جستجوی مقالات مرتبط با کلیدواژه « گلوموس اینترارادیسز » در نشریات گروه « آب و خاک »

The accumulation of heavy metals in water, sediments, and soils has led to serious environmental problems. In recent years, several processes have been developed with the aim of reducing or recovering heavy metals from contaminated environments. Physical and chemical approaches are capable of removing a broad spectrum of contaminants, but the main disadvantages of these methods lie in the increased energy consumption and the need for additional chemicals. In recent years, the processes such as bioleaching, biosorption, bioremediation, phytoremediation, and bio precipitation are all based on the use of microorganisms that have the ability to solubilize, adsorb, or precipitate heavy metals. Therefore, it is necessary to find some solutions to reduce the negative effects of heavy metals in soil. A factorial experiment was conducted in the greenhouse of the Faculty of Agriculture, the University of Zanjan, using a completely randomized design with three replications. In this experiment, the effects of different levels of soil cadmium (0, 5, 10, 25, and 50 mg/Kg) and soil inoculation (without inoculation and inoculation with Glomus mosseae, Glomus intraradices, Glomus mosseae + Rhizobium trifolii, Glomus intraradices + Rhizobium trifolii bacterium, Rhizobium trifolii, Glomus mosseae + Glomus intraradices and Glomus mosseae + Glomus intraradices + Rhizobium trifolii) on growth of berseem clover were assessed. The results of this study showed that the soil cadmium levels has a significant effect (p < 0.05 and p < 0.01) on fresh weights of aerial parts and roots, height, number of the plant in the pot, Fe, Zn and Cd concentrations in aerial parts and roots of berseem clover. The fresh weights of aerial parts and roots, height, number of the plant in the pot, Fe and Zn concentrations in aerial parts and roots of berseem clover decreased as the levels of soil cadmium increased. The lowest concentrations of iron and zinc were measured in treatment with 100 mg Cd/Kg. Also, Cd concentration in aerial parts and roots increased as the level of soil cadmium increased. The results of this experiment showed that soil inoculation with mycorrhizal fungi and Rihzobium trifolii had a significant effect (p < 0.05 and p < 0.01) on fresh weights of aerial parts and roots, height, number of plant per pot, Fe, Zn and Cd concentrations in aerial parts and roots of berseem clover. The inoculation of soil with mycorrhizal fungi and Rhizobium trifolii increased the fresh weights of aerial parts and roots, height and No. of plant per pot. The highest fresh weights of aerial parts and roots of berseem clover, height, and number of plant per pot were obtained in treatments co-inoculated with Glomus mosseae and Rhizobium trifolii. The highest and lowest concentrations of iron and zinc in aerial parts and roots of berseem clover were measured, respectively, for the treatment co-inoculated by Glomus mosseae and Rhizobium trifolii and control treatment (without inoculation). However, the opposite trends were found in Cd concentrations in the plant. The highest and lowest Cd concentrations in aerial parts and roots were measured in control treatment (without inoculation) and treatment co-inoculated by Glomus mosseae and Rhizobium trifolii (MT), respectively. Bioremediation and phytoremediation are considered as two very safe and necessary technologies which naturally occur in the soil by microbes and plants and pose no hazard to the environment and the people life. The procedure of bioremediation and phytoremediation can be simply carried out on site without initiating a major disruption of normal actions and threating the human life and the environment during transportation. Bioremediation and phytoremediation are used less than other technologies for cleaning-up the wastes and contaminated soils. Microorganisms and plants possess inherent biological mechanisms that enable them to survive under heavy metal stress and remove the metals from the environment. These microbes use various processes such as precipitation, biosorption, enzymatic transformation of metals, complexation and phytoremediation techniques of which phytoextraction and phytostabilization have been very effective. However, environmental conditions need to be adequate for effective bioremediation. The use of hyperaccumulator plants to remediate contaminated sites depends on the quantity of metal at that site and the type of soil. The results of this experiment showed that the Rhizobium trifolii and Glomus mosseae could be used to reduce the soil cadmium contamination. Also, the berseem clover is a hyperaccumulator plant for phytoremediation of cadmium in soils. According to the results of this study, co-inoculation of mycorrhizal fungus Glomus mosseae and Rhizobium trifolii can be recommended to improve the yield and uptake of micronutrients such as iron and zinc in cadmium contaminated soils.

