Arbuscular Mycorrhizal Fungi Promote Gleditsia sinensis Lam. Root Growth under Salt Stress by Regulating Nutrient Uptake and Physiology

Abstract

Towards the improvement of plant productivity in saline–alkali soils, the application of arbuscular mycorrhizal fungi (AMF) is an intensive topic of research. For this study, three inoculation treatments, namely, autoclaved AMF inocula (CK), Funneliformis mosseae (FM), and Corymbiglomus tortuosum (CT), and four NaCl levels, namely, 0, 50, 100, and 150 mM were established to investigate the growth and physiological responses of mycorrhizal Gleditsia sinensis Lam. root systems to increase salinity through root dry weight, morphology, nutrient content, and physiology, and soil nutrient content. As NaCl levels increased, root dry weight, morphology, and nutrient content under the CK treatment exhibited a downward trend, while FM and CT treatments weakened this trend and significantly improved root dry weight and morphology, which increased by more than 200%. Under high NaCl levels, root activity under the FM treatment was significantly higher than that under the CK, with an average increase of 120.86%. In contrast to the activity of nitrate reductase, niacinamide adenine dinucleotide oxidase activity under CK was significantly less than that in FM and CT treatments. Moreover, inoculation with AMF significantly affected soil alkali-hydrolyzable nitrogen (AN), total nitrogen (TN), and phosphorus (TP), while NaCl had no significant impact on soil nutrients. Further, both soil salinity and mycorrhizal colonization rate had significant direct effects on root growth. However, soil salinity primarily influenced root growth through indirect effects on root nitrogen content, while mycorrhizal colonization rate indirectly impacted root nitrate reductase activity, and root nitrogen and phosphorus content. Our results suggested that the use of suitable AMF (e.g., Funneliformis mosseae) might effectively improve the currently unfavorable situation of economic tree species production on land with saline soils, which may greatly optimize the utility of these areas.

Arbuscular mycorrhizal fungi affect the expression of PxNHX gene family, improve photosynthesis and promote Populus simonii×P. nigra growth under saline-alkali stress

“…Under saline-alkali stress, the activities of plants and microorganisms could be inhibited ( Arab et al., 2018 ; Ma et al., 2022a ). Previous studies have shown that the saline-alkali tolerance of plants was positively correlated with biomass ( Chen et al., 2017 ).…”

Effect of Arbuscular Mycorrhizal Fungi (AMF) on photosynthetic characteristics of cotton seedlings under saline-alkali stress

“…AMF's invasion of cotton roots alleviates salt toxicity, thereby enhancing root nutrient absorption from the surrounding medium. This, in turn, boosts essential element levels for chlorophyll synthesis in aboveground plant parts, facilitating chlorophyll synthesis and metabolism in leaves 17 . Additionally, AMF plays a role in reducing PSII (Photosystem II) sensitivity to photoinhibition by optimizing photon utilization and photosynthetic electron transport.…”

Mycorrhizas Affect Physiological Performance, Antioxidant System, Photosynthesis, Endogenous Hormones, and Water Content in Cotton under Salt Stress

“…Under salt stress, the infection activity of AMF and plant physiology were inhibited [ 45 ]. In this study, P. occultum was successfully colonized with cotton.…”