Manganese, iron and copper contents in leaves of maize plants (<i>Zea mays</i> L.) grown with different boron and zinc micronutrients

Abstract

Micronutrients such as boron (B), copper (Cu), iron (Fe), manganese (Mn) and zinc (Zn) play important physiological roles in humans and animals. Zn and B are the micronutrients most often deficient in maize, in Iran. A completely randomized factorial block design experiment was carried out at Fars province of Iran during the growing season in 2009 to evaluate the effects of Zn (0, 8, 16 and 24 kg ha⁻¹ Zn added to the soil and Zn foliar spray at 0.5 weight percent of zinc sulfate) and B (0, 3 and 6 kg ha⁻¹ B added to the soil and B foliar spray at 0.3 weight percent of boric acid) fertilizers on Fe, Mn and Cu concentrations in the maize leaf. The results indicate that the use of B and Zn, by spraying, increased leaf Fe content. The presence of a high amount of B in the soil, and also Zn foliar spray, assisted the increase of Fe concentration in the leaf. In fact, there were synergisms between Zn and Fe as well as B and Fe. Reduction in the leaf concentration of Mn by B application may be due to the dilution effect or the antagonistic relationship between B and Mn. The presence of a high amount of B in the soil and the spraying of B prevented the increase of the leaf Mn content, by Zn application. An antagonism was seen between Zn and Mn, in that a high amount of Zn in the soil resulted in the decrease of the leaf Mn content.

Key words: Concentration, interaction, antagonism, synergism, deficiency.