Showing 98 results for روی
M Ebrahimi, S.m Khayam Nekoei, S Kadkhodaei,
Volume 12, Issue 46 (1-2009)
Abstract
Somatic embryogenesis is affected by several factors. In this research project, we studied the effect of explant size, wounding and desiccation treatments on somatic embryogenesis and their conversion into plantlet among three genotypes of soybean. The explants were sampled from immature embryos of soybean in three different sizes (3, 5 & 7 mm) with wounding treatment on half of each, and then were cultured on the somatic embryogenesis medium. In order to determine desiccation effect on conversion amount of embryos into plantlets, the produced embryos were affected by three levels of desiccation treatments (2, 4 & 6 days). The increase ratio of callus mean weight, percentage of embryogenic calli, embryo number per explant and percentage of embryo conversion to plantlet were used for treatment evaluation. Variance analysis of the data showed significant differences (P<0.01) between treatments regarding the variables. The results indicated that BP was a superior genotype with embryogenic capability (24.19 %) and the best explant size for somatic embryogenesis was immature embryo with 3 mm length. The six day desiccation treatment caused highest percentage of embryo conversion into plantlet (74.7 %). Wounding increased callus production on explants and number of embryos per explant (20.28), but it did not show any significant effect on percentage of embryogenic calli. Germinated somatic embryos were transferred to pots containing peat-moss. Somatic embryogenesis is an efficient method for the plant regeneration and genetic transformation. However, this method still offers low percentages of plant regeneration, and is perhaps related to the maturation process and high morphological abnormalities of the matured embryos. This study aimed to find some solutions for soybean somatic embryogenesis problems.
M Karami, M Afyuni, Y Rezaee Nejad, A Khosh Goftarmanesh,
Volume 12, Issue 46 (1-2009)
Abstract
Sewage sludge application on farmland as fertilizer is commonly practiced in many countries. Sewage sludge is rich in macro and micronutrients. However, high concentration of heavy metals in sludge may cause pollution of soil, groundwater and human food chain because of toxic metals uptake by crops. The objective of this study was to determine residual and cumulative effects of sewage sludge on concentration of Zn and Cu in soil and wheat. Different levels of 0, 25, 50 and 100 Mg ha-1 of sewage sludge were applied to the soil for four years. To study the cumulative and residual effects of the sewage sludge, applications were repeated on three fourth of each plot in the second year, on one half of plots in the third year and on one fourth of plots in the fourth year. Wheat was grown in the plots. After the fourth year, soil samples from the 0-20 cm depth of the different parts of the plots were taken and analyzed. After harvesting the wheat, roots, stems and grains were separately analyzed for the heavy metal concentrations. Cumulative sewage sludge application significantly (P≤0.05) increased the total and DTPA-extractable concentration of Zn and Cu in soil. Residual sewage sludge in the soil also increased the total and DTPA-extractable concentration of Zn and Cu. Single sludge applications at different rates increased the DTPA-extractable concentrations of heavy metals. In subsequent years with no further sludge application, DTPA–extractable metal concentrations in soil decreased continuously, approaching the levels in the control. However, even after four years, DTPA-extractable concentration of Zn in plots receiving more than 50 Mg ha-1 and Cu in plots receiving more than 25 Mg ha-1 sludge, were still significantly higher than control. DTPA-extractable concentrations of metals were closely correlated with total concentrations. Sewage sludge had a significant effect on concentration of Zn and Cu in stems and grains. Cumulative effects on Zn and Cu uptake by stems were more than residual effects. The results of this study show that cumulative and residual effects of sewage sludge application increased concentrations of micronutrients in soil and wheat.
