Daneshvar Medicine: Basic and Clinical Research Journal
Year:2001 | Volume:8 | Issue:31|Papers Count:22

Chemical composition and antimicrobial effects of essential oils of Thymus x-porlock and Mentha longifolia were studied. Disc diffusion method was conducted to evaluate the zone of E. coli and S. aureus growth inhibition at various concentrations of the essential oils. The antimicrobial effect was also studied against three different concentrations of microbial suspension to find out MIC (Minimal Inhibitory Concentration) and MBC (Minimal Bactericidal Concentration). The essential oils from Thymus x-porlock and Mentha longifolia were bactericidal against both the micro organisms. Gram negative bacterium, E.coli, was readily affected as compared to S. aureus. Chemical composition of the essential oils were analyzed by Gas Chromatography and Mass Spectrometry (GC and GC/MS). Five common monoterpene compounds at various concentrations were found in both the oils Viz; α-pinene Limonene, Linalol, Sabinene and Myrcene.  α-pinene and Limonene seem to have exerted antimicrobial effect in both the plant extracts. Presence of α-pinene seem  to enhance the antimicrobial effect of Thymus x-porlock.The major compounds found in the essential oils of Thymus x-porlock were 1,8-Cineole (54.52%), Sabinene hydrate (5.03%) and thymol (7.89%) and those of Mentha longifolia were Piepritone (43.96%) and Trans-Piperitol (12.5%). Limone of Mentha longifolia was at the highest level of 13.73 percent among monoterpene compounds. The study shows greater bactericidal effect of Thymus x-porlock essential oils. With a view to the increasing limitations of the use of chemical antimicrobial agents and development of drug resistance, it seems necessary to switch onto a new harmless antimicrobial agents from natural sources.

30 plots (0.1 ha.) were selected in three different altitudes (400-600m, 600-800m and 800-1000m) in Lajim, North of Iran. In every macroplot 9 microplots (2m2) and 1 microplot (l00m2) were selected. In macroplots the total of trees, vegetation layer, soil condition and the factors such as deforestation and physiographic and in microplots the quantitative and qualitative natural regeneration of all trees especially hornbeam were studied. In this investigation after analysing the data the results were as follow:Generally, the frequency share of tree species is Carpinus 44%, Fagus 24%, Parrotio 14%, Diospiros 9% respectively. The mean percent frequency of Carpinus regeneration is about 56% and the other tree species is 44%. The altitude, slope, aspect, crown cover and vegetation layer did not have considerable affect on hornbeam regeneration. In destructed Carpino-fagetum community, hornbeam replaced beech. Soil scarification increased hornbeam regeneration. Increasing drought also decreased hornbeam regeneration. In Parrotio -Carpinetum community, hornbeam regeneration was remarkable. Besides that, due to human being and stock, the regeneration of superior species were decreased and the inferior and invading species, such as Parrotio persica and Diospyrus lotus were increased.Because hornbeam, by its leaves, produces high quality humus layer, improving the soil condition, and provides an important role in treatment and prunning of the dominant species and produce long fiber for pulpwood, therefore the encouragement and development of this species should be highly considered. In Parrotio-Carpinetum communities by implementing the appropriate silvicultural practices, particularly the encouragement of natural regeneration, the adaptable species, especially hornbeam can replace the inferior tree species. Thus, in addition to the development of these communities, the conservation, biological and economical values can be enhanced.

A major step in the design and evaluation of furrow irrigation system is the determination of infiltration function. The purpose of this study is to compare, infiltration measurement results using double ring and inflow-outflow method following consecutive irrigation events. Study of bulk density variation after each irrigation was another aim of this investigation. Experiments were conducted on a site near agriculture faculty of Shahid Chamran University. Results indicate that correlation coefficient in the first irrigation period is low in comparison with the others periods. Cumulative infiltration is reduced in the second irrigation in comparison with the first irrigation 180 minutes after irrigation started. Also cumulative infiltration is reduced in the third irrigation in comparison with the second irrigation. During the fourth irrigation, cumulative infiltration increased in comparison with the third irrigation which was due to the weed growth in thefurrows. Results show that calculated infiltration rate using inflow-outflow method is 4.4 times greater than double ring method. The results also show that for short time periods (less that 180 minutes), Kostiakov method is in a better agreement with Kostiakov-lewis method. Cumulative infiltration was shown to be higher using Kostiakov-lewis method in comparison to actual measurement for long time periods (more than 180 minutes).

