Source and Sink Relation

Numerous strategies have been developed to genetically enhance either source or sink strength independently to improve crop yield. However, many of these efforts have yielded limited success due to the intricate and dynamic interplay between source and sink organs. This chapter provides a comprehensive summary of recent advances in understanding source–sink interactions. It begins by defining key concepts such as source, sink, and flow, followed by an in-depth examination of the physiological and molecular mechanisms that regulate source–sink interactions. Emphasis is placed on the transporters and signalling molecules that facilitate nutrient allocation between sources and sinks. Finally, this chapter discusses the crucial role of balanced source–sink relationships in enhancing crop productivity and identifies key unresolved questions to guide future research.