Showing 8 results for Sepehri
M. Sepehri, N. Saleh Rastin, H. Asadi Rahmani, H. Alikhani,
Volume 10, Issue 1 (spring 2006)
Abstract
Heavy metals have deleterious the effects on nodulation and N2 fixation of Rhizobium- Legume symbiosis, due to their inhibitory effects on the growth and activity of both symbionts. This research has been undertaken to evaluate the effect of Cd tolerance of native rhizobial strains on diminution of the Cd detrimental effects on Sinorhizobium meliloti-alfalfa symbiosis. For this purpose, a greenhouse experiment was conducted based on Randomized Complete Block Design. The treatments in this experiment included: plants inoculation with 6 bacterial strains (sensitive, partially tolerant and tolerant to Cd), 5 levels of Cadmium (0, 2, 5, 10, 20 mg/kg soil) and non-inoculated control. In different levels of Cd, the effects of bacterial inoculation on root nodule number and total amount of nitrogen in plant shoot were compared. The results indicated that soil pollution by Cd even at 2 mg/kg had significant effect on symbiotic properties of rhizobial strains, and according to Cd tolerance of various strains, the mentioned effect was different. Decreasing effect of Cd concentration on root nodules and nitrogen concentration in plants that were inoculated with sensitive strains in comparison with plants inoculated with tolerant strains was 68.31% and 40.8%, respectively. In this research, R95m was introduced as the best strain because of its ability for nodulation and nitrogen fixation.
R. Sepehri, Gh. Tahmasebi, M. J. Jalali Zonoz,
Volume 11, Issue 41 (fall 2007)
Abstract
During the honeybee breeding project in central Iran, sex alleles homozygoty and sex alleles number in the third generation of 364 colonies were studied in 2003. Sex alleles homozygoty was measured based on Ruttner (1988) and Tarpy and Page (2002) methods. The total area of worker brood area, stored pollen, and drone brood area were measured on the combs. The whole extracted honey weight and remaining honey in the combs were evaluated as honey production of colonies. Adult population was evaluated based on the number of full combs of adult honeybees. The results showed that sex alleles, average homozygoty and number in the colonies were 18.83% and 5.32 respectively. The results showed no significant correlation between homozygoty of sex alleles or sex alleles number and stored pollen ( P > 0.05 ) , but significant negative correlation between sex alleles homozygoty and colony population, total brood area and honey yield ( P < 0.01 ) was observed. So introduction of new sire colonies in the mating Isolated area is essential to prevent sex alleles homozygoty and also performance of honeybee colonies from decreasing.
M. Karimi Kakhaki , A. Sepehri,
Volume 13, Issue 50 (winter 2010)
Abstract
In order to study the effect of deficit irrigation at reproductive growth stages on water use efficiency and drought tolerance of four sunflower cultivars, including Azargol, Allstar, Alison and Euroflor, an experiment was conducted during 2007 growing season at experimental field of Agricultural Faculty of Bu-Ali Sina University, Hamadan, Iran. The experiment was a split plot based on randomized complete block design with three replications. The irrigation levels included full irrigation, deficit irrigation at heading, deficit irrigation at flowering, deficit irrigation at seed filling, deficit irrigation at heading and seed filling and deficit irrigation at flowering and seed filling stages. The biological and economic yield (BY and EY), harvest index (HI), water used, water use efficiency (WUE) and water stress indexes were measured. The results indicated that the highest BY (11681.7 kg.ha-1), EY (4854.0 kg.ha-1) and HI (42%) were obtained from full irrigation treatment. The lowest negative effects in cultivars belonged to deficit irrigation at seed filling stage. Euroflor obtained the highest of these parameters with 10127.1 Kg.ha-1, 4081.5 Kg.ha-1 and 40% respectively. Highest WUE was related to twice cutoff of irrigation in flowering and seed formation stages and then without irrigation in seed formation stage by 1.09 and 0.96 Kg.m-3. Allstar and then Euroflor had highest WUE among sunflower cultivars by 1.01 and 0.94 Kg.m-3 respectively. Results also indicated that Euroflor was a tolerant cultivar and STI (Stress Tolerant Index) and GMP (Geometric Mean Productivity) were acceptable indexes for selection. Finally, deficit irrigation at seed formation stage had the lowest negative effect on yield and HI with suitable WUE. In addition, Euroflor showed the highest yield, drought tolerance and HI with suitable WUE.
