Arbuscular mycorrhizal fungi (AMF), rhizobia and phosphate-solubilizing bacteria play an active role in plants and soils effect.
This post mainly studies the cooperative symbiotic relationship and interaction among AMF, rhizobia and phosphate-solubilizing bacteria, and summarizes the effects of inoculation with AMF, phosphate-solubilizing bacteria and rhizobia on plant growth, soil remediation and microbial growth.
Arbuscular mycorrhizal fungi (AMF) are ubiquitous on earth and can form a symbiotic relationship with more than 80% of plants on land, and can also enhance the ability of plants to resist biotic and abiotic stresses.
AMF can also form cooperative symbiotic relationships with other microorganisms, and their interactions have positive effects on plant growth.
AMF belongs to a class of soil fungi belonging to the glomeromycota. The hyphae of AMF can attach to the roots of plants, and gradually penetrate into the root cortex as the hyphae grow, and finally form a special structure: intracellular and intercellular hyphae.
AMF belongs to a class of soil fungi belonging to the phylum Glomus. The hyphae of AMF can attach to the roots of plants, and gradually penetrate into the root cortex as the hyphae grow, and finally form a special structure: intracellular and intercellular hyphae.
The mycelium spreads outward with the plant root as the center, so that the contact area between the mycelium and the soil gradually increases, and through the absorption of the mycelium, it provides water and nutrients for the growth of the plant. The plant secretes through the root system, which also provides nutrients for the growth of AMF.
AMF & Rhizobium
There is a symbiotic relationship between AMF and legume rhizobia, which is an important member of ecological symbiosis.
We found that inoculation with AMF could enhance some abilities of rhizobia, such as nitrogen fixation. In addition, the combined action of AMF and rhizobia can also greatly enhance the growth of legumes. Compared with the single inoculation, the double action of AMF and rhizobia could significantly improve the yield of cowpea, indicating that the advantage of the combined effect was much greater than that of the single inoculation.
In the experiment, we found that the number of nodules of mycorrhizal plants was much higher than that of non-mycorrhizal plants, indicating that AMF could enhance the nodulation and nitrogen fixation ability of rhizobia. AMF was also able to enhance the infectivity of rhizobia and increase the number of rhizobia in the roots of legumes. And AMF can also provide nutrients such as phosphorus and potassium for legumes and rhizobia.
AMF & Phosphate Solubilizing Bacteria
Phosphorus is an important nutrient element required for plant growth, and its content is high in soil, but the content of available phosphorus is less, and most of it exists in the form of insoluble phosphate compounds.
Phosphate solubilizing bacteria usually dissolve insoluble phosphate compounds in soil by releasing phosphatases and organic acids, increasing the concentration of phosphorus that plants can absorb in the soil, maintaining the demand for phosphorus in plants, and maintaining normal ATP energy supply in plant growth and development.
There is a symbiotic relationship between AMF and phosphate-solubilizing bacteria, and studies have shown that double inoculation of AMF and phosphate-solubilizing bacteria significantly enhanced plant growth compared with single inoculation.
The fructose secreted by AMF can stimulate the expression of the phosphatase gene of phosphate-solubilizing bacteria, promote the secretion of phosphatase, and greatly increase the activity of phosphatase.
AMF & PSM & Rhizobium
When the content of available nitrogen and available phosphorus in the soil is deficient, the ability of inoculating rhizobia alone is not good for nitrogen fixation. When AMF and rhizobia were inoculated at the same time, the nitrogen fixation capacity of nodules was significantly enhanced compared with no AMF inoculation.
When the content of available nitrogen and available phosphorus in the soil is deficient, the ability of inoculating rhizobia alone is not good for nitrogen fixation. When AMF and rhizobia were inoculated at the same time, the nitrogen fixation capacity of nodules was significantly enhanced compared with no AMF inoculation.
When rhizobia were inoculated into nitrogen and phosphorus-deficient soils and a sufficient amount of available phosphorus was applied, the nitrogen-fixing ability of rhizobia was also enhanced.
It shows that phosphorus plays an important role in nitrogen fixation by rhizobia. When the soil deficient in nitrogen and phosphorus was inoculated with phosphate-solubilizing bacteria and rhizobia at the same time, the phosphate-solubilizing bacteria could decompose the insoluble phosphate compounds in the soil into available phosphorus, and the content of available phosphorus in the soil increased, resulting in enhanced nitrogen fixation ability of rhizobia.
The combined inoculation of AMF, rhizobia and phosphorus-solubilizing bacteria can not only enhance plant growth, but also increase the nitrogen and phosphorus content in the soil and enhance the soil water holding capacity, indicating that there is a positive symbiotic relationship among the three.