عنوان مقاله [English]
Introduction; Rising global demand for food, along with the limitation of arable land, has posed a major challenge for agricultural researchers. Given that the development of agricultural lands is not practically possible, most attention should be focused on increasing the production yield per unit area. One of the basic approaches to increase crop yield is the consumption of more types of inputs, especially chemical fertilizers, despite their application poses problems for humans, soil and the environment. In addition to decreasing the use of chemical fertilizers, organic fertilizers can be considered as a suitable solution to solve this problem. Organic compounds and biomass are the main factors of soil fertility, maintain soil fertility as well as its productivity. One way to increase soil organic substance is the applying organic fertilizers such as living compounds (bacteria, yeast, Azolla) and non-living compounds (compost tea, amino acids, humic acid and fulvic acid). Arbuscular Mycorrhizal Fungi are cosidered as beneficial microorganisms. Arbuscular mycorrhizal fungi promote plant growth by establishing a symbiotic relationship with plants. The colonization of plant roots by these fungi increases plant resistance to biotic and abiotic stresses, enhances growth through increasing elements uptake, improves the water flow of plants, and protects plants against diseases. Due to the importance of some food products such as Zea mays, investigation of various aspects of the mycorrhizal fungi application and their effect on these products is important.
Materials and Methods; In this study, in order to investigate the efficacy of some organic compounds and microorganisms on the colonization of arbuscular mycorrhizal fungi and uptake of some elements trough the plant roots, a factorial experiment in greenhouse conditions was conducted in a completely randomized design with three replications for 3 months. This study involved the fungal factor at three levels, Funneliformis mosseae (FM), Rhizophagus intraradices (RI), and Rhizophagus irregalaris (RIr), and the organic enhancer factor at seven levels (Azolla, P. fluorescens VUPf5 bacterial strain, Amino acid complex, Humic acid, Yeast, Bacterial siderophore and Compost tea).
Results and Discussion; The results of this study showed that the highest root mycorrhizal colonization percentage by Funneliformis mosseae (FM) was observed in bacterial (93%), humic acid (90%) and Azola (76%) treatments, respectively. Treatments of Azola and humic acid with 96% and compost tea with 82% showed the highest effect on R. intraradices (Ir) colonization. Also, Azola (96%) and compost tea (90%) had the greatest effect on the root colonization percentage by R. irregalaris (Rir). According to the results, the main increase in root colonization percentage by three mycorrhizal species was observed in Azola, humic acid, compost tea and bacterial treatments. The results showed that some compounds increased the concentration of nutrients in the roots and shoots of the treated plant. The function of these compounds is as a stimulant in mycorrhizal fungi and it seems mainly via root stimulation and rooting and creating signals related to the roots of the plant and mycorrhizal fungi. According to the results, all mycorrhizal species significantly increased the amount of phosphorus (69.5%) in the shoot under the compost tea application. Treatment of amino acid along with R. irregaluris caused to increase in the concentration of iron, compared to the control. Application of R. intraradices along with amino acid increased manganese concentration by 2.87 times compared to the control. Simultaneous application of siderophore and RI, FM and Rir increased the concentration of zinc 2.16, 2.55 and 1.81 times compared to the control, respectively. Results of the present study indicated an increase in the uptake of elements by all three species of mycorrhizal fungi and the performance of these fungi accompanied with compost tea, amino acid complex and siderophore had a better outcomes compared to the control. The highest uptake of phosphorus, zinc and manganese was observed using R. intraradices and iron in inoculated plant with R. irregaluris. The mean comparison of different treatments effect revealed no significant differences between non- mycorrhiza and mycorrhiza-treated samples, while in comparison with the control, their differences were significant. Overall, concomitant use of mycorrhizal fungi with azolla, bacterial and humic acid has the greatest increase in the mycorrhizal root colonization and treatments of compost tea, amino acid complex and siderophore has the highest impact on nutrient content increase in plant.
Keywords: Arbuscular mycorrhizal fungi, Elements content, Root colonization, Synergistic effect