Nitrogen and zinc supplements can enhance morphology and physiology traits of maize at early growth stages

Several studies emphasized the importance of zinc for better morpho-physiology in plants. The co-application of Zn can reduce N loss by increasing its uptake rates, but whether N level can affect Zn accumulation in different plant organs is not well studied. This experiment aimed to examine the impact of different levels of nitrogen and zinc on the morphology, physiology and nutrient uptake of maize, and whether different N levels would affect Zn accumulation. Two maize genotypes were grown hydroponically. Nitrogen was supplemented in two different concentrations, combined with two Zn concentrations. Zn level did not affect the shoot or the root dry weight of either genotype under optimal N level, but did under reduced N level. Reduced N level resulted in significantly higher root dry weight under both Zn concentrations in both genotypes. Significantly higher nitrogen remobilization rate was found at reduced N level in both genotypes. Optimal N level resulted in higher shoot and root N and Zn contents in both genotypes. The uptake of Zn was enhanced by optimal N compared to reduced N level, where the impact of genotypes was also observable. Reduced N level decreased both optimal and actual photochemical efficiency of photosystem II, and pigment contents of both genotypes. It could be concluded that N and Zn use efficiency is highly dependent on the genetic characteristics of maize genotypes, but optimal N supply is required for better incorporation of Zn into shoot and root tissues.