A.h Khoshgoftarmanesh , A Sanaei Ostovar ,
Volume 13, Issue 50 (1-2010)
Abstract
The objective of this study was to evaluate the possibility of using treated industrial by-products as a zinc (Zn) source and compare their Zn availability and efficiency to ZnSO4. A greenhouse factorial experiment in a completely randomized block design was conducted with corn (Zea mays L.) in triplicates. Treatments included three Zn sources (ZnSO4, IUT-UT in size of < 1 mm and IUT-UT in size of 2-3 mm) at three rates (0, 20 and 40 kg ha-1). The results showed that Zn application both in the form of ZnSO4 and treated industrial by-products significantly (P < 0.05) increased the growth and shoot dry matter yield of corn. Shoot dry matter weight of corn in pots that had received IUTUT was higher compared to those that had received ZnSO4. The highest shoot dry matter weight was produced at the IUT-UT treatment in size of < 1 mm. Increased fertilizer rate significantly (P < 0.05) enhanced shoot and root Zn concentration. However, this increase was higher in ZnSO4 treatment as compared to the IUT-UT treatments. Application of the IUT-UT caused a significant increase in shoot Fe concentration of corn. Shoot and root Cd concentration in all experimental treatments was less than 0.02 mg kg-1. The results showed that IUT-UT can be used as a slow-release Zn fertilizer with low impurity.
H Shirani, M.a Hajabbasi, M Afyuni , A Hemmat ,
Volume 14, Issue 51 (4-2010)
Abstract
Tillage systems and organic manures could affect soil physical and mechanical properties. This study was conducted to investigate the impacts of two tillage systems including conventional tillage by moldboard plowing (plowing depth, 30 cm) and reduced tillage by disk plow (plowing depth, 15 cm) and three rates (0, 30 and 60 ton ha-1) of farmyard manure (FYM) on the soil penetration resistance under corn cropping in a split block design with 3 replications. The cone index (CI) decreased with increase of the tillage depth. It is attributable to soil disturbing and loosening of the deeper layers under conventional tillage compared to reduced tillage. This trend, however, was observed only in the first (after treatments’ application and before cropping) and second (the highest rate of vegetative growth) samplings. In the third sampling (after harvest), there were not significant differences between the CI values under two tillage systems in different soil depths. It might be due to soil re-compaction (approaching the pre-tillage state) as well as disappearance of the tillage effects seven month after commencement of the experiment. In fact, the soil mechanical resistance increased with the time indicating soil re-compaction over the growing season. Adding FYM to the surface layer (i.e. 0-10 cm) of ridge soil resulted in significant decrease of soil mechanical resistance compared to control treatment. The CI decreased significantly in the 30 ton ha-1 treatment up to the stage of highest rate of vegetative grow, but the effect on CI was diminished after harvest. However, the decreasing effects of the 60 ton ha-1 treatment on the CI continued to the harvesting time. There were no significant effects of FYM in the soil deeper than 10 cm from the ridge surface and in all of the layers in furrow. The CI did not decrease significantly in the furrow due to negligible effect of manure application for the inter-row position.
L Omidi, H Dashti, V Mozaffari, A Tajabadipour,
Volume 14, Issue 52 (7-2010)
Abstract
This study was carried out to evaluate the application of zinc and copper sulfate by different methods such as foliar application and deep-placement and time of application on the some quantitative and qualitative properties of pistachio trees. For this purpose, a complete randomized block design experiment with 12 fertilizer treatments and 3 replications at 2 consecutive years was conducted in the experimental garden of Rafsanjan. Treatments included deep-placement of medium amounts (54.2 and 11.1 kg/ha of elemental Zn and of Cu respectively) and high amounts (81.3 and 16.7 kg/ha of Zn and of Cu respectively), foliar application of 0.15 kg/ha elemental Cu in the form of Cu sulfate and 1.8 kg/ha of the elemental Zn in the form of Zn sulfate (34%) at the rate of 1000 liter water on Esfand (late dormant), Farvardin (after flowering) and Mehr (post harvest) . Results indicated that in first year, the maximum yield was obtained with foliar application of Cu on Esfand. Also, qualitative properties such as Split/non split ratio significantly increased by above treatment. The protein content increased with foliar application of Cu on Esfand and Zn on Farvardin by 22 and 16.5%, respectively compared to the control. The analysis of leaf samples, demonstrated that the foliar spray of Cu+Zn on Esfand increased Zn leaf by 119% as compared with control. In second year, yield increased by the foliar application of Zn on Esfand. Also, qualitative properties such as the number of seeds per ounce significantly increased by foliar application of Cu on Mehr. The highest and the lowest rate of split/non-split ratios were observed in treatments of high and low localized placement. The protein content decreased in the treatment of high deep placement as compared to the control. Foliar spray of Zn on Esfand caused the highest increase of leaf Zn concentration and foliar spray of Cu and Zn+Cu in Mehr increased significantly Cu leaf. The results indicated that the effects of treatments on oil content and stem nutrients concentration were not significant on two years. Due to saline and lime effects in the soil in pistachio orchards, soil application of micronutrients had no significant on the the yield.
