Differential pattern of 14C-incorporation into soluble and insoluble fractions in leaves of C3 and C4 plants

A distinct pattern of 14C incorporation into the soluble and insoluble fractions, characteristic to the C3 and C4 plants was observed during long term photosynthesis. C4 plants showed an average ratio of 4.85 in the amount of radiocarbon recovered in the soluble to insoluble fractions, while in the C3 plants the corresponding ratio was 1.26. This pattern was well matched with characteristic differences in the leaf anatomy of the two plant types. Photosynthetic rate and translocation of assimilated 14C were consistently higher in C4 plants than in C3 plants. From the present study it is thought that the C3 plants are equally efficient in the conversion of photosynthetically fixed carbon into insoluble compounds accounting for major dry matter production. (auth.)