Showing 344 results for Ph
S. Farrahi-Ashtiani, M. Mahdiyeh, I. Nahvi,
Volume 6, Issue 2 (7-2002)
Abstract
In order to increase ketocarotenoid astaxanthin production by Haematococcus pluvialis, the effects of salinity, phosphate deprivation and eosin on growth and astaxanhin production were examined. The experiments were carried out in the growth chamber at 20oC under sterile conditions. The results showed that under salinity, phosphate deprivation and eosin supply, encystment was induced, and at the same time, astaxanthin formation and dry weight increased. Furthermore, by adding histidine to culture medium as a quencher of singlet oxygen, astaxanthin production significantly reduced. Therefore, it can be claimed that accumulation of astaxanthin may be related to antioxidative responses, which increased survival of algal cells under environmental stress conditions.
M. J. Moghbeli Hanzaii, E. Tafazoli,
Volume 6, Issue 3 (10-2002)
Abstract
Alternate bearing is a key factor in limiting citrus production. Chemical controls have proved to be the most effective solution to this problem. Two different experiments were conducted to study the effects of different growth regulators (GA3, NAA, Ethephon) and urea on alternate bearing control in Kinnow mandarin (Citrus reticulata). In the first experiment, GA3 at concentrations of 0, 25, 50, 75 and 100 mgl-1 were applied 3 times during late autumn and early winter 1993 on off trees. Flowers reduced as a result of GA3 application in the following spring but increased in the second spring. Best results obtained with 50 and 75 mgl-1. In the 2nd experiment thinning agents: NAA (0, 100, 200 and 300 mgl-1), ethephon (0, 100, 200, 300 mgl-1) and urea (0, 4, 8 and 12%) were sprayed to the trees on on-year, when the fruitlets were about 0.75-1 cm in diameter. The results indicated that urea had no effect however, both NAA and ethephon were effective on thinning of fruits and control of fruiting. Ethephon at 200 and 300 mgl-1, and NAA at 400 mgl-1 gave the best results.
F. Khajehali, H. Nassiri Moghaddam, R. R. Marquardt, M. Danesh Mesgaran,
Volume 6, Issue 3 (10-2002)
Abstract
Evaluation of uric acid contents of poultry excreta was examined for use in the estimation of apparent protein digestibility. Uric acid was determined either by high-performance liquid chromatography or by spectrophotometric method. A high-pressure liquid chromatographic assay was used with absorbance measured at 285 nm. The method used a reverse-phase system with a C18-bonded column (250*4.6 mm, i.d.). The mobile phase was distilled deionized water. Injection volume was 20 l with a flow rate of 1 ml/min.
Correlation (r) between the two methods for uric acid content of excreta from birds fed diets with different methionine levels was 0.976. The uric acid values were then used to determine apparent protein digestibility. The apparent protein digestibility values, when corrected for uric acid nitrogen, were comparable with those calculated from amino acid analysis.
J. Pourreza, H. Classen,
Volume 6, Issue 3 (10-2002)
Abstract
Effect of supplemental phytase on phosphorus and protein utilization and performance of broiler chickens fed on eight different wheat varieties were evaluated. The phytate contents of wheat varieties were determined. In a completely randomized design with a 8*3 factorial arrangement, 384 day-old commercial male brioler chicks (HubbardPeterson) were divided into 96 groups, four chicks per group. Each of the 24 experimental diets (eight varieties) and three levels of phytase (zero, 500 and 1000 FTU/Kg) were given to four replicates for a period of 21 days. At 21 days of age, chickens of each replicate were weighed and killed by cervical dislocation. Ileal contents were collected and analyzed for P, N, phytate and chromic oxide. Left tibia of two birds in each replicate were removed, pooled and stored at -20oC for bone ash determination. There was a significant (P<0.03) difference in phytate contents between different wheat varieties. Effect of wheat varieties on body weight, feed conversion ratio and bone ash was significant (P<0.05). Added phytase improved body weight, feed consumption, feed conversion ratio and bone ash significantly (P<0.05). Phytase added at 500 FTU/Kg, improved protein digestibility significantly (P<0.01), but increasing the supplement to 1000 FTU/Kg had no further effect. Difference between enzyme levels (500 and 1000 FTU/Kg) was not significant regarding body weight, feed consumption, feed conversion ratio and bone ash. Overall addition of phytase to the diets containing wheat caused an improvement in performance, protein digestibility, and phytase phosphorus utilization in broiler chickens, and can, therefore, be used in diets to reduce feed cost and environmental problems.