A. H. Gharehsheikhloo , M. R. Vahabi , H. R. Karimzadeh ,
Volume 14, Issue 53 (10-2010)
Abstract
In order to classify and determine the plant communities in Karkas mountainsides, central Iran, quantitative data of 46 environmental characteristics including climate (12 characteristics), soil (26 characteristics), geology and physiology (8 characteristics), were analyzed based on partial Euclidean distance indicator using minimum variation method. The results showed the clustered separation of studied sites at 68% similarity level with three different growth places. Of these 46 factors, 24 factors (8 climate characteristics and 16 soil characteristics) were effective in this classification at 95% certainty level. Only 24 of these 46 factors were effective in this classification at 95% certainty level. These 24 effective factors were divided into 8 climate and 16 soil characteristics. In another classification, combinational percentage index of 17 plant species were investigated as an effective factor in separating growth place and determining the plant communities. Result of cluster classification indicated that the studied sites cold be classified to 3 habitats.
S. Soltani , L. Yaghmaei , M. Khodagholi , R. Saboohi ,
Volume 14, Issue 54 (1-2011)
Abstract
The temporal and spatial vegetation dynamics is highly dependent on many different environmental and biophysical factors. Among these, climate is one of the most important factors that influence the growth and condition of vegetation. Of the abiotic factors affecting the geographic distribution of vegetation type, climate is probably the most important. Ecological research has traditionally aimed to generalize vegetation types that are assumed to be homogenous. Most of climatic classifications related to bioclimate are focused on limited climatic factors such as temperatue, precipitation and combination of them. As climate is a compound phenomena using limited factors cannot show the climate of a region, and as a result most climatic factors must be considered in bioclimatic classification. Therefore, a climatic study using various climatic factors could reveal the effective factors in distribution of vegetation. In order to determine bioclimatic zones in Chahar-Mahal & Bakhtiari province using multivariate statistical method, 71 climatic variables, which were more important in plant ecological conditions, were selected and evaluated by the factor analysis. The factor analysis revealed that the first three factors which explain %91.8 of total variance among the selected variables were temperature, precipitation, and radiation. According to results and using hierarchical cluster analysis in Ward’s method, bioclimatic classification in Chahar-Mahal province was carried out and 5 bioclimatic zones were found. In addition, Chahar-Mahal province was classified by 4 traditional climatic classification methods (Koppen, Gaussen, Emberger and De Martonne) and those classes were compared to climatic classes obtained by multivariate statistical method. The latter comparison was suggestive of the fact that multivariate statistical method provides a more appropriate classification in comparison to the traditional methods, specially because more dominant vegetation species could be defined for each of the newly described climatic classes. Furthermore, dominant species were determined for each climatic region.
