Effect of nitrogen concentrations and Fusarium oxysporum inoculation on barley growth under different Cd levels

Abstract

Nitrogen fertilization plays an essential role in plant-defense reactions against various stresses. However, its role in developing a plant's heavy-metal stress reaction in the presence of fungal inoculation is still not well understood. Therefore, a greenhouse pot experiment of barley plants was carried out to trace the impact of different concentrations of nitrogen (60 and 90 mg kg−1) and inoculation with Fusarium oxysporium on the nitrogen uptake and the yield/plant, which were affected by various cadmium levels in the soil using the 15N tracer technique. The dry weight increased significantly with increasing N concentrations and cadmium concentrations in the spiked soil, especially for fungal inoculated plants compared to than uninoculated plants. The highest N uptake was detected in the shoots and grains of fungal inoculated plants with different nitrogen levels. The cadmium content in grains tended to decrease with fungal inoculation. This holds true for all nitrogen and cadmium interactions compared to the uninoculated plants. On the other hand, cadmium detention was recorded in the roots of fungal inoculated plants that were fertilized with highest N-concentrations. The highest percentage of nitrogen in grains derived from fertilizer (Ndff%) was 24.45 and 23.30% in the pots with 90 mg N/kg soil + 10 mg Cd/kg soil + Fungi and 90 mg N/kg soil + 20 mg Cd/kg soil + Fungi, respectively, while the nitrogen use efficiency (NUE%) of the grains in the these pots were recorded as 4.3% and 4.2%, respectively.