H. Seyedoleslami, A. R. Hadian, A. Rezai,
Volume 6, Issue 3 (10-2002)
Abstract
Color sticky board traps are used in pest management for capture of adult insect, to estimate and predict population densities in later stages. Yellow sticky board traps showed high attraction for pistachio psylla. It is important to study these relationships for the right placement of traps. For each of three repetition in one year, four pistachio trees were selected randomly in one orchard. Eight traps were located on two heights and four cardinal directions of each tree (32 traps in each repetition). After one week the adult psylla captured were counted. One and two weeks 1ater, eggs and nymph densities were counted on five leaves in one of the eight positions of each tree on four other randomly selected trees (total 160 leaves each time). Data were subjected to analysis of variance. Coefficient of variation was determined between adults captured in each position and eggs and nymph density counts.
There were significant differences for adult capture and egg density among directions, and in most cases significant correlations were observed between adults captured on each position and total egg and nymph density count on trees. It was concluded that for egg and nymphal density estimation, we can place traps on either of two heights and four directions except on lower east part, but preferably on either height in south direction of the trees . Also suggestions for egg and nymph sampling are given in the text.
A. A. Talebi, E. Rakhshani, S. E. Sadeghi, Y. Fathipour,
Volume 6, Issue 3 (10-2002)
Abstract
Fertility, developmental time and adult longevity of walnut aphid, Chromaphis juglandicola (Kalt.) and its parasitoid wasp, Trioxys pallidus (Hal.) were studied under controlled conditions with a constant temperature of 26±2oC, relative humidity of 60±5%, and 16:8 (L:D) photoperiod. Populations of walnut aphid and parasitoid wasp were reared on walnut seedling in a growth chamber. The mean developmental period, daily fertility rate, and progeny sex ratio were combined to construct demographic life tables. From these tables, intrinsic natural rate of increase (rm), net reproductive rate (R0) and mean generation time (Tc) were calculated. The net reproductive rate (female offsprings per female per generation) and intrinsic rate of natural increase values were 34.69 and 0.278 in walnut aphid and 53.85 and 0.385 in parasitoid, respectively. The mean generation time was 12.75 days in walnut aphid and 10.35 days in parasitoid. Values of rw (weekly multiplication of the females) indicates that T. pallidus is able to multiply 14.81 times per week, whereas the population of walnut aphid multiplies by only 7.001 times in the same period. The population of parasitoids doubled within 1.8 days while the aphid took 2.49 days. Mean pre-imaginal period was 9.14±0.34 days for male and 9.16±0.12 days for female parasitoids on a mixture of different nymphal stages of host. In walnut aphid it was 9.30±0.10 days. The pre-imaginal periods of parasitoid decreases as the aphid host ages. Longevity of adult male and female was 6.17±0.22 and 6.87±0.23 days, respectively, and 12.24±0.94 days for walnut aphid.
