Photosynthetic Potential and Accumulation of Assimilates in the Developing Chloroembryos of Cyamopsis tetragonoloba (L.) Taub.

The photosynthetic potential of leaves and chloroembryos of Cyamopsis tetragonoloba (L.) Taub as measured by (14)C-bicarbonate fixation, Hill activity, and in vivo fluorescence transients is compared. On a chlorophyll basis, dark fixation of NaH(14)CO(3) in chloroembryos was 1.5 times higher than that of the leaf, whereas carbon fixation under illumination was threefold higher in the leaf than in the embryos. Rates of O(2) evolution were four times more in embryo than in leaf chloroplasts. Shading of developing fruits on the day of anthesis for 10 days induced a 65% reduction in dry matter accumulation in the etiolated embryos, as compared to the normal green embryos of the same fruit half covered by a transparent Polythene sheet. The reduction in dry weight, size of the embryos, and levels of assimilates after shading the developing fruits may be ascribed to partial autotrophy of the chloroembryos.