M. Zolfi Bavariani , M. Maftoon ,
Volume 14, Issue 54 (1-2011)
Abstract
Due to low availability of zinc and copper in calcareous soils and the antagonism of these nutrients with each other, the study of their effects on growth and chemical composition of rice seems to have great importance. Also, the relations among different chemical forms of Zn and Cu and plant responses are very important, which can be used in investigation of antagonisms of these nutrients as well. Therefore, by application of different levels of Zn and Cu, their effects on plant growth and nutrient concentration in the plant were studied and different forms of these nutrients in soil were determined. Results showed that zinc application increased plant growth, Zn concentration and total uptake, but decreased Cu concentration in the plant. However, copper application showed no significant effects on the plant growth, but increased Cu concentration and total uptake and decreased Zn concentration in the plant. Also, the results showed an increase in carbonatic, adsorbed and exchangeable Zn forms and exchangeable Cu form by Zn application. Carbonatic form of zinc has maximum effects on concentration and total uptake of this element in the plant. Copper application increased carbonatic and organic forms of this nutrient in soil, and there was maximum correlation between organic form of Cu and its concentration and uptake in the plant
M. Zarei, N. Saleh-Rastin, Gh. Savaghebi,
Volume 15, Issue 55 (4-2011)
Abstract
A greenhouse experiment was conducted in factorial experiment arranged as a completely randomized design (CRD) to evaluate the role of tree indigenous arbuscular mycorrhizal fungi (AMF) species originated from a polluted soil in phytoremediation of zinc polluted soils using maize as a host plant. The experiment consisted of plants inoculated with AMF (G1(Glomus intraradices), G2(Glomus mosseae) and G3(Glomus versiforme)) and G0 as non-inoculated plants and 5 levels of zinc (0, 10, 50, 100 and 500 mg kg -1) in non-sterilized sandy loam soil with three replications. According to the results of greenhouse experiment, the zinc and phosphorus uptake and also the biological yield of maize plants were significantly increased by inoculation with AMF in comparison with non-inoculated plants and also no zinc toxicity symptoms were observed. Uptake, translocation, and phytoextraction efficiency of plants inoculated with G. intraradices was more than the other treatments up to the level of 100 mg kg -1, but at the level of 50 mg kg -1 these amounts were highest in plants inoculated with G. mosseae. The efficicncy of three AMF in zinc uptake was highest at the low level of zinc. In general, under the high soil pollution (500 mg kg-1), G. mosseae was the most effective fungal species in Zn extraction and translocation while G. intraradices had the highest effectiveness for accumulation of Zn in the roots. The overall situation of G. versiforme was mostly between the two other fungal species.
M. Sharifi, M. Afyuni, A. H. Khoshgoftarmanesh,
Volume 15, Issue 56 (7-2011)
Abstract
Micronutrients such as Fe and Zn in adequate level are essential for plant growth cycle and impose a vital role in increasing yields of most agricultural crops. Using organic wastes such as sewage sludge, compost and manure is a proper practice for returning organic matter and some nutrients into the soil, particularly in arid and semi-arid regions. The objective of this study was to determine the effects of sewage sludge, compost and cow manure on availability of Fe and Zn in soil and their uptakes by corn, alfalfa and targetes flower. A completely randomized design with three treatments (sewage sludge, compost and cow manure at 25 Mg/ha) was used. Application of sewage sludge, compost and cow manure significantly increased availabile Fe and Zn of the soil. The application of organic wastes increased the dry matter yield of the plants. Fe and Zn concentration of plants shoots in organic amendments treatments were significantly greater than blank. The highest mean concentration of Fe in plant tissues was obtained in the cow manure and the highest mean concentration of Zn in plant tissues was obtained in the compost treatment.
H.r. Eshghizade, A.h. Khoshgoftarmanesh, P. Ehsanzadeh, M. Kafi,
Volume 15, Issue 57 (10-2011)
Abstract
The growth and fluorescence parameters of chlorophyll in four corn hybrids including two sweet (K.S.C. 403 and K.S.C. 404) and two grain hybrids (S.C. 500 and S.C. 700) were evaluated in response to Fe and Zn nutrition in a nutrient solution culture. This study was conducted in a randomized complete block design with a factorial arrangement with three replications at the Soilless Culture Research Center (SCRC). Corn hybrids were exposed to two Fe levels (5 and 50 µM Fe in the form of FeEDTA) and two Zn levels (0 and 2 µM Zn in the form of ZnSO4). Increasing Fe concentration in the nutrient solution increased F0, Fm, and Fv/Fm values by 48, 96, and 123%, respectively. The fluorescence parameters of chlorophyll were affected by corn hybrid and there were significant differences in F0 and Fv/Fm at 1% level and Fm at 5% probability level among the studied hybrids. Iron deficiency significantly (P<0.05) reduced the root dry weight of all the studied hybrids. Zinc deficiency resulted in a significant decrease in the root dry weight of H403 and H500 hybrids while no significant decrease was found in the root dry weight of the H404 and H700 hybrids under Zn condition. The results showed that corn hybrids varied significantly in their tolerance to Fe and Zn deficiency. Based on the results of plant growth and fluorescence parameters of chlorophyll, the studied grain corn hybrids were more tolerant to Fe and Zn deficiency conditions in comparison with sweet corn hybrids. It seems fluorescence parameters of chlorophyll might be suitable parameters to screen corn hybrids in their tolerance to Zn and particularly Fe deficiency condition.
