Combining P and Zn fertilization to enhance yield, grain Zn availability and protein profile in maize grown on Mediterranean soils

Alkaline soils such as those found in some Mediterranean areas typically have a low phosphorus (P) and zinc (Zn) phytoavailability that detracts from plant growth and yield. We examined the effects of P and Zn fertilization individually and in combination on growth, yield and grain protein content in maize grown in pots filled with three Mediterranean soils. P and Zn translocation was impaired, and yield reduced by 8–85%, in plants treated with Zn or P alone. In contrast, joint fertilization with P and Zn enhanced translocation to grain and nutrient use efficiency, thereby increasing plant growth, yield (31–121%) and grain Zn availability. Fertilization with P or Zn also influenced the abundance of specific proteins affecting grain quality (viz., storage, lys-rich and cell wall proteins), which were more abundant in mature grains from plants fertilized with Zn alone and, to a lesser extent, P + Zn.