids and pigments, residue and starch fractions increased after 24 h. The 14C allocation patterns in stem and leaves were similar. However, in pods very high radioactivity was recovered from amino and organic acid fractions indicating the presence of active phosphoenolpyruvate carboxylase in pod walls