M. R. Chakerolhosseini, A. Ronaghi, M. Maftoun, N. Karimian,
Volume 6, Issue 4 (1-2003)
Abstract
Iron (Fe) availability is low in calcareous soils of Iran due to high pH levels and presence of excessive amounts of CaCO3. Overfertilization by phosphorus (P) fertilizers may also decrease Fe availability. The objective of this study was to evaluate the effects of P, Fe and their interactions on the growth and chemical composition of soybean [Glycine max (L.) Merrill] under greenhouse conditions. Treatments consisted of a factorial arrangement of P rates (0, 40, 80, 120 and 160 mg kg-1 as KH2PO4) and Fe rates (0, 2.5, 5 and 10 mg kg-1 as FeEDDHA) in a completely randomized design with four replications. Plants were grown for 8 weeks in a loamy soil, classified as Chitgar series (fine-loamy, carbonatic, thermic, Typic Calcixerepts). Results showed that P application up to 80 and Fe at 2.5 mg kg-1 increased shoot dry matter. Phosphorus concentration, total uptake and P:Fe ratio in soybean increased by P application but decreased by Fe application. Application of Fe up to 2.5 mg kg-1 increased dry matter but decreased it at higher rates. Concentration and total uptake of Fe increased by Fe application but decreased by P application. Interaction of P and Fe had no effect on shoot dry matter. Zinc (Zn) and copper (Cu) concentrations decreased significantly when P was added and manganese (Mn) concentration increased up to 40 mg P kg-1 but decreased at higher rates. Iron application had no effect on soybean Zn and Cu concentrations but decreased Mn concentration at all rates. Prior to any fertilizer recommendations, it is necessary to study the effects of P, Fe and their interactions on soybean under field conditions.
S. Ghadiri Rad, B. Hatami, G. Asadi,
Volume 6, Issue 4 (1-2003)
Abstract
The biology of predatory fly, Leucopis glyphinivora Tanas. was studied under greenhouse conditions. Adult longevity was 8 days and the average fecundity was 35.7 eggs. Incubation period, the 1st, 2nd, 3rd larval instars and puparium duration averaged 2.7, 2.16, 3.48, 5.7 and 8.45 days, respectively. Each generation lasted about one month. The predator efficiency was studied by applying the egg together with the adults of A. fabae at ratios of 1:1, 1:2, 1:4, 1:8 and 1:16 on broad bean. First larval instar was exclusively feeding on small nymphs (1st and 2nd nymphal instars) of aphid. Predator:prey ratios of 1:4, 1:8 and 1:16 decreased the number of prey to 97.9%, 98.8% and 61%, respectively, but ratios of 1:1 and 1:2 were unsuccessful in decreasing the number of preys due to predatory larvae leaving the host plant for searching small nymphs of aphid. As a result, the predatory larvae were efficient merely in a particular range of aphid density and age structure.
S. M. Taghavi, M. Ziaee,
Volume 7, Issue 1 (4-2003)
Abstract
In order to compare Pseudomonas syringae pv. syringae (Pss) isolates from cereals, citrus, stone fruits and weeds by phenotypic characteristics, serological properties and pathogenicity, samples were taken during 1998-1999 in Fars Province, Karaj, Fereidan, Aligudarz and Shahrekord regions. From 350 fluorescent isolates, 47 were negative with respect to oxidase, potato soft rot and arginine dihydrolase tests but positive in hypersensitive reaction (HR) on tobacco, pelargonium, or both. In complementary biochemical tests, these isolates were identified as Pss. Based on LOPAT (levan, oxidase, potato soft rot, arginine dihydrolase and HR on tobacco leaves) tests, the isolates were divided into two groups, but based on the results of GATTa tests alone, isolates were divided into nine groups. Isolates from different hosts showed differences in lipolysis, syringomycin production, ice nucleation activity, lecithinase, pathogenicity, serology and protein profiles.