In the present study usable states of point frame for plant cover measurement in grass and shrubland communities namely: point frame application inside the quadrat, point frame application without quadrat and application without quadrat with 90°, 45°,30° angles have been compared. Based on accuracy, time consumption and ease of work the best states of cover measurement were determined. For this purpose, the cover obtained from each state was compared for each vegetation type and communities using one way analysis of variance. All analysis were conducted using SPSS for windows. The results showed that fewer single point were required in a long continuous transect than groups of pins in quadrat of frame for comparable variance. In addition, point frame application without quadrat was less time consuming, more convenient and simpler to use than point frame application with quadrat.In shrubland community, the point frame application with 90° angle was the best state.In grassland community specially grass vegetation from, the point frame application with 45° angle was the best state.

Growth analysis will help to achieve a better understanding of the effects of different environmental factors such an weeds on the yield of crops. To examine the above hypothesis an experimental research was conducted on soybean in Eahi-Mahaleh Reseach Station in Golestan Province in 1997. Treatments were divided in two groups. The first group comprised of soybean plots which were kept weed infested up to V1, V3 , V5,V7,R1, R4 and R8 growth stages and the second group were kept weed free up to the same growth stages. Fourteen treatments were arranged factorially in a complete Block Design with four replications. Seed yield, number of pods per plant, number of seeds per pod and 1000 seed weight was measured. Growth indices such as Leaf Area Index, Crop Growth Rate and Leaf Area Ratio were also calculated.Number of pods per plant was the most important yield component which showed a strong positive correlation with seed yield. There was little reduction in number of seeds per pod and 1000 seed weight due to weed competition. Seed yield was affected by weed competition and was significantly reduced as weed competition continued to the later stages of soybean growth. Leaf Area Index and Crop Growth Rate significantly reduced as weed competition continued, but Relative Growth Rate, Net Assimilation Rate and Leaf Area Ratio were not affected by weeding time. The changes in growth characteristics well defined changes in soybean yield.

Root knot nematodes are among the most important groups of plant pests and is a major cause of crop loss. In this research, the control of nematode of tomato in greenhouse was conducted using tobacco dust as a bio-nematicide. I.M.P. diagnostic keys and some other common references were used to accurately identify species and the race of nematode. Experiments were carried out using complete randomized block design with 5 replication and 7 treatments at different rates of 0, 5, 10, 15, 20, 25 and 30 gr/kg. Soil shoot lengths, root fresh weights and root gall index were measured in all treatments. Results showed that 20gr. tobacco dust per kg soil was the best. The experiments were conducted over a two year period. The results showed that about 100gr per plant was the most effective treatment and the striped application at transplanting time proved to be recommendable.

Two submerged weeds, Potamogeton perfoliatus L. (clupsed pondweed) and Myriophyllum spicatum L. (water milofoil) were grown in laboratory tanks in single and mixed-species cultured in combinations of low and high densities at fertilized and unfertilized sediments. Biomass of individual shoot root, shoot length, shoot number, root to shoot ratio, the nitrogen content of plant biomass, and the suppression coefficient for each species were determined after 12 weeks. Above-ground biomass showed virtually no differences due to initial planting density. Above-ground biomass alone indicated that the species were relatively similar to one another when grown in unfertilized sediment. Nonetheless, mixtures were dominated by Potamogeton when grown on this sediment. Differences in grown between the species were exaggerated by increased sediment fertility, with mixtures again dominated by Potamogeton. Both species allocated more amount of biomass to above-ground structures when grown on nitrogen-rich sediments, compared to growth on nitrogen-poor sediments. However, Potamogeton accumulated substantially more below-ground biomass than Myriophyllum on both sediments. Experimental results showed that Potamogeton shoots were significantly more N-costly than Myriophyllum shoots. For below-ground tissues Potamogeton was significantly less costly than Myriophyllum.Experimental results showed that, Potamogeton maintained a very high suppression coefficient under both sediment conditions. Myriophyllum showed considerable suppression of growth under presence of potamogeton especially at nitrogen-poor conditions. On a per plant basis, one Potamogeton on unfertilized and fertilized sediment were equivalent to 4 and 2.57 Myriophllum, respectively. The obtained results have led us to further understand the growth strategies of such nuisance species in different sediment and plant density. With this knowledge, management might be more easily practiced and natural community changes more accurately predicted.

