قارچ میکوریز

This study was carried out to isolate and identify plant growth-promoting rhizobacteria (PGPR) from saline soils and to evaluate the effect of isolated rhizobacteria, as well as symbiotic and endophytic fungi on the concentration of some nutrient elements in wheat plants under salinity stress in greenhouse conditions. Factors included microbial treatments (rhizobacteria, mycorrhizal fungi, endophytic fungus, and control) and salinity levels (no salinity, 8 and 14 dS m-1). At the end of the growth period, the concentrations of nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), iron (Fe), zinc (Zn) and manganese (Mn) in the shoot of the wheat plant, as well as the percentage of root colonization were measured. Based on growth-promoting trails, three isolates among the ten purified rhizobacteria were selected for phenotypic and molecular identification. Two identified isolates belonged to Pseudomonas genus (Pseudomonas aeruginosa Ur743 and Pseudomonas fluorescens Ur745), and the last one was Stenotrophomonas maltophilia Ur840. When the concentrations of nutrient elements were at the non-salinity level, mycorrhizal fungi were better than other microbial treatments in terms of absorbing P, Fe, and Mn, However, at the highest salinity level (i.e., 14 dS m-1), rhizobacteria significantly improved concentrations of N, P, Fe, and Mn in the plant shoot, compared to the control. Besides, the PGP bacteria increased the concentrations of K and Zn, as well as K:Na ratio by 1.99, 1.71, and 1.37 times, respectively, as compared to the control. In general, native microorganisms isolated from saline soil, as compared to other microorganisms in this study, improved the nutrient uptake and increased the wheat plant biomass under salinity stress.

To investigate the effect of integrative application of mycorrhizal fungus and chemical fertilizer on the quantitative and qualitative characteristics of medicinal plant dragon’s head (Lallemantia iberica Benth.) under rainfed conditions, an experiment was conducted as a randomized complete block design with seven treatments and three replications in the research farm of Maragheh University, Iran, in 2017. Treatments included 100% conventional chemical fertilizer (250 and 150 kg ha-1 urea and triple superphosphate, respectively), Glomus mosseae (GM), G. intraradices (GI), 50% chemical fertilizer+GM, 50% chemical fertilizer+GIand 50% chemical fertilizer+GI+GM. The results demonstrated that the highest (802.8 kg ha-1) and lowest (463.5 kg ha-1) seed yield and the highest (40.64%) and lowest (25.85%) harvest index were achieved in the integrative application of 50% chemical fertilizer+GI+GMand separate application of GI treatments, respectively. Besides, the highest content (9.18%) and yield (73.75 kg ha-1) of mucilage was observed in 50% chemical fertilizer+GI+GM treatment. Furthermore, the highest amount of mucilage compounds (glucuronic acid, galacturonic acid, arabinose, raffinose, galactose, glucose, xylose and rhamnose) was obtained in 50% chemical fertilizer+GI+GM treatment. Based on cluster analysis, the treatments were divided into three groups. In general, the application of 50% chemical fertilizer+GI+GM while reducing the use of chemical fertilizers improved the quantitative and qualitative yield of the dragon’s head.

Chickpea (Cicer arientinum L.) is one of the Leguminosae family members that has symbiotic ability with Mesorhizobium ciceri bacteria and arbuscular mycorrhizal (AM) fungi. To evaluate the effect of AM fungi (Glomus mosseae, Glomus intraradices) and Mesorhizobium ciceri bacteria at three soil moisture levels [28% (field capacity), 15% (-5 bar suction) and 9% (-10 bar suction)] on nutrients concentration of roots, areal parts of chickpea and post-harvest soil, a greenhouse factorial experiment was conducted, arranged as a completely randomized design, in sterilized soil. Results showed that moisture content had significant effect on potassium (K) concentration of roots, areal parts and post-harvest soil; the highest positive effect of moisture was at field capacity level. Rhizobium bacteria had significant effect on concentration of K and nitrogen (N) of the roots, phosphorus (P) of the areal parts, and post-harvest iron (Fe) concentration in the soil. AM fungi had significant effect on root P concentration of the roots; the highest effect was related to Glomus mosseae. Interaction of moisture and AM fungi was significant on concentration of root P and areal parts manganese (Mn); the highest effect was related to Glomus mosseae treatment at field capacity moisture level. Interaction of moisture and rhizobium bacteria was significant on concentration of root N and P, and areal parts Mn and Fe; the highest effect was related to rhizobium treatment at field capacity moistute level. Interaction of AM fungi and rhizobium bacteria was significant on root P concentration; the highest effect was related to rhizobium and Glomus mosseae treatment. The highest root N concentration was related to combination of AM fungi and inoculation with rhizobium treatment at field capacity moisture level.