JWSS - Journal of Water and Soil Science

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Methods of seedbed preparation affect establishment, growth and yield of crops via manipulating physical and chemical properties of soil. These effects on wheat-mungbean double-cropping have not been studied in Isfahan. Therefore, the influences of various seedbed preparation methods on soil physical properties and nutrients content and on establishment of mungbean (experimental line 1-61-16) were studied in a wheat-mungbean double-cropping system during 1996 at the Agricultural Research Station, Isfahan University of Technology. Two residue management treatments (burned and unburned) along with four tillage systems (moldboard plow, disk, khishchee and no-till) were laid out in a strip plot design within a randomized complete block design with four replications. Bulk density and penetrability of soil at various depths were not affected by residue management at emergence. However, at the time of flowering, bulk density at 0-15 cm soil depth was lower and soil penetrability at 3-15 cm depth was higher in unburned treatment due to mineralization. Rate and coefficient of emergence of seeds were lower in unburned residue treatment. Soil bulk density at 0-30 cm depths was lower and penetrability at 3-21 cm depth was higher with moldboard plowing at both emergence and flowering time. In addition, lower soil N, P and K content at 0-15 cm depth at emergence and flowering time was obtained with moldboard plowing. Rate and coefficient of emergence were strongly lower in no-till treatment. Based on these results and considering sustainable agricultural goals, incorporating residue with disk tillage might be advantageous under conditions similar to this experiment.

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This study aims to evaluate the present management of border irrigation systems applied to wheat, alfalfa and sugar-beet farms in Boyer-Ahmad and Gachsaran cities in Kohgiloyeh and Boyer-Ahmad Province. Experimental farms included 8 alfalfa farms, 5 wheat farms and 5 sugar-beet farms. The experiments were conducted at different growth stages of plants and customary borders with prevalent dimensions, slopes, and management practices. The relationship between management allowable deficit, moisture deficit before irrigation, and infiltrated depth indicated that in most cases either “deficit irrigation” or “stress irrigation” had been applied. This type of irrigation has positive effects on water use but negative effects on supply of required soil moisture for plants. In the first to third irrigations, measured application efficiencies ranged from 40.8% to 100%, 52.2% to 100%, and 61.1% to 100%, respectively. Graphs of advance, recession, and ideal recession showed the effects of border slope and length on inflow cut time and uniformity of water distribution. Water infiltration curves showed the amount of deficit irrigation. The results showed that weak irrigation management is the result of three parameters: lack of knowledge on the part of farmers about soil moisture conditions and correct time for irrigation, weak irrigation scheduling, as well as an imbalance between available water supply and irrigation requirements which leads to wasting water and reduced irrigation efficiency.

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In order to study the genetic and environmental variability of morphological and phenological characteristics and also to gain a better understanding of the morphological basis of yield variation in soybean, an experiment was conducted at Research Farm, College of Agric., Isfahan University of Technology, in 1996. The experiment was arranged in three augmented designs with 285 lines and 5 control varieties. There were highly significant differences among genotypes for all the characteristics studied. The phenotypic coefficients of variability were greater than the genotypic ones for all the traits although the differences for most of them were small. The highest phenotypic and genotypic coefficients of variation, in order of magnitude, were obtained for number of pods per plant, days to flowering, plant height, height of the lowest pod, and number of lateral branches. Heritability estimates and the percent of genetic improvement for these traits and seed weight were high but for seed yield per plant were low. The lowest coefficients of variability were related to number of seeds per pod and days to germination. The results of stepwise regression analysis indicated that the maximum variation in seed yield could be attributed to the number of pods per plant, number of seeds per pod, and 100-seed weight. Factor analysis in addition to emphasizing the importance of yield components, resulted in four factors which determined 97.34% of yield variation. These factors which were indicators of physiological sink and source, with respect to the traits contained, were named as photosynthetic sink, plant architecture, fixed capital, and weight, respectively. In general, it was concluded that in order to improve soybean cultivars, selection should be in favor of plants with stronger structure, higher number of leaves, nods and pods per plant, and higher seed weights.

