Figure 11.

A proposed model illustrating the link between melatonin and improved tolerance of plants to Fe deficiency. The increased melatonin level induces the increment of the polyamine content, with the subsequent induction of NO accumulation. The enhancement of the NO signal then activates Fe deficiency responses and increases the remobilization cell wall Fe, which results in the increased soluble Fe in response to the low Fe supply. Dashed arrows indicate regulatory pathways. Red upright arrows denote increases in content or effects.