A. Haghverdi, B. Ghahraman, M. Kafi, K. Davari ,
Volume 15, Issue 58 (3-2012)
Abstract
The objective of current study was to perform screening experiment, (phase zero of response surface methodology) the analysis of salinity and water tensions for spring wheat in Mashhad region and derive water production functions. The experiment was performed in the Research Field of Agricultural Faculty of Ferdowsi University of Mashhad in 2009-2010. Two water sources were selected: saline water (10 dS/m) and water without salinity limitation (0.5 dS/m). A single replicate factorial experiment with four variables and water requirements in different growth stages, was done with each variable having two levels, 20% and 100% of water requirements. The central points of experiment area with two replications were added for estimating the curvature in the fitted response surface. The results showed the water requirements in heading and flowering were the most important variables. The fitted water production functions estimated the yield of saline and non saline plots with correlation coefficients equalsing 0.95 and 0.99. In general, the obtained results proved the efficiency of the screening experiment in identifying the relative importance of variables and excluding the ineffective variables
S. M. Y. Bidaki, M. A. Hajabbasi, A. H. Khoshgoftarmanesh, H. R. Eshghizadeh,
Volume 16, Issue 59 (4-2012)
Abstract
Waste tire rubbers are considered one of the environment pollutants. Increased production of these pollutants has led to more serious consideration of ways to reduce the harms caused by their accumulation in the environment. Therefore, the effects of incorporation of waste rubber crushed particles in two sizes of 1-2 and 3-5 mm and the amounts of 0, 5, 10 and 20 Mg ha-1 in a calcareous soil (0-30 cm depth) on some chemical properties of soil was investigated in Isfahan University of Technology research field (Lavark). This experiment was performed using seven treatments along with a non amended control treatment in a randomized complete block design with three replications in 1387. Eight months after incorporation, soil samples were collected for laboratory analyses. Results of ANOVA tables show that soil pH, electrical conductivity, percentage of total nitrogen and DTPA-extractable concentrations of cadmium, lead, copper and iron were not significantly affected by application of rubber particles. Incorporation of rubber particles into the soil significantly increased soil organic carbon and carbon to nitrogen. Increases in the DTPA-extractable Zn in soils treated with 10 and 20 Mg ha rubber particles in fine and coarse sizes were significant in comparison with the control soil. DTPA-extractable Zn content in the soil treated with 10 and 20 Mg ha 3-5 mm waste tire rubbers particles was about two and three times higher than that in the control treatment, respectively. The results of this study showed that in short-time, incorporation of crushed tire rubbers particles had no significant effect on most chemical properties of the soil but increased the available Zn content. In this regard, further studies to monitor the effects of adding waste rubber crushed particles on organic matter mineralization, plant toxicity and physical properties of soil in long-term are recommended.
M. Pirzadeh, M. Afyuni, A. H. Khoshgoftarmanesh,
Volume 16, Issue 60 (7-2012)
Abstract
This study was carried out to investigate zinc (Zn) and cadmium (Cd) concentration in paddy soil and rice grain produced in central and southwest Iran in relation to soil and plant factors, and their intake in peoples diet was also assessed. Rice crops and associated surface soils (0-30 cm) were collected from 136 fields in Isfahan, Fars and Khuzestan provinces. The result, showed the DTPA-Zn concentration in more than 50% of paddy soils was less than its critical deficiency concentration (2 mg kg-1). The grain Zn concentration in more than 54% of the rice samples was less than 20 mg kg-1. The measured Cd concentrations in paddy soils and edible part of rice exceeded the world health organization (WHO) value in more than 12% of the samples. By considering the average daily rice consumption of 110 g per capita, the Zn intake from rice consumption was estimated about 10% needed for female and male adult. Diet intake analysis did not indicate any excessive dietary intake of Cd when Cd mean of concentrations in rice grain was 0.04 mg/kg, but based on the results of risk analysis, it is more than safely level for contaminated rice.