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High-yielding rice varieties are prevailing in Guilan Province which is one of the most important rice producing regions in Iran. However, little is known about K status in this region and no suitable extraction method can yet be introduced to the farmers. This experiment was carried out to determine the available K by 15 chemical extractants and also to examine the critical K levels in paddy soils of the region. The treatments included 23 soils and 2 K levels (0 and 300 mg/kg as KCl) in a factorial experiment in a randomized complete block design with three replications.

 Results indicated that K application increased grain and straw yields, K concentration in straw as well as K uptake by rice. High correlation coefficients were observed between MgOAc, H₂SO₄, Morgan and 0.01 M CaC_l2 methods with K concentration in straw (0, 0.83, 0.78, 0.8 and 0.78, respectively) and with K concentration in plant tops (0.79, 0.76, 0.75 and 0.73, respectively). Similarly, high correlation coefficients were observed between the same extraction methods with K absorbed by straw (0.83, 0.82, 0.78 and 0.76, respectively) and with total plant K uptake (0.79, 0.83, 0.74 and 0.71, respectively). Potassium critical levels by different extracting solutions were determined by Cate-Nelson procedure and were 38, 74, 160, 111, 36, 112 and 100 mg kg^-1 for MgOAc, Morgan and Kelowana methods, Texas method H₂SO₄ 0.01 M CaCl₂ and NH₄OAc without and with submergence of soil samples, respectively. In this study, available K was below the critical level in almost 75% of the soils.

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Field capacity (FC) and permanent wilting point (PWP) are important factors affecting irrigation scheduling and field management. FC and PWP can be estimated from some of the soil physical and chemical properties. Pressure Plate apparatus is usually used for determination of FC and PWP, but this is a time-consuming and laborious procedure besides, the apparatus may not be available in many laboratories. Samples were taken from 23 locations in Isfahan and Chaharmahal Va Bakhtiary provinces in central Iran. Soil texture, organic matter and cation exchange capacity were determined. Soil moisture at FC and PWP of the soils were measured with a pressure plate. Simple and multiple regression analyses were used to study the relationships between FC and PWP with sand, silt, clay, soil organic matter and cation exchange capacity.

 Results indicated that FC significantly correlated with sand, organic matter and cation exchange capacity in a stepwise model (r=0.97**). The PWP of soil also correlated significantly with silt, organic matter, and cation exchange capacity in a stepwise model (r=0.95**). Available water capacity (FC-PWP) correlated with sand in a stepwise model (r=0.82**). On the whole, results showed that FC and PWP can be estimated from some soil physical and chemical properties.

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Quantity-intensity (Q/I) curves and their derived parameters provide general information about soil K availability. This investigation was conducted to obtain Q/I parameters and to study the relationships between the Potassium Q/I parameters and the properties of 15 soils from central and northern Iran. Soil samples were equilibrated with solutions containing different potassium activity ratios (AR^k). Changes in potassium concentrations in the equilibrium solution (ΔK) were plotted against activity ratio of K, and Q/I parameters were determined. Correlations between Q/I Parameters and some properties of soils were studied.

The Q/I plots showed the common shapes described in the literature whereas high variations were observed in the soils with respect to AR°, ΔR°, BPC^k and K_x. The potassium activity ratio at equilibrium ranged from 0.005 to 0.532 with an average of 0.02 (mmol L^-1)^0.5. The potassium potential buffering capacity (PBCk) ranged from 4.40 to 76.3 with an average of 16.2 (mmol kg-1) / (mmol L-1)0.5. The readily exchangeable potassium (ΔK°) ranged from 0.007 to 0.737 with an average of 0.25 cmol kg^-1 and slowly exchangeable potassium (K^x) ranged from 0.023 to 0.55 with an average of 0.3 cmol kg^-1. Highly significant linear correlations were found (α=0.01) between PBC^k and CEC (r=0.66), AR° and exchangeable potassium percentage (r=0.76), AR° and solution potassium (r=0.89), and between ΔK° and exchangeable potassium (r=0.79). Because of high variations in physicochemical properties of soils, correlation coefficients between Q/I parameters and soil properties were not very high.

