Metabolic Responses to Contrasting Levels of N Fertilization during Ear Leaf Transition from Assimilation to Remobilization at Grain Filling in Maize

MAIZE grain yield is shaped by source-sink relationships during filling. Such relations are driven complex metabolic changes, responsive to N availability and not fully understood. Here, the impact of limited sufficient fertilization on interconversions in ear leaf a new maize field-grown hybrid (Tzi8 × Mo17) its critical transition from assimilation remobilization were chronologically investigated at 0, 5, 10, 15, 20 days after pollination. N-deficient plants produced 43% less 13% biomass however, they had 51% higher root dry weight Root/Shoot ratio anthesis. The low N-induced reduction accumulation was associated with earlier chlorophyll degradation overall decrease chlorophyll, total soluble proteins, carbon (C: sucrose & sugars), assimilates (leaf N, nitrate, ammonia amino acids). In contrast, accumulated 18% more starch 24 % flavonoids than N-sufficient such responses sink limitation. also significantly activities remobilizing (asparaginase protease) but lower assimilating (nitrate reductase glutamine synthetase) enzymes compared plants. Glutamate aspartate followed branched acids dominated pool under both conditions. Altogether, induction represent N-specific whereas rest depict common between adequate