Figure 2

Schematic representation of the main biological changes occurring in the leaves of the gln1.3 and gln1.4 mutants. On the top of the figure is shown a schematic representation of leaf N management in maize during the developmental cycle. During vegetative growth (V), N is taken up by the roots and assimilated to build up plant cellular structures (green arrow). After flowering the N accumulated in the vegetative parts of the plant is remobilized and translocated to the developing kernels. At the same time (yellow arrow), which corresponds to the grain filling period (M), about half of the N that is translocated to the developing kernels is taken up after flowering to contribute to storage protein deposition until the kernels reach maturity. During these two main phases of plant development the large arrows indicate the different biological functions that exhibit the most significant decrease (blue arrow) or increase (red arrows) in the gln1.3 and gln1.4 mutants. The physiological impact of the two mutations is indicated below the green and yellow arrows in italics, which corresponds to the two main phases of leaf N management before and after flowering.