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Evaluation of nutrient status in soil is important from nutritional, environmental and economical aspects. Potassium is a very important plant nutrient not only because of its large demand, but also because of its important physiological and biochemical functions in plant. In order to evaluate K availability and common K extractants in the central region of Isfahan Province, surface soil samples from 26 important soil series were taken, out of which 16 soil samples were selected for further study based on their ammonium acetate extractable K and texture. Available K was extracted from the soil samples by NH₄OAC (4 methods), CaCl₂ (2 methods), NaCl (2 methods), NaOAC, AB-DTPA, Mehlich I, Mehlich III, Morgan-Wolf and HNO₃. A green house experiment using corn (Zea mays L.) variety Single-cross 704 as the test plant with 2 treatments (zero and 150 mg/kg K) and three replications was performed with the 16 selected soils to correlate K uptake with K extracted by different extractants.

 From XRD analysis, the dominant clay mineral was found to be Illite. Based on the amount of potassium extracted by these extractants from the soils the extractants used in this research may be divided into three groups: relatively weak extractants including CaCl₂, Mehlich I and Morgan-Wolf relatively strong extractants including NH₄OAC, NaCl (2N), Mehlich III, AB-DTPA, NaOAC and NaCl (1N), the strongest and weakest extractants in this group were NH₄OAC and NaCl (1N), respectively and finally, a very strong extractant which includes only HNO₃. In each group, the quantities of extracted K showed high correlation with each other. A high and significant correlation was observed between the quantities of K extracted by NH₄OAC, AB-DTPA and HNO₃. The amount of K extracted by 2N NaCl, 1N NaOAC, 1N NH₄OAC, and AB-DTPA was significantly correlated with K taken up by plant and its K concentration. 2N NaCl and 1N NaOAC were selected as the most suitable extractants for K based on their high correlation coefficients with plant uptake (0.79** and 0.72**, respectively) and K concentration in plant (0.86** and 0.85**, respectively). Yield, relative yield and plant response were not significantly correlated with K extracted by different extractants indicating that available K of the selected soils was not a limiting factor for corn growth therefore, it was impossible to determine the critical level of K for corn by the selected extractant.

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In order to evaluate the relationship between SDS-sedimentation value and breadmaking quality of wheat (Triticum aestivum L.), glutenin subunits of different genotypes (foreign and Iranian cultivars) were analyzed by reverse-phase high performance liquid chromatography (RP-HPLC). SDS-sedimentation value was used as an indirect criterion for breadmaking quality.

 Correlation coefficients revealed a closer relationship between low molecular weight (LMW) glutenin subunits and variation in SDS-sedimentation value. Principal component analysis confirmed the presence of association between some of the glutenin subunits and SDS-sedimentation value. Based on the stepwise regression analysis, two LMW and four high molecular weight (HMW) peaks (subunits) were selected which accounted for 70.2 and 18.7% of variability in SDS sedimentation values, respectively. On the basis of the results of the stepwise regression analysis, a discriminant function was developed. The great efficiency of discriminant function in correct classification of completely different genotypes (Iranian landraces and cultivars) showed that the observed relationship between glutenin subunits and SDS-sedimentation value has a genetic basis and the effects of LMW and HMW glutenin subunits on SDS-sedimentation value are additive. Therefore, it seems that this method based on more protein components (rather than only on HMW glutenin subunits) can be used to predict breadmaking quality of wheat against many genetic backgrounds.