S. Jafari, Z. Iranshahi , Gh. Fathi, S. A. Syadat,
Volume 16, Issue 61 (10-2012)
Abstract
Cadmium is a toxic element in plant nutrition and is considered as a contaminant of food and feed. A greenhouse experiment was carried out to examine the effects of combined application of cadmium and zinc on responses of wheat on a clay loam soil texture. This experiment was designed in a factorial experiment with randomized complete block design (RCBD) and four replicates per treatment. Three levels of cadmium (Cd 0, Cd 50 and Cd 100 mg kg-1) and three levels of zinc (Zn 0, Zn 50 and Zn 100 mg kg-1) were added to the pot in factorial(9 treatments), and then Chamran seed variety of wheat (triticum aestivum L.) was planted in each pot. The statistical analyses showed that Cd application significantly (P0.01) decreased grain, straw, and total yield, but Zn application increased these parameters significantly (P0.01). Application of Cd separately decreased the grain yield by 61.5 while application of Zn separately increased the grain yield by 36.9. Cd application increased the Cd concentration and uptake by grain and straw as well as total uptake but by increasing Zn application, Cd uptake was decreased by wheat. Cd concentration was higher in straw than that grain, but Zn showed a different trend. Decreasing Zn applications decreased total uptake of Cd from 42.9 in Zn0 to 7.8 mg kg-1 in Zn100 treatment. Although this soil was very calcareous, this characteristic did not control Cd absorbtion.
H. Oroji, A. Golchin,
Volume 16, Issue 61 (10-2012)
Abstract
Potato is one of the most important tuberous crops. To achieve optimum yield in potato, suitable brand and sufficient and balanced soil nutrients are necessary. In order to study the effects of Zinc, Manganese and Copper on potato yield and leaf and tuber concentrations of Phosphorus and Iron, a factorial pot experiment with 32 treatments was conducted in greenhouse of Soil Science Department, Zanjan University, using a completely randomized design and three replications. The study factors were four levels of Zinc(Zn0: 1.14, Zn1: 5, Zn2: 10 and Zn3: 15 mg/kg soil), four levels of Manganese(Mn0: 1.4, Mn1: 5, Mn3: 10 and Mn4: 20 mg/kg soil) and two levels of Copper (Cu0: 0.22 and Cu1: 2 mg/kg soil) which were applied to the soils of planting pots. The results showed that potato yield increased as the soil concentrations of Zinc, Manganese and copper increased to certain levels Soil application of zinc and manganese fertilizers significantly decreased leaf and tuber concentrations of Phosphorus and Iron. Soil application of copper decreased Iron concentration of leaf but not Phosphorus. The highest potato yield was obtained from the treatment of 15, 10 and 2 mg zinc, manganese and copper per kg of soil, respectively.
M. Karam, M. Afyuni, A. H. Khoshgoftarmanesh, M. A. Hajabbasi, H. Khademi, A. Abdi,
Volume 16, Issue 61 (10-2012)
Abstract
The task of modern agriculture is to safeguard the production of high quality food, in a sustainable natural environment under the precondition of pollution not exceeding accepted norms. The sustainability of current land use in agro-ecosystems can be assessed with respect to heavy metal accumulation in soils by balancing the input/ output fluxes. The objectives of this study were to model accumulation rate and the associated uncertainty of Zn in the agro-ecosystems of 3 arid and semi-arid provinces (Fars, Isfahan and Qom). Zinc accumulation rates in the agro-ecosystems were computed using a stochastic mass flux assessment (MFA) model with using Latin Hypercube sampling in combination with Monte-Carlo simulation procedures. Agricultural information including crop types, crop area and yield, kind and number of livestock, application rates of mineral fertilizers, compost and sewage sludge and also metal concentration in plants and soil amendments were used to quantify Zn fluxes and Zn accumulation rates. The results indicated that Zn accumulates considerably in agricultural lands of the studied townships especially in Najafabad (3009 g ha-1yr-1). The major Zn input routes to the agricultural soils (and due to agricultural activities) were manure and mineral fertilizers and the major part of the uncertainty in the Zn accumulation rate resulted from manure source.