V. Jahandideh Mahjen Abadi, M. Sepehri, A.h. Khoshgoftarmanesh, H. R. Eshghizadeh, D. Rahmani Iranshahi,
Volume 19, Issue 71 (spring 2015)
Abstract
Zinc deficiency is the most widespread micronutrient disorder in the production of wheat (Triticum aestivum L.) and other cereal crops. An experiment was conducted in greenhouse, in 2013, using the sterile sand-perlite (2:1 v/v), to study the effects of two beneficial microorganisms on growth and nutritional status of wheat (Nicknejad cultivar). The study was arranged as factorial in a completely randomized design with three replications. The experimental factors consisted of Piriformospora indica (E0: Uninoculated E1: Inoculated), Pseudomonas putida (E0: Uninoculated E1: Inoculated) and Zinc (Zn0: 0 Zn1: 2µM ZnSO4 ). The results showed that inoculation by P. putida increased shoot dry weight at both levels of zinc, but this increase was observed for root dry weight only without zinc application. The iron concentration of shoot was decreased as a result of inoculation by P. putida at both levels of zinc. However, P. indica inoculation increased iron concentration in zinc application, but had no significant effect without zinc application. At both levels of zinc, the highest P, Zn, chlorophyll a and b concentrations were achieved by inoculation with P. indica. Inoculation by P. putida reduced P concentration at both levels of zinc but it reduced Zn, chlorophyll a and b concentrations only with zinc application. The results of this research showed that despite negative effect of P. putida on nutrient uptake, inoculation by P. putida and/or P. indica plays an important role in the promotion of wheat growth in zinc deficiency conditions.
F. Karimi, M. Sepehri, M. Afuni, M. A. Hajabbasi,
Volume 19, Issue 71 (spring 2015)
Abstract
By modifying plants at genetical, physiological and ecological levels, entophytic fungi as the most important soil microorganisms have a pronounced growth-promoting activity and also increase plant resistance to biotic and abiotic stresses. This research was undertaken to evaluate the potential of P. indica to increase barley (Hordeumvulgare L.) resistance to lead (pb). Therefore, a greenhouse experiment with two fungus treatments (non-inoculated and P. indica inoculated) and five levels of pb (0, 25, 50, 100 and 500 mg/kg) with three replications was conducted based on a factorial design. Measurement of shoot and root dry weight showed that the growth of P. indica-colonized plants at all levels of pb treatments was higher (P < 0.05) than that of the corresponding controls. Also, chlorophyll concentration of inoculated plants with P. indica was superior to non-inoculated plants. In addition, the results showed that in contrast to the plant shoot, lead concentration in the root of P. indica-colonized plants was higher than the non-inoculated controls.
Z. Sepehri, Z. Jafarian, A. Kavian, Gh. Heydari,
Volume 21, Issue 1 (Spring 2017)
Abstract
Ash and coal produced from fire influence the soil and few studies about these effects are available. For this purpose, this study was performed to investigate the effect of ash and coal on hydrological, physical and chemical properties of soil in Charat rangeland that has a history of fire. Systematic-random sampling was implemented in two plant types Astragalus gossypinus and Artemisia aucheri using 6 transects and 60 4m2 quadrates and plant and soil samples were obtained. Experimental treatments including control soil, composition soil and ash were prepared manually and also with artificial rain, composition soil and coal manually and also with artificial rain in the laboratory and characteristics of the texture, saturation moisture, pH, organic matter, field capacity, wilting point, available water and retention capacity were measured. ANOVA results for mean comparison soil, ash and coal properties showed that ash had more percent of silt and pH than soil and organic matter and lower bulk density than soil. In addition, multivariate analysis to show the effect of two types of treatments showed that manual composition of ash and coal with soil had increased field capacity and available water while composition of soil and coal with artificial rain had no significant effect on them. According to the results of this study, the presence of ash and coal resulted from burning vegetation caused great changes in soil properties, especially water retention.
