Co-inoculations of arbuscular mycorrhizal fungi and rhizobia under salinity in alfalfa

Abstract

Alfalfa (Medicago sativa L.) is cultivated in arid and semi-arid regions where salinity is one of the main limiting factors for its production. Thus, this experiment was conducted to evaluate the efficacy of arbuscular mycorrhizal fungus (AMF), Glomus mosseae, alfalfa rhizobia Sinorhizobium meliloti (R) seed inoculation in the development of salinity tolerance of different alfalfa cultivars (Rehnani, Pioneer and Bami) under a variety of salinity levels. The results revealed that under non-stress condition, root mycorrhizal infection, nodulation (the number and weight of nodules per plant), potassium (K), calcium (Ca), phosphorus (P), zinc (Zn), copper (Cu) and magnesium (Mg) contents of the root and shoot, the value of the K/ Na ratio, protein [calculated from the nitrogen (N) content] and proline contents of the shoot and the alfalfa yield were found to be the highest while Na contents of the root and shoot were seen to be the lowest when seeds were double inoculated followed by mycorrhizae, rhizobium and control treatments, respectively. Similarly, under salinity condition, the greatest amounts of mycorrhizal infection, nodulation, root and shoot P contents, the value of K/Na ratio, the shoot proline content and the root Ca content were enhanced with the least amount of leaf Na content related to the cases of seeds which were double inoculated, followed by mycorrhizae, rhizobium and control treatments respectively. The results suggested that inoculation of alfalfa seed with AMF or R, especially double inoculation, causes a considerable increase in alfalfa yield under both saline and non-saline conditions by increasing colonization, nodulation and nutrient uptake.

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

“…Generally, an increase in crop yield of approximately 30–40% was observed in combined PGPR and AMF inoculation in field studies. Co-inoculation of Rhizobium with AMF resulted in significant enhancement of yield, nodulation, leghemoglobin, nitrogenase activity, IAA synthesis, and nutrient uptake of alfalfa subjected to salinity stress [ 166 ]. Inoculation of soybean with AMF improved various attributes as observed in alfalfa, but also conferred protection against membrane damage by reducing hydrogen peroxide and lipid peroxidation [ 167 ].…”

Arbuscular Mycorrhizal Fungus Improves Rhizobium–Glycyrrhiza Seedling Symbiosis under Drought Stress

“…The possibility of extending the beneficial effects of plant-rhizobia symbiosis by introducing AM fungus into the symbiont under stress conditions is becoming a popular research topic [40,41]. Our results showed AM fungus enhanced the nodulation and significantly improved plant growth compared to single rhizobial inoculation.…”

Effects of arbuscular mycorrhizal fungi, rhizobium and phosphorus on mungbean (Vigna radiata) in saline soil

“…Under salinity condition, the greatest amount of mycorrhizal infection, nodulation, P concentration and the root Ca concentration of alfalfa plants were recorded when plants were double inoculated. (Ashrafi et al, 2014).…”