Sh. Dokhani, J. Keramat, S. Roofigari Haghighat,
Volume 7, Issue 2 (7-2003)
Abstract
Three potato cultivars (Solanum tuberosum L.), spring Marfona, autumn Cosima and Marfona, obtained from Isfahan Province, were stored under different conditions: 4oC, darkness 12oC, fluorescent light room temperature, darkness and room temperature, daylight. Relative humidity of the above stores was 85 to 90%. Analyses were carried out to determine total glycoalkaloids, α-solanine, specific gravity and total solids, during 30 days for the spring cultivar and 90 days for the autumn cultivars in stored tubers. α -Solanine content of each cultivar was determined by HPLC, in mg per 100 g dry weight, at the beginning, the midinterval, and the end of storage periods. Also, amounts of α-solanine in autumn cultivars, which showed the highest levels after storage for sixty days, were determined before and after heat processing for frying and cooking. Data were analyzed statistically by completely randomized design with Duncan’s multiple range test. The results revealed that the amount of α-solanine of the spring cultivar considerably increased under 12oC and flourescent light as compared with the other storage conditions. The amounts of α-solanine considerably increased during the storage of autumn cultivars which were stored at 12oC under flourescent light compared with those stored at room temperature and daylight, room temperature and darkness, and at 4oC and darkness, respectively. The amount of α-solanine decreased due to spring conditions during the storage period for cultivars stored at room temperature and darkness. In spite of the decreasing effect of peeling, before frying and after cooking, frying and cooking processes had no effect on the amount of α-solanine in the samples. Therefore, according to the above results, the most appropriate storage conditions to prevent increasing effect of α-solanine in potato tubers was 4oC in darkness.
Z. Sheikh-Ol-Eslami, J. Jamalian,
Volume 7, Issue 2 (7-2003)
Abstract
Consumption of bread made from flours with high extraction rates is fairly common in western countries and has recently become widespread in Iran. Such breads contain relatively high levels of phytic acid. Phytic acid is present in the aleurone layer of wheat in the form of potassium-magnesium salts. It is carried over to wheat flour and to bread. Phytic acid is known to have chelating properties and to form complexes with bivalent cations (iron, calcium, zinc and so on), thus reducing their bioavailability in humans. In addition, phytate salts can form complexes with proteins, carbohydrates, and fats in the diet, making them unavailable too. In the present study, phytic acid contents of flours ( 3 individual extraction rates and 2 combinations), the dough and two types of popular breads of Khorasan (Lavash & Sangak) made from these flours were determined.
The results showed that the flours had, on the average, 570.37 mg phytic acid per 100 g and that the phytic acid contents of breads were, on the average, 347.31 mg/100g. This indicates that the present baking procedures do not have an appreciable effect on the level of phytic acid recovered in bread.
R. Mohammadi, A. F. Mirlohi,
Volume 7, Issue 2 (7-2003)
Abstract
A symbiotic relationship exists between the endophytic fungi of the genus Neotyphodium and many cool-season grasses. Endophytes can alter the growth as well as morphological and physiological characteristics of the host plant, thereby influencing the persistence and survival rate of infected plants. This study was conducted to evaluate the effects of endophyte on phenotypic characteristics of Iranian tall fescue (Festuca arundinacea Schreb.) and meadow fescue (Festuca pratensis Huds.). The experiment was set up as a completely randomized design with three replications in a factorial arrangement. The first factor was the two plant accessions and the secondary factor was the endophyte-infected and noninfected plants. The results showed that most of phenotypic characteristics significantly altered as a result of endophyte infection in both tall fescue and meadow fescue plants. Results of analysis of variance showed that the influence of endophyte fungus was positive and significant on tiller number, herbage yield, dry crown weight, dry root weight per plant, and crown depth. Also between plant accessions, there were significant differences for dry herbage yield, crown weight, dry root weight per plant, crown depth, and dry matter percentage. Plant by endophyte interaction was highly significant for crown depth and dry root weight per plant. Therefore, eudophytic fungi can be used to improve phenotypic characteristics in these plants.
