Arbuscular mycorrhizal fungi (AMF) enhance the tolerance of Euonymus maackii Rupr. at a moderate level of salinity

Abstract

Salt stress is one of the major environmental constraints for plant growth. Although the ways in which mycorrhizal plants deal with salt stress have been well documented, it still is blank for Euonymus maackii, an important local ecological restoration tree, to arbuscular mycorrhizal fungi (AMF) inoculation and salt stress. In this study, we tested the effect of different salt levels (0, 50, 100,150 and 200 mM) and AMF inoculation on E. maackii growth rate, photosynthesis, antioxidant enzymes, nutrient absorption and salt ion distribution. The results indicated negative effect of salt on height, photosynthesis capacity, nutrition accumulation, while salt stimulated the antioxidant defense system and salt ions accumulation. The toxic symptom by excessive accumulation of salt ions worsen with salt level increased gradually (except for the 50 mM NaCl treatment). AMF inoculation alleviated the toxic symptom under moderate salt levels (100 and 150 mM) by increasing photosynthesis capacity, accelerating nutrient absorption and activating antioxidant enzyme activities under salt stress. Meanwhile, effect of AMF was not detected on seedlings under slight (0 and 50 mM) and high (200 mM) NaCl concentration. Our study indicated AMF had positive impact on E. maackii subjected to salt, which suggested potential application of AMF-E. maackii on restoration of salt ecosystems.

Roles of Arbuscular Mycorrhizal Fungi on Plant Growth and Performance: Importance in Biotic and Abiotic Stressed Regulation

“…This is mainly related to a combination of biochemical, physiological, and nutritional effects [97,[109][110][111][112][113][114][115][116]. Among the mechanisms involved in salinity tolerance in AMF inoculated plants, we have the enhancement of water absorption capacity and nutrient uptake, the accumulation of osmoregulators like proline and sugars [105], the ionic homeostasis [87,117], and the reduction in Na + and Cl − uptake [118]. In addition, it has been demonstrated that AMF colonization improves stomatal conductance and reduces the oxidative damage in plants exposed to salinity [112,119,120].…”

Plant Growth Promoting Rhizobacteria, Arbuscular Mycorrhizal Fungi and Their Synergistic Interactions to Counteract the Negative Effects of Saline Soil on Agriculture: Key Macromolecules and Mechanisms

“…The AMF produce auxins and cytokinins (CKs) that help in the growth and development of the plant and also stimulate the synthesis of these hormones in plants under stress [ 148 ]. Plants associated with AMF show enhanced synthesis of abscisic acid (ABA), jasmonic acid (JA), and salicylic acid (SA) that act as signal molecules during the process of AMF symbiosis [ 113 , 116 , 149 ]. Modulation of phytohormone synthesis by AMF confers drought and salt tolerance in plants [ 150 ].…”

“…4.1.6. Antioxidant Production AMF facilitate plants to modulate salinity stress by increasing the activities of antioxidant enzymes such as catalase (CAT), superoxide dismutase (SOD), peroxidase (POD), ascorbate peroxidase (APX), glutathione reductase (GR), monodehydroascorbate reductase (MDHAR), and dehydroascorbate reductase (DHAR), and glutathione-S-transferase that protect plants from oxidative damage [112,146,149,155]. These enzymes help to alleviate the excess ROS and maintain the equilibrium of the formation and removal of ROS, providing the host plant better tolerance against oxidative stress.…”

Mycorrhizal Symbiosis for Better Adaptation of Trees to Abiotic Stress Caused by Climate Change in Temperate and Boreal Forests

“…Overall, mycorrhizal fungi have the potential to conserve and restore temperate and boreal forest ecosystems and to maintain sustainable forestry crops under stress due to global changes (Bothe et al, 2010;Field et al, 2020;Li et al, 2020). Numerous studies have shown improved tolerance of mycorrhizal trees to numerous abiotic stresses, such as high temperatures, drought, high salinity, and flooding (Figure 1).…”