With greening of soybean embryos during seed ripening, increased granal stacking directly correlates with decreasing chlorophyll a/b ratios. However, the intergranal fret system that is normally observed in chloroplasts is minimally developed during embryogenesis. Transitions in chloroplast development were correlated with coincident transitions in cellular ultrastructure. Levels of chlorophyll a/b binding protein mRNAs decreased prior to chloroplast dedifferentiation to eoplast during seed maturation. This suggests that the availability of chlorophyll a/b binding proteins is essential for maintenance of thylakoid appression and stacking against derivative processes.