Ecological capabilities (environmental characteristics such as soil, slope and its direction, microclimate and elevation which shows potential of forest) of Iranian conifers forests were evaluated. As such, cypress "Cupressus sempervirens", forest sites in Hasan-Abad, Chalus and Zarringol, Gorgan were studied. For this evaluation trees distribution, natural regeneration and vegetation were considered.After obtaining the maps of slope, geographical aspect, elevation and soil, the ecosystem unit's maps were drawn. Inventory was performed in 2500m2 sample plots. For analysis of data, basal area, trees distribution in trunk diameter classes, number of trees per hectare, height curve, biodiversity indices and regeneration were prepared. The results show that Hasan-Abad cyprees forest is an unevenaged forest which has some problems in natural regeneration over the past 30 years. However, zarringol cypress forest has a good natural regeneration from the conservation point of view. Cypress is compatible with calcic soils but the sandy soil has not a suitable capability for this species. The best site situation for this species is north geographical aspect, with elevation less than 700m, low slope and soil deeper than 1m. On the contrary the worst situation for cypress is south geographical aspect, high slope, with shallow soil and elevation over than 700m.

In order to survey the effect of different environmental factors on oak (Quercus castaneifolia L.) natural regeneration, 20 macroplats of 1000m2 were selected randomly at different sea level in Sourdar forests (north of Iran). In each macroplat,9 microplots of 12.5 square meter (in total 180 microplats) were selected at 4 different directions. The characteristics measured included: cutting method, altitude, diameter at breast height, total height, crown length, crown form, stem quality, crown canopy, steep, direction, ground vegetation, soil, species, number and quality of seedling and sapling.The results of the present research showed that crown canopy and crown asymmetry did not have a significant relationship with oak natural regeneration. There were no remarkable relationship between healthy mother tree and unhealthy oak regeneration, because livestock and human had substantial effect on unhealthy seedling and sapling. As a whole, the best oak regeneration occurs in low elevation parts, southern aspects, more slightly slopes and middle age phases. Likewise, oak had better regeneration in deep, humid and clay soils.

A study was conducted to determine the critical period of weed control in sugar beet (Beta vulgaris L.) during 1997 in Shahrood District. Treatments included weed free and weed infested periods up to 14, 28, 42, 56, 70, 84 days after emergence and to the end of growth season (Weed free and Weed interference, respectively). Treatments were replicated four times in a complete randomize block design.Results showed a critical period of 10 to 108 days after emergence for weed control (with 5% allowance for yield reduction), for root yield and 11 to 128 days after emergence for sugar yield. Weed free period up to 14 and 42 days after emergence reduced weeds dry weight by 47% and 80% compared to weedy check respectively.Weed infested up to the end of growth season reduced root yield by 91.5% and sugar yield by 94.5% compared to weed free check.

In this project the concentration of lead in lettuce and soil samples of the adjacent farms of Behshahr-Amol highway have been studied. For Determination of lead in lettuce and soil samples of these farms, with due attention to the natural altitudes of the studied area, two stations at area near the mountain, and two stations at an open area (field) were selected. At each station, with the distance of 10, 20, 30, 50, 100 and 150m from the main road, the lettuce and soil samples were collected. All the samples were analysed by using international standard method and their heavy metal content were determined by using Atomic Absorption Spectrophotometer (AA.s).The results of the statistical analyses (Lsd exam) stated that, there is a good and meaningful variation (With %95 assurity level) between the lead content of lettuce and soil samples of 10, 20 and 30m distance, with those of having 100 and 150m distance from the main road. In other words, the concentration of lead in lettuce and soil samples at marginal area of highway are much higher than those of having higher distance from the highway and the concentration of lead reduces by distance from the highway.The results of the F-test on the effect of mountain on accumulation-of lead in agricultural land, stated that, there is a significant variation with %95 assurity level between the mean concentration of lead content of the lettuce farms at two compared areas (mountain - field).This means that the mountain have a good effect to the accumulation of lead produced by the traffic transport means.

