Elevated ozone level affects micronutrients bioavailability in soil and their concentrations in wheat tissues

Abstract

To investigate the bioavailability of essential micronutrients (Fe, Mn, Cu, Zn) in soil-plant system, sequential scheme of weak acid soluble (WAS), reducible (RED) and oxidizable (OXI) fractions was used to evaluate the bioavailability of micronutrients in different soil depths. The results revealed that at the tillering stage elevated O3 concentration significantly increased WAS-Fe at 0-5 cm and 10-15 cm soils by 69.11% and 59.72%, respectively. At the ripening stage, both WAS-Cu and RED-Cu were significantly increased in elevated O3 treatment compared to control, while WAS-Mn only showed significant in 0-5 cm soil. In bulk soil, WAS-Zn and RED-Zn concentrations were generally greater than those in control, which was more evident at 10-15 cm soil. Besides, O3 decreased the whole plant biomass by 14.63% and increased the root to shoot ratio. Elevated O3 significantly increased grain Fe, Mn and Cu concentrations by 9.37, 36.68 and 48.18%, respectively, while it decreased Zn by 17.09%. It can be inferred that altered micronutrients bioavailability in soil and nutrients uptake in plants are likely associated with the changed soil chemical properties and plant physiology in response to the rising O3 level.