An experiment was conducted to evaluate the effect of arbuscular mycorrhizal fungi (AMF) and vermicompost on biological yield، stem height، spike length، and concentration and uptake of zinc (Zn)، iron (Fe)، manganese (Mn) and copper (Cu) in straw of two wheat cultivars as a factorial experiment arranged in a completely randomized design (CRD) with three replications under greenhouse conditions. Treatments included two levels of AMF (with and without AMF)، two levels of vermicompost (0 and 1%، w/w)، and two wheat cultivars (Shiraz and Bahar). Results showed that maximum biological yield، stem height and spike length obtained by application of vermicompost (without AMF) in Bahar cultivar. Biological yield، spike length، Zn and Mn concentrations، and total uptake of Zn، Fe، Mn and Cu significantly affected by vermicompost application. Maximum concentration and uptake of Zn observed in AMF treatments (without vermicompost) in Bahar cultivar. Mn uptake was increased when vermicompost and AMF were applied to soil samples but it was decreased when AMF was not applied. Biological yield، stem height، concentration and uptake of Zn and Mn were higher in Bahar cultivar compared to Shiraz cultivar. It might be concluded that biological fertilizers increased the wheat yield which is a strategic product. Yield and micronutrients uptake in Bahar cultivar were higher than Shiraz ones.

Colonization of roots with arbuscular mycorrhizal fungi (AMF) often improves micronutrients uptake by most of the plants. Measurement of pH in mycorrhizae leachates is an evidence for acidification or alkalinization of rhizosphere and hyphosphere. Leachate pH is very important factor for assessment of micronutrient uptake by AMF. This experiment was laid out in factorial complete randomized block design with three replications. The first factor consists of arbuscular mycorrhizal fungi with Glomus etunicatum and Glomus intraradices species and control, the second factor was Rorison’s nutrient solution with zero, half and full strength of micronutrients, and the third factor was time of measurement of leachates pH that was include 45, 65 and 85 days after sowing. Tomato (Lycopersicon esculentum Miller) and sorghum (Sorghum bicolor L.) plants were grown in sterile perlite and were inoculated with either Glomus etunicatum or G. intraradices, while the control set was left un-inoculated. Rorison's nutrient solution with three levels of 0, half and full strength of micronutrients was applied to the pots during vegetative growth period. The pH of leachates Measured at 45, 65 and 85 days after sowing (DAS). Results show that, colonization of sorghum roots by G. etunicatum and G. intraradices fungi were 43 and 37%, respectively. On the contrary of sorghum plants, the mycorrhizal symbiosis was not observed in tomato plants. The pH of leachates was lower in mycorrhizal than non-mycorrhizal plants. G. intraradices were efficient than G. etunicatum in this respect. The reduction in leachate pH was induced at 0 levels of the micronutrients. 65 DAS, leachates had minimum amount of pH. In all of treatments, pH of leachates were higher than 7.6. It seems that, the main agent of this phenomenon is nitrate nutrition of plants, because nitrate is the most source of N in Rorison’s nutrient solution.

Improper application of phosphorus chemical fertilizers does not increase crop yield. Indeed, it may cause various problems in absorption of microelements by plants, specially in calcareous soils. The present study was conducted to evaluate use of azotobacter and mycorrhiza as bio-fertilizer and phosphorus (super phosphate) as chemical fertilizer on corn crop (var. KSC 704). The effects of three factors including Azotobacter chroococcum (inoculated and not inoculated), Glomus intraradices (inoculated and not inoculated) and phosphorus (0, 50, 100, and 200 kg/ha) was evaluated in a factorial experiment using completely randomized block design with three replications. The effects of the three factors and their interactions were investigated on some parameters such as root colonization, dry matter, Zn, Fe, Cu, Mn and P concentration in shoot tissues. The results showed that mycorrhizal symbiosis increased dry matter (4.9 %), with accompanying significant decrease in Cu (14.9 %) and Mn (9 %) and increase in P (28.8 %) in shoot tissues concentration. Application of azotobacter improved the metabolites that were effective in increasing growth of plant tissues and dry matter (7.5 %), but led to significant decrease in Fe concentration (about 6.7 %). Different levels of phosphorous significantly increased P (25.6 %) in shoot tissues while decreasing concentration of Cu (22.2 %), Fe (21.4 %), Zn (15.8 %), and root colonization (about 16.6 %). The interaction between mycorrhiza and azotobacter also increased root colonization (43.3 %), dry matter (12 %) and P concentration (48.8 %), but decreased Fe (11.8 %) and Cu (15.6 %) concentration significantly (P<0.05 %) with no effect on Zn and Mn. The triple interaction of mycorrhiza, azotobacter, and phosphorus was not evident.