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Potassium fixation and release by phillosilicate clay minerals in soils are very important processes influencing the availability of K to plants. This investigation was conducted to determine the potassium fixation capacity and charge characteristics of soil clays of 15 surface soils (0-30 cm) from central and northern Iran. After clay particle separation, both total and tetrahedral cation exchange capacity of soil clays were determined. Tetrahedral CEC was measured after saturation with Li and heating at 300 C to reduce octahedral charge to near zero. Potassium fixation was obtained in both wet (1:10 soil:solution, 16 h on a shaker) and dry conditions (after drying for 24 h at 70°C) using three different levels of added K

The total CEC in soil clays of Isfahan, Char-Mahal and Gilan provinces ranged from 22.1-36.0, 33.0-55.8 and 31.3-47.9 cmol kg^-1, respectively. Tetrahedral CEC in soil clays of Isfahan, Char-Mahal and Gilan provinces ranged from 17.9-4504, 26.2-32.5 and 8.3-23.8 cmol kg^-1, respectively, which consisted of 81.0-98.4, 58.5-95.8 and 24.7-72.5% of their total charge, respectively. The amount of K fixation increased with drying and the level of k added. Mean potassium fixation in soil clays of Isfahan, Char-Mahal and Gilan ranged from 5.42-9.13, 6.63-14.67 and 8.87-10.36, respectively. Mean potassium fixation by soil clays (except for soil clays of Gilan) best correlated with total CEC. In the soil clays of Isfahan, mean potassium fixation correlated with tetrahedral CEC, whereas no correlation was observed in soil clays from other places. The average amount of potassium fixation in clay fractions was in the order: Gilan clays > Char-Mahal clays > Isfahan clays.

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In order to investigate the genetic diversity of morphological traits in 121 genotypes of lima, red and pinto beans, and to study the relation between characters, and to get better understanding of factors affecting the interaction between characters by multivariate analysis, an experiment was conducted in 1997 as a simple lattice design at the Research Station of Agricultural College, Isfahan University of Technology.

High variability was observed among genotypes for all characters studied. The phenotypic coefficients of variability were greater than the genotypic ones for all the traits. Among the characters studied seed yield, number of pods per lateral branches and main stem, length of lateral branches and main stem, number of nodes per lateral branches and main stem, 100-seed weight and number of lateral branches had the highest genotypic and phenotypic variability, while days to maturity had the lowest variability. Traits relative to lateral branches were more variable than the same traits in the main stem. Factor analysis for all the genotypes and, separately, for lima, red, pinto, determinate and indeterminate genotypes revealed 4 factors which justified more than 78.4 percent of the total variation. The results of the analysis based on all the genotypes showed that the first factor was mostly correlated to days to maturity, length of main stem and lateral branches, number of nodes per main stem and lateral branches, which was named “vegetative factor”. The second and third factors had the highest correlations with number of pods per main stem and lateral branches, number of seeds per pod in the main stem and branches and 100-seed weight, which were named “yield component factors”. The fourth factor showed the highest correlation with number of lateral branches and was named for this trait. The first and fourth factors were related to vegetative growth characteristics and physiological source. The second and third factors were related to physiological sink. On the basis of stepwise regression analysis, number of pods per lateral branches was the most important component of yield, and number of pods per lateral branches and main stem had the next following ranks. Number of pods per lateral branches and main stem had the highest relationships with yield.

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In order to determine the relationships among the different traits of onion and to study the direct and indirect effects of these traits on bulb and seed yield, an experiment was conducted in 1998 at the research farm of Isfahan University of Technology. Results showed that phenotypic and genotypic correlations were similar and bulb weight showed the highest and lowest coefficients of correlation with bulb diameter and number of days to emergence, respectively. Results of stepwise regression analysis showed that leaf width at 25% of its length from the neck, leaf length, and leaf dry weight were the best estimators for leaf area bulb diameter, bulb length, plant height and number of days to maturity were the most important determining characters for bulb yield variation. Number of fertilized florets was the best determinator of seed yield and bulb weight, while diameter and volume were the best describing characters for the number of meristems on the basal plate. Path-coefficient analysis revealed that bulb diameter showed the highest direct positive effect on bulb yield and the indirect effect of plant height through bulb diameter on it was of prime importance. Number of fertilized florets per plant and number of inflorescence per plant through the number of fertilized florets showed the highest direct and indirect effects on seed weight, respectively.