Z. Rafiei Karahroudi, B. Hatami,
Volume 7, Issue 2 (7-2003)
Abstract
Green lacewing, Chrysoperla carnea (Steph.), is one of the important natural enemies of cotton aphid, Aphis gossypii Glover. In this study, two experiments were conducted on cucumber plant in netted cages (70*70*40 cm) in a greenhouse. In the first experiment, Chryso-bags (special net bags with 360 holes per 2.5 cm2 and 8 cm in width and 12 cm in length) were used. Seven treatments of release ratios included 1:1, 1:5, 1:10, 1:15 and 1:20 (predator: prey) and two control treatments with and without empty bags were compared. The experiment was conducted once in spring and once in autumn. In the second experiment, better release ratios were compared with two methods, Chryso-bag and sawdust as a carrier of eggs. Release ratios were 1:1 and 1:5 (predator: prey). Control treatments included only empty bag and sawdust, respectively. Results of the first experiment showed that the ratios of 1:1 and 1:5 were significantly different in spring, whereas they were not in autumn. The difference was probably due to the difference in temperature. Interaction between treatments and seasons showed that the ratios of 1:1 and 1:5 were not significantly different. In the second experiment, the release ratios of 1:1 and 1:5 in sawdust with each other and with 1:1 in Chryso-bags were not significantly different, while the ratio of 1:5 in Chryso-bag compared with 1:1 in both methods were significantly different. However, leaf necrosis was observed in the sawdust treatment.
S. A. M. Mirmohammady Maibody, A. Amini, J. Khajeddin,
Volume 7, Issue 2 (7-2003)
Abstract
In this study, the potential use of halophyte grasses, Aleuropus littoralis and A. lagopoides, on soil desalinization and lowering soil salinity was investigated under glasshouse conditions. The seeds of two species were collected from Rodasht area in Isfahan and grown with four salinity treatments obtained from different types of collected soils and replicated three times. Electrical conductivities of the four soil treatments were 12.4, 29.5, 43, and 69 dS/m. The results of mean comparison showed that shoot and root dry weight, sodium contents of dry weight and Na/K ratio were significantly different in both salinized species. Both species effectively reduced soil electrical conductivity by 23 to 42.5%. This was mainly due to ion absorbtion, and consequently, from Na+, Cl-, Mg2+, Ca2+ ionic reduction. In general, considerable amounts of ionic absorbtion and total soluble salt secretion through their salt glands appeared to have the most pronounced effects on decreasing soil salinity. Regarding 50% salt excretion by these species, growing these grasses could be a possible way to decrease soil salinity by grazing or harvesting salt crusted foliage from the site.
S. Ayoobi, A. Jalalian, M. Karimian Eghbal,
Volume 7, Issue 3 (10-2003)
Abstract
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.
M. H. Farpour, M. K. Eghbal, H. Khademi,
Volume 7, Issue 3 (10-2003)
Abstract
Gypsiferous Aridisols are of great importance and extent in arid and semi-arid environments. There is a close relationship between soil genesis and landscape positions. This study aimed to determine the genesis and classification of gypsiferous soils and to investigate the relationship between micro-and macro-morphology of gypsum crystals and geomorphic positions in Rafsanjan area. The study area is located in Nough, 30 km north of Rafsanjan with a mean annual precipitation of 60 mm. Seven representative pedons were selected on different geomorphic positions. Physico-chemical, micromorphological, XRD, and SEM observations were performed on soil samples. Rock pediment geomorphic surfaces, that are in fact peripheries of old closed water bodies in central Iran, are the source of gypsum in the area. Large gypsum pendants and microforms of lenticular, vermiform, platy, and interlocked gypsum plates are found in rock pediment. The amount of gypsum and the size of pendants decrease moving down the slope. Lenticular and interlocked gypsum plates are found in a transition of pediment and playa. Puffy ground is observed on the saline surface of playa. Lenticular and vermiform gypsum crystals increase down the slope, but alabastrine gypsum is the most dominant form of gypsum in the playa surface. Large amounts of soft gypsum nodules are found on the rock pediment surface (western slope). In addition, spindle form of gypsum and palycrete bundles are observed in this position. Wind action played a significant role in the genesis and development of soil in rock pediment. A close relationship was found between morphology of gypsum crystals and geomorphic positions.
Sh. Mahmood-Soltani, A. Samadi,
Volume 7, Issue 3 (10-2003)
Abstract
Knowledge of forms of phosphorus (P) is important in the evaluation of soil P status and also in understanding soil genesis and fertility. Amounts and distribution of P in different organic and inorganic fractions were examined in 39 soil samples of Fars province. Soils were sequentially extracted to determine organic P and inorganic P fractions.
