Role of Arbuscular Mycorrhiza in Alleviating Salinity Stress in Wheat (Triticum aestivum L.) Grown Under Ambient and Elevated CO₂

Abstract

Plant growth and development are influenced by future elevated atmospheric CO 2 concentration and increased salinity stress. AM (arbuscular mycorrhiza) symbiosis has been shown to improve plant growth and resistance to environmental stresses. The aim of this study was to investigate the potential role of AM fungus in alleviating salinity stress in wheat (Triticum aestivum L.) plants grown under ambient and elevated CO 2 concentrations. Wheat plants inoculated or not inoculated with AM fungus were grown in two glasshouses with different CO 2 concentrations (400 and 700 lmol l À1 ) and salinity levels (0, 9.5 and 19.0 dS m À1 ). Results showed that salinity stress decreased and elevated CO 2 increased AM colonization. AM inoculation increased plant dry weight under elevated CO 2 and salinity stress. Stomatal conductance, density, size and aperture of AM plants were greater than non-AM plants. AM fungi enhanced NUE by altering plant C assimilation and N uptake. AM plants had higher soluble sugar concentration and [K + ]: [Na + ] ratio compared with non-AM plants. It is concluded that AM symbiosis improves wheat plant growth at vegetative stages through increasing stomatal conductance, enhancing NUE, accumulating soluble sugar, and improving ion homeostasis in wheat plants grown at elevated CO 2 and salinity stress.

Arbuscular mycorrhiza enhances nutrient accumulation in wheat exposed to elevated CO2 and soil salinity

“…However, shoot N concentration was lower in the AM plants than that in the non‐AM plants under elevated CO 2 and salt stress (Tab. ), which is consistent with the results of Zhu et al (). An extra increase in C accumulation and growth of the AM plants was observed in relation to N uptake, indicating an N dilution effect ( Zhu et al, ).…”

“…Our previous study showed that salt stress inhibited AM colonization, while elevated CO 2 concentration enhanced AM colonization ( Zhu et al, ). Plants under elevated CO 2 might allocate more C to AM fungi and benefit the AM colonization ( Compant et al, ).…”

“…), consistent with the results in alfalfa that greater contents of soluble sugar, sucrose, and glucose were found in the AM than in the non‐AM plants under elevated CO 2 ( Baslam et al, ). The enhanced sugar concentration in the AM plants might be due to the increased photosynthetic capacity and higher organic acid contents ( Yu et al, ; Zhu et al, ). The requirement for C by the AM fungi could cause an increased accumulation of sugars.…”

“…For instance, increased Na + concentration of salt-stressed plants decreases K + concentration and results in nutritional imbalance (Zuccarini and Okurowska, 2008;Yan et al, 2013). Elevated CO 2 concentration is able to alleviate the adverse effect of salt stress on plants (Pé rez-Ló pez et al, 2012;Zhu et al, 2016c). However, the elevated CO 2 concentration reduces the mineral concen-tration in wheat (Li et al, 2016).…”

Interactive Impact of Arbuscular Mycorrhizal Fungi and Elevated CO2 on Growth and Functional Food Value of Thymus vulgare

“…It is known that AMF are largely dependent on their host plant for carbon, so they are sensitive to climatic changes that affect their host plant [ 14 ]. In this sense, eCO 2 could have an indirect effect on mycorrhizal colonization by promoting carbon assimilation and allocation to roots [ 29 ]. Since AMF are attached to plant roots, they are lucky to receive higher amount of photosynthates under eCO 2 before other soil microbes [ 30 ].…”