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Rice bran is the most important by-product of rice milling. It is a valuable source of edible oil in most rice producing countries. Rice bran oil is used in babyfood, biscuit, poultry, fish and farm animal feeds. The storage of rice bran without 'heat processing will result in hydrolysis and auto-oxidation of lipids, and to its decreased physicochemical, organoleptic and nutritional quality. Rice bran is rich in carbohydrates, free amino acids, lipids and different enzymes. The enzymes have destructive effects on the quality of rice bran components. Heat processing is an effective method to reduce the microbial and enzymatic activity of bran.

This study was carried out using a factorial experiment by completely randomized design with three replications to investigate the effect of heat treatment and storage time on rice bran crude oil properties. The parboiling treatment was effective on the rice kernel strength. The bran produced from parboiled rice milling had lower endosperm components. This type of bran had a lower starch but a higher oil percentage. The results of color of rice bran oil samples determined by Lovibond showed that the oil from parboiled rice bran before and during storage had better color than the other samples. Iodine value of bran oil from parboiled paddy decreased during the storage period. The results from studies on fatty acid composition of oil samples determined by gas chromatography (G.C.) showed that the quantitative trend of fatty acids of the control sample remained the same as that in the rice bran samples with the treatment process.

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Investigation of paleosols plays a great role in paleoecological and paleoclimatological studies. They are also important in soil survey and planning, as they exhibit characteristics different from younger soils. Paleosols are those soils which formed under conditions different from present ones, and are either buried within sedimentary sequences or those which lie on persisting surfaces. Although such soils are widespread in central Iran and Zagros Zone, they have not been studied adequately. Paleosols are identified by different parameters such as morphological, physical, chemical, mineralogical, and micromorphological characteristics. In this study, morphological, physical, and chemical properties of three paleosols from Isfahan and Chaharmahal & Bakhtiary provinces were investigated. The profiles were on different landforms including alluvial fan, dissected old plain, and old lagoonal deposits. Soil profile in Segzi site, on old lagoonal deposits, had a very dark and thick layer at a depth of 45-60 cm containing some macrofossil shells. This shows that this area was covered by brackish water during the early Holocene. In Sepahanshahr profile, presence of strong clay coating and high concentrations of CaCO₃ indicates a wetter environment in the past than the present conditions with a precipitation of only 100 mm. In Emam-Gheis profile, a buried paleosol was identified with strong clay coating and free CaCO₃ horizons that shows more humid conditions. Evidences obtained from the three paleosols studied indicate that effective moisture in central Iran and Zagros regions during Late Pleistocene had been higher than its present levels.

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To determine the effects of salinity and boron excess in irrigation water on relative growth rate (RGR), net assimilation rate on a leaf weight basis (NAR), and leaf weight ratio (LWR) of pistachio, three pistachio rootstocks (Badami -Zarand, Sarakhs and Ghazvini) were used. Rootstocks were grown in soil in eight-liter polyethylene pots. Sodium chloride treatments were 0, 75,150 and 225 mM NaCl and boron treatments were 0, 20 and 40mg liter^-1. Treatments were applied to the one-year old pistachio rootstock seedlings in three-day intervals with irrigation water. Some plants were randomly selected and destructively harvested before (day 0) and after applying treatments (30 and 60 days after treatments started). Growth and physiological characters were then measured as follows: number of leaves, leaf area, plant height and root length, fresh and dry weights of stem, root and leaf, proline accumulation in the leaf, total chlorophyll, and leaf relative water content (RWC). Results indicated that relative growth rate decreased with time for all treatments and in all rootstocks. Salt treatment significantly reduced both RGR and NAR, whereas LWR showed no significant differences. In all rootstocks, NAR, but not LWR, was significantly correlated with RGR, indicating that NAR was an important factor underlying the salinity-induced differences in RGR among the pistachio rootstocks. Salinity did not affect leaf water potential (ψ), chlorophyll content, and Fv:Fm ratio but increased NaCl concentration and time correspondingly increased proline accumulation in leaves. In addition, Ghazvini rootstock accumulated more proline compared to other rootstocks and was more resistant to salinity treatments. Different boron treatments did not show any significant effect on growth rate nor on measured parameters after two months of exposure to treatments.

