ABSTRACT
This chapter focuses on the seed as the sink and photosynthesis and remobilization as the source during reproductive growth and the most contributions pertaining to this aspect of soybean physiological processes. The life cycle of the soybean plant consists of three phases, vegetative growth, flowering and pod set, and seed filling. The production of yield by soybean can be analyzed by considering the components of yield—seeds per square meter and weight per seed. Source activity can be expressed by many parts of a plant. For example, nodules are a major source of N during much of the life cycle of a soybean plant, and roots are sources of mineral nutrients and hormones. During vegetative growth, prior to flowering, the primary sinks for assimilate are the newly developed leaves, roots, and nodules. Development of the individual seed begins before anthesis as axillary buds begin to develop into flowers.
