Use of Symbiotic Fungi to Reduce the Phytotoxic Effect of DCD Nitrification Inhibitors in Lettuce

Abstract

Nitrification inhibitors are commonly used to prevent nitrate leaching. However, the use of nitrification inhibitors is not free of side-effects. Some may be absorbed by the plant and cause phytotoxicity or even affect the food chain. Therefore, a solution that limits the absorption of nitrification inhibitors and its accumulation by the plant may mitigate health and environmental issues potentially associated with high levels of nitrification inhibitors. This solution may relay in the modulation of the plant’s metabolism through the interaction with specific fungal partners. This work tested the hypothesis that the symbiotic interaction between fungi and plant roots can reduce the destructive effects of the nitrification inhibitor Dicyandiamide (DCD) in plants by reducing the uptake of nitrification inhibitors. A greenhouse experiment was conducted, using a complete randomized block design, to test the effect of symbiotic fungi (plants inoculated with Piriformospora indica, Glomus etunicatum, and Glomus mosseae and noninoculated) on the phytotoxicity of DCD applied at four concentrations (0, 5, 50, and 100 mg kg−1 soil). Latuca sativa, cultivar Siyahoo, was selected for this experiment due to its economic value all over the world. The use of high DCD concentrations (100 mg kg−1 soil) affected the leaf chlorophyll content and plant growth in a manner that was significantly mitigated by the symbiosis of the plant with the fungal partner. These results highlight the benefits of using symbiotic fungal inoculants as plant protectors against the phytotoxic effects of DCD.

A method to mitigating toxicity high concentrations of 1, 2, 4 Triazole (a nitrification inhibitor) in plant with use of the root symbiotic fungi

“…A study that describes the symptoms of TZ in plants has not been done so far. But the toxicity of NIs such as DCD including leaf chlorosis in clover (Macadam et al, 2003), lettuce (Padash et al, 2022) and 3,4-Dimethylpyrazole phosphate in clover have also been reported.…”

“…It seems that the decrease in chlorophyll concentration is due to the effect of chlorophyllase, peroxidase and phenolic compounds and as a result of chlorophyll decomposition (Silva et al, 2007). The decrease in total chlorophyll content under DCD toxicity has been reported in lettuce plants (Padash et al, 2022). Also, the increase in carotenoid content under the side of nitri cation inhibitors can be related to the reduction of chlorophyll (Padash et al, 2022: Reeves et al, 1986.…”

“…One of the ways to reduce the harmful effects of NIs and prevent them from entering the nutrient cycle from the soil is their immobilization in the soil and plant roots with the help of plant-microorganism bioremediation technology (Padash et al, 2022). The use of microorganisms to reduce soil and plant pollution is very inexpensive and environmentally friendly, and the physical, chemical and biological characteristics of soil are preserved .…”

“…The use of microorganisms to reduce soil and plant pollution is very inexpensive and environmentally friendly, and the physical, chemical and biological characteristics of soil are preserved . The use of symbiotic fungi in reducing the negative effects of NIs was done for the rst time by Padash et al (2022). They reported that the use of Serendipita indica, G. etunicatum and G. mosseae fungi in lettuce plants reduced the concentration of DCD in the leaves of the plant, which shows the great effect of symbiotic fungi on reducing the toxicity of DCD.…”

“…The toxicity of NIs to the environment has been proven and requires a solution. In a previous experiment, we mentioned the control of DCD toxicity by symbiotic fungi in lettuce plants (Padash et al, 2022), but the toxicity of NIs is different from each other. Therefore, considering the economic relevance of lettuce and due to its high consumption as a leafy plant and the widespread use of 1, 2, 4 Triazole (TZ), this study aims to investigate the role of mycorrhizal fungi (G. etunicatum and G. mosseae) and endophyte (Serendipita indica) was done.…”