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Russian Wheat Aphid (RWA) is a serious pest of wheat, barely and other small grains in cereal-producing regions of the world. The use of resistant cultivars is an effective management strategy to control this pest. In this study, 15 lines and 13 cultivars of durum and bread wheats along with two resistant and susceptible controls were used to evaluate their reaction to RWA under greenhouse conditions, using completely randomized design with four replications. Three seedlings at each plot were considered as an experimental unit. Five aphid nymphs (4-5 ages) were placed on each plant at 1-2 leaf stage. Leaf rolling and leaf chlorosis percentages were measured 21 days after infesting and used to screen the genotypes. Despite the relatively high linear correlation between two resistance components, leaf rolling and leaf chlorosis, estimated as 80%, analysis of variance indicated significant differences among genotypes. Eight durum lines DW9, DW14, DW4, DW2, DW7, DW8, DW12 and DW3 and one bread wheat cultivar (Azadi) were significantly more resistant than the resistant control (Halt). One durum line (DW13) and two bread wheat cultivars (Shiroodi and M-75-7) had higher leaf rolling and leaf chlorosis than the susceptible control (Sholeh). So they were selected as the most susceptible to the biotype of D. noxia. under study. Orthogonal comparison showed that durum lines were more resistant than bread wheat cultivars. These results were confirmed by Cluster Analysis based on leaf rolling and leaf chlorosis.

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The vast pastures and agricultural development plans for dry farming and irrigated farming in Khuzestan Province depend on rain. This requires availability of annual precipitation prediction models to be used in the management decision-making process. In this research, the long-term daily precipitation data from 15 rain gauge stations in the study area were collected for study and a relationship between the early fall season precipitations of 42.5 mm (t_42.5) and the annual precipitation was obtained. The results showed that the relationship was an inverse one such that the later the fall precipitation occurred, the greater the annual precipitation would be. To increase the coefficient of determination in the models, climatic variables such as Persian Gulf sea surface temperature and geographical characteristics (longitude, latitude, altitude, and long term mean annual precipitation) were used. Except for the long term mean annual precipitation and altitude, other variables did not increase the coefficient of determination. The final simple model found is as follows: P_a=184.787-1.891t_42.5+0.855P_m , R²=0.704 where, P_a is the annual precipitation, t_42.5 is the time from beginning of fall season for 42.5 mm of precipitation, and P_m is the long term mean annual precipitation.

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An approach for regional low flow frequency analysis is to use multiple regression techniques for obtaining relationships between low flows with specific return periods and catchments characteristics. In this paper, this method has been used. After single-site frequency analysis for 20 stream gauging stations, homogeneity test was performed. Regional relationships between low flows with return periods 2 , 5 , 10, and 20 years and catchments characteristics were derived. For this purpose, catchment area, mean elevation, minimum elevation, shape factor, main channel length, length of main chanel from catchment centroid to outlet, forest area, mean annual rainfall, and mean catchment slope as model inputs were examined and cachment area, mean elevation, and mean catchment slope entered to the models. Finally, the mean relative error of models for different return period, 2, 5, 10, and 20 years, was computed 41.1, 41.3, 45.0, 47.2 percent, respectively that in comparison with other studies, it displays smaller errors.