A. Madani, A. Lakzian, Gh. Haghnia, R. Khorasani ,
Volume 17, Issue 63 (6-2013)
Abstract
Mycorrhizal fungus colonization of roots may modify plant metal acquisition. In order to study the role of external hyphae of mycorrhizal fungi in metals transferring, the root and hyphal growth zone were separated by 30 µm nylon meshes. Plants were inoculated with G. mosseae and G. intraradices and grown in the root compartment. Six combinations of metals (400 mg of Zn, 25 mg of Cd, 400 mg of Zn + 25 mg of Cd, 50 mg P, 50 mg of P+ 400 mg of Zn + 25 mg of Cd, and no metal kg-1 soil sample) were added to the hyphal compartments. This experiment was carried out as a completely randomized design (CRD) with factorial arrangement in three replications. The results showed that dry shoot weight and phosphorus concentration in mycorrhizal treatments increased significantly compared with non mycorrhizal treatments. of the two fungal species, G. mosseae had more effect on phosphorus concentration in white clover plant. AM fungi increased the Zn concentration in shoot and root of white clover. AM fungi also significantly increased cadmium concentration in root of mycorrhizal treatments compared to non mycorrhizal plants. of the two fungal species, G. intraradices accumulated more cadmium in clover roots. ALL in all the results demonstrated that AM fungi increased phosphorus and Zn transferring to the shoots while cadmium transferring was decreased by stabilizing in the roots.
M. Arabi, A. Soffianian , M. Tarkesh Esfahani,
Volume 17, Issue 63 (6-2013)
Abstract
Physicochemical characteristics of soil, land cover/use and human activities have effects on heavy metals distribution. In this study, we applied Classification and Regression Tree model (CART) to predict the spatial distribution of zinc in surface soil of Hamadan province under Geographic Information System environment. Two approaches were used to build the model. In the first approach, 10% of total data were randomly selected as test data and residual data were used for building model. In the second approach, all data were used to build and evaluate the CART model. Determination coefficient (R2) and Mean Square Error (MSE) were applied to estimate the accuracy of model. Final model included 51 nodes and 26 terminal nodes (leaf). Calcium carbonate, slope, sand, silt and land use/cover were determined by the CART model to predict spatial distribution of Zn as the most important independent variables. The regions of western Hamadan province had the highest concentration of Zn whereas the lowest concentration of Zn occurred in the regions of northern Hamadan province. The results indicate good accuracy of CART model using R2 and MSE indices.
Mahin Karami, Majid Afyuni, Amir Hossein Khoshgoftarmanesh, Mohammad Ali Hajabbasi, Hossien Khademi, Ali Abdi,
Volume 17, Issue 64 (9-2013)
Abstract
Zinc (Zn) is an essential trace element for plants as well as for animals and humans. There is a significant relationship between soils, plants and humans Zn status in a certain agro-ecosystem. The objectives of this study were to assess Zn status of soils in 3 arid and semiarid provinces of Iran and to model the relationship between wheat grain Zn and agro-ecosystem parameters. About 137 soil and wheat samples were collected randomly from the agricultural soils of Fars, Isfahan and Qom and were analysed in laboratory. Modeling the relationship between wheat grain Zn and agro-ecosystem parameters was done using least square based and robust methods. The results indicated that total Zn concentration of soils (range, 21-149 mg kg-1 mean, 75.2 mg kg-1) was in normal ranges. The DTPA-extractable Zn concentrations were below the critical level (0.8 mg kg-1) in 16% of the surveyed fields. The Zn concentration in 80% of wheat grains was sufficient (more than 24 mg kg-1) with respect to plant nutrition (range, 11.7-64 mg kg-1 mean, 31.6 mg kg-1). However, Zn bioavailability for consumers was generally low in more than 75% of the samples. This is because of high phytic acid to Zn molar ratio (more than 15). Soil DTPA-extractable Zn and available P were entered in to most of regression models significantly. Regression analysis showed that most of models fitted to wheat grain Zn concentration and soil Zn and influenced by agro-ecosystem parameters had a weak prediction power, despite their high determination coefficient. This means that factors other than those considered here have a strong influence on the uptake of Zn by wheat in these soils.
