Partitioning of ¹⁴C-photoassimllates within seeds of Phaseolus coccineus (Lam.) and Phaseolus coccineus x Phaseolus vulgaris L.

The objective of this study was to determine partitioning within seeds of ¹⁴C-photoassimilates at three stages of seed development in two Phaseolus crosses - P. coccineus Lam. selfed, and P. coccineus x P. vulgaris L. Abortion of the interspecific embryos occurred when the seed reached 10 mm seed length. When expressed as sink strength (% dpm) or sink activity (% dmp/d.wt.) there were no differences in partitioning of ¹⁴C-photoassimilates when whole seeds were analyzed. If the seed was divided into seed coat, liquid endosperm, and embryo, the sink activity of the interspecific embryo was higher than that of the embryo in the selfed seed. Therefore, abortion of these interspecific Phaselus embryos appeared not to be caused by a lack of photoassimilates.