Monocarpic plants such as rice and wheat need to initiate the whole plant senescence before their pre-stored assimilates can be remobilized for the grain filling. However, plant senescence and photosynthesis are a pair of trade-off processes. How to coordinate plant senescence, photosynthesis, and remobilization of assimilates is a long-term unsolved problem in cereals. Solving this problem would have great significance in not only understanding the mechanism of the remobilization of assimilates to grain an...