Total P with an average of 597 mg/kg soil was lower in the light soils (482 mg/kg) as compared with the heavy soils (690 mg/kg). Organic P constituted considerable portions of TP (27%). Calcium phosphates with an average of 424 mg/kg soil and being comprised of 71% inorganic P was the dominant form of soil phosphorus. Simple regression analysis indicated that there were significant positive relationships between organic P, Ca phosphates and Al-Fe phosphate values with CEC and clay content. Stepwise multiple regression analysis showed that a combination of soil properties such as clay content and equivalent calcium carbonate (CCE) increased correlation coefficients (R). Alghough multiple regression model was significant (at P<0.05), the relative contribution of each soil property in Al-Fe-P fraction was not considerable.
M. Pakdel, J. Pourreza, S. Ansari,
Volume 7, Issue 3 (10-2003)
Abstract
In a 3×3 factorial experiment, 90 72-week-old native breeder hens of Isfahan were kept in cages (one bird/cage). The effect of three levels of dietary calcium (3.27, 2.62, and 1.96%) and three levels of dietary available phosphorus (0.25, 0.20, and 0.15%) on egg production and egg shell traits were investigated. Each treatment contained five replicates of two birds (10 birds per treatment). The experimental diets were fed 8 weeks (from 72 to 80 weeks of age).
Dietary calcium and available phosphorus levels had no significant effects on feed consumption, shell thickness and shell breaking strength. Decreasing dietary calcium or available phosphorus levels (1.96% calcium and 0.15% available phosphorus) caused a significant (P<0.05) linear increase in egg production, egg weight and improvement in feed conversion. The results from this study showed that high egg production, maximum calcium retention in the shell and optimum feed conversion were observed in native breeder hens during late growing period with 1.96% calcium and 0.15% available phosphorus.
D. Ataii, M. A. Sahari, M. Hamedi,
Volume 7, Issue 3 (10-2003)
Abstract
In this study, some physico-chemical characteristics of Iranian tea-seed oil (Lahijan variety) were compared with those of the oils from sunflower seed (Fars variety) and olive (Gilezeytoon variety) in terms of fatty acid contents, peroxide value, iodine value, saponification value, and oil shelf-life. Also the shelf-life of sunflower and olive oils containing 5% and 10% tea-seed oil were compared against control sample shelf-life. Tea-seed oil was found to be suitable and stable in nutritional properties. At a temeprature of 63oC, tea-seed and olive oils were found to have identical shelf-life values, which was higher than that of sunflower oil. Furthermore, the shelf-life of sunflower oil increased when mixed with tea-seed oil.
S. Cheraghi Dehdezi, Sh. Dokhani, M. Shahedi,
Volume 7, Issue 3 (10-2003)
Abstract
Canning of sausage is one of the methods to extend the shelf life of sausage with lower percentage of additives such as nitrite. This method reduces transport and storgae costs, too. The present stduy was carried out in two stages. The first stage consists of preparing sausages with four different formulations in Isfahan Senobar Factory and producing canned sausage. In the second stage, physicochemical and organoleptic experiments were carried out. Canned (214409) and bottled (No. 10-67) sausages were produced and sterilized in autoclave (absolute pressure=2 atm) to give F value = 4 min. Cans and jars were filled with skinless sausage of 22 calibre and brine (2% and 25oC) at a sausage/brine ratio of 1:1. Chemical composition such as moisture, fat and protein were measured according to the standard and AOAC methods. Physical experimets including measurement of texture shear strength were performed in sausage and canned sausage over the 3-month storage period. Factorial experiments in completely randomized design was used to investigate and analyze statistical data in this study. The Duncan’s multiple range test was used to compare data averages. Moisture content increased and sausgae texture shear strength decreased in all formulations as a result of sterilization. Moisture content increased in four canned sausage formulations while protein and fat decreased (by the end of the second month of storage). Also, sausage texture shear strength was observed at this time to decrease. In organoleptic evaluations, four canned sausage formulations were not significantly different in flavor, texture, and color (P<0.01).