F. Hosseini, M. R. Mosaddeghi, M. A. Hajabbasi, M. R. Sabzalian, M. Soleimani, M. Sepehri,
Volume 21, Issue 2 (Summer 2017)
Abstract
Soil water repellency can affect several soil properties such as aggregate stability. Soil texture and organic matter are two main internal factors responsible for the variability of soil water repellency. Major sources of organic matter in soil include plant residues, and exudates of plant roots and soil microorganisms. Tall fescue (Festuca arundinacea Schreb.) as an important cool-season perennial forage grass is usually infected by a fungal endophyte (Epichloë coenophiala) which often enhances resistance to biotic and abiotic stresses as well as altering the litter decomposition rate and soil properties. In this study, the effects of endophyte-infected (E+) and endophyte-free (E−) tall fescue residues (in three different levels of 0, 1 and 2%) on soil organic carbon, basal microbial respiration, water-dispersible clay and water repellency index (determined by intrinsic sorptivity method) were investigated in four texturally-different soils in the laboratory. E+ and E− tall fescue residues were completely mixed with moist soil samples and then were incubated at 25 °C. During two months of incubation period, the amended soil samples were subjected to 10 wetting and drying cycles and then, the above-mentioned soil properties were measured. The results indicated that soil organic carbon and water-dispersible clay were greater, while basal soil respiration and repellency index were lower in fine-textured soils. Water repellency index was increased by production of hydrophobic substances (for the rate of 1%) and was reduced by induced greater soil porosity (for the rate of 2%). Presence of endophyte in plant residues had no significant effect on water sorptivity, ethanol sorptivity and water repellency index; nevertheless, E+ residues increased soil organic carbon and decreased water-dispersible clay significantly. Overall, it is concluded that tall fescue residues, especially those with E+, can improve soil physical quality due to improving soil organic carbon storage and water repellency index and decreasing water-dispersible clay (as an index for aggregate instability). These E+ species and the residues have great potential to be used in sustainable soil conservational managements.
M. J. Asadollahzade, A. H. Khoshgoftarmanesh, M. Sepehri,
Volume 21, Issue 4 (Winter 2018)
Abstract
Iron (Fe) and zinc (Zn) deficiency is common in wheat growing areas of the world particularly in calcareous soils. Soil application of chemical fertilizers is considered as a cost-effective and easy approach to combat micronutrient deficiency. However, due to economic, environmental, and agronomic constrains, efficiency of soil fertilization is low in most calcareous soils. Therefore, finding proper and effective approaches to improve fertilizer use efficiency and/or soil availability of metal nutrients is of great importance. This research was performed to investigate the effect of endophyte fungus Piriformospora indica and Zn-sulfate application on root and shoot dry matter yield and uptake of Fe and Zn by wheat. The experiment was set up in a completely randomized factorial design; each treatment contained three replicates. Two wheat cultivars (Triticum aestivum L. cvs. Durum and Rushan) were exposed to two Zn fertilizer rates (0 and 15 mg/kg ZnSO4.7H2O) and were inoculated with and without P. indica. Results showed that inoculation with P. indica increased root and shoot uptake of Fe (25 and 27%, respectively) and Zn (46 and 26%, respectively). In general, inoculation of roots with P. indica resulted in significant increase of shoot and root dry matter yield and uptake of Fe and Zn by both studied wheat cultivars. Infection of wheat roots with P. indica seems to be an effective and environment-friendly approach to improve Fe and Zn uptake in calcareous soil; although further research is needed to clarify all aspects of this approach
