Patterns of dry matter accumulation in soybean plant leaves are similar in both determinate and indeterminate types of soybean (Beaver et al.1985). Dry matter increases from the vegetative to the reproductive stage until a maximum value is attained, and decreases thereafter, during the rapid development of the seeds. The middle leaves show the most characteristic changes in the patterns of dry matter accumulation in blades of trifoliolate leaves. These changes are initiated by the transport of material to the developing seeds and coincide with the time of increased leaf fall, as the rate of abscission of leaves from the plants exceeds the production of new leaves (Drossopoulos et al. 1994). In the middle leaves, the rate of dry matter accumulation per trifoliolate leaf during the vegetative stage is large and leads, at the end of this stage, to level of accumulation 3.45 times higher than the initial value. During the reproductive stage, dry matter continues to accumulate although at a lesser rate.