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Satellite data use is finding global applications because they provide repeated cover, broad information, high electromagnetic spectral resolution, and software-hardware compatibilities. This study aims to evaluate of the Landsat TM data capabilities in land-use mapping of Bazoft River basin (Chahar Mahale Bakhtiary Province). Six spectral bands of the Landsate TM were employed to produce land-use map of the Region. The date of image acquisition was May 5^th, 1998. Performance of the geometric correction completed with RMSE= 1.008 pixels. Various image enhacement methods (e.g. FCC, filtering and Vegetation Indices) were used to study the different land-covers. Field investigations were carried out using a GPS, 1:50000 scale topographic map and false color composites images. Heterogeneous land-use units were studied in 62 sample sites estimating percentage of vegetation cover. A regression analysis was performed between percentage vegetation covers and vegetation indices values of NDVI, RVI, SAVI, DVI, TSAVI₁, NRVI and MSAVI₂. Results show that NDVI, SAVI, TSAVI1, NRVI and MSAVI₂ have high correlation coefficients. But RVI, DVI and PVI have low correlation coefficients. The resulting values of vegetation cover were density sliced to produce the land-cover map. After supervised classifications and density slicing of Vegetation Indices, classifacation accuracy was assessed and, finally, land-use map of the study area was produced with Hybrid classification method. Supervised classification with maximum likelihood method was the best technique for land-use mapping in the study area the total Kappa index was %87. In general, detection of some land-use classes through single date TM data is not feasible, these include: scattered forest trees with cultivated understory, annual grasses, and fallow lands. Also TM digital data are incapable of distinguishing small and separated rural constructions or soil-covered routes.

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Analysis of transgenic plants is very important in gene transfer programs. In this research, the second generation (T₁) of transgenic brassica napus which was transformed by antisense of Glutamine synthetase (GS) gene was studied from the view of total soluble protein content of leaf, total chlorophyll and protein patterns (SDS-PAGE) using seeds of Brassica napus .Protein concentration was determined by a calorimetric method described by Bradford method. Chlorophyll (a, b) and carotenoid contents were determined by spectrophotometry. The total soluble protein content of Brassica napus leaves increased from YG stage, reached a maximum level during MG₂ and, after this, decreased with the progress of SS stage. Comparison of the total soluble protein between different treatments showed the highest level in the A₂ plant and the least in the A₆ plant. Comparisons with chlorophyll a and b were not significant between different treatments, but different stages showed significant differences with maximum and minimum levels obtained in the MG₁ and SS, respectively. Protein patterns were also studied using SDS-PAGE method. No new band was recognized in the MG₁ stage, but the density of some protein patterns was shown in YG and MG₂ stages. In YG stage, differences were seen among the A₅, A₃, A₄ and A₆ with W.T on 41 KDa weighty position and also between the A₁ and A₂ with W.T treatment on 23/6 KDa. Considering the molecular weight GS₁ subunit of glutamine synthetase (41 KDa) and the similar conditions in growth, protein extraction and macro molecular analysis in transgenic and control plants, we can tell that the difference shown in transgenic plants are probably due to the effect of the antisense of glutamine synthesis gene in this plant.

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Low calorie salad dressings are oil-in-water emulsion products, in which the oil content has been substantially decreased. This decrease, however, is accompanied by reduction in the viscosity hence, an undesirable texture. To overcome this, oil replacers are generally used. In this research, maltodextrin and xanthan gum were used to replace part of the oil in the production of two kinds of salad dressings mayonnaise and three Italian salad dressing. Various formulations of these products with varying amounts of oil, maltodextrin and gum at different temperatures were produced. Viscosities in the range of 50-140 Pa.s for mayonnaise and 2-15 Pa.s for Italian dressing were accepted as positive criteria and samples in these ranges were chosen for organoleptic and microbial tests. The results showed that in the formulation of mayonnaise, simultaneous increase in the amount of oil, maltodextrin and gum created a high viscosity, but the temperature did not play any significant role. In the Italian salad dressing, the increase in the amount of gum was accompanied by development of pseudoplastic characteristics which was not desirable, hawever, the effect of temperature on providing acceptable texture was found to be important. Although the formulated mayonnaise enjoyed a fairly acceptable quality, the Italian salad dressing samples, were ranked superior to the common Italian salad dressing available in the Iranian market. .