In this research, the control of tomato root knot nematode was conducted using neem cake at different rates. First, the species and race of nematode was identified by employing diagnostic keys. Then, with 5 repetition in complete randomized block design neem cake was used at seven treatments (0, 0.5, 1, 2, 3, 4 and 5gr per kg of soil). Statistical analysis on mean treatments showed that treatment with 2gr/kg soil economically was effective in growth rates and reduction in gall index.

In this investigation, the effect of crude oil on morphological aspects, development of Ovules and pollen grains and seed germination of Brassica napus L. (Brassicaceae) are studied. The plants potted under equal conditions were treated with 0.8% and 1.6% concentration of crude oil (by spraying, addition to the soil or both) at the end of vegetative phase. Upon comparison with the control groups, the treated plants showed a considerable reduction in growth, leaf chlorosis, necrosis and a total yield reduction.Exposure to 1.6% mixture of crude oil (in the use of both ways) on plants, caused a reduction in the number of pollen grains and ovules while using different concentration of crude oil results in variation of these as well as on stem anatomy. Comparing with the control groups, the percentage seed germination showed a considerable reduction while length of hypocotyl and the rate of seed germination under 1.6% concentration was more than 0.8%. In some cases, harmful effects of crude oil was not directly correlated to concentration.

Anatomical structure of glume epidermis in several populations of Aegilops belonging to 12 species distributed in Iran were studied. The features of abaxial epidermis of glumes as well as coastal and intercoastal parts of each species were compared. The relationships between species and affinities were determined on the base of observed structures. Abaxial epidermis shows some differences among studied species. Moreover, the number of epidermal silica cells shows variation among the species. However, Anatomical structure of glume epidermis does not seem to provide useful evidences for definitive separation of these taxa.

In processing of agricultural products such as potatoes, corn, sugar beet, fruits and vegetables and their alied industries, high quantity of clean water are consumed. The used water creates some volume of wastewater which contains considerable amounts of organic materials and biogenic metals and therefore requires different treatment procedures. Uncontrolled discharge of this wastewaters threatens the surface waters, ground waters, as well as soils. Because of their considerable volume and suitable quality, they could be used in irrigation of the farmlands. In this study, chemical quality of some of food industries wastewater was determined and their potential use in irrigation of agricultural crops was investigated. Considering all of favorable conditions for reuse of waste water including: limited water recourses, climatological situations, periodic drought, increasing population growth and so on in this country, findings of this study are going to be used for overcoming problems due to water shortage. It is also important in control of environmental pollution due to wastewater discharge.

Water from 6 station in Neka, Tajan, and Gorgan estuaries and their adjacent sea waters at south eastern part of the caspian sea were collected and analysed for determination of oil and its derivative compounds such as polycyclic aromatic hydrocarbons and phenolic compounds. FT-IR (Bruker - IB 588) TOC analyser (Rosemount - Dorhaum DC 1901), and LS-5 Luminescence Speclrometer (Perkin-Elmer) according to the ROPME and ASTM standards have been used. Results have indicated existence of oil, PAHs and phenolic compounds in the range of 0/34-1/56mg /I, 0/4-0/6µg/l and 0/5-10/5µg/l respectively.

Pollutants of various type and nature including heavy metals find their way into the Haraz River. Cadmium (Cd) and lead (Pb).concentrations and their fluctuations in the tissues of several fish species in the lower part of this river were investigated. The fish samples were caught by using electroshocker. Tissues from gills, muscle and viscera were taken to determine Pb and Cd content using Atomic Absorption.The results which were analysed using F. test and ANOVA indicated different but significant concentration of these heavy metals in different species and tissues; however, no significant difference between adult and juvenile fish was found.

A Morphological and Cytological Survey on Freshwater Protozoa of Tehran region (Including their Size, Location and Number of nuclei, type of Locomotion, Silver Line System,) yielded three Paramesium spp and two Vorticella spp for which the classifying characteristics have been determined and a Dichotomous Key for them provided. The Key for Paramecium spp and Vorticella spp is presented in this paper.

Feeding regime of comb-jelly, Mnemiopsis leidyi, in the Caspian sea was investigated by analysing the stomach contents of about a thousand specimens collected from cities of Fereidoun-kenar, Noushahr and Noor during spring, summer and autumn. The study of feed particles in the stomachs of the juvenile and adult specimens from all the sampling stations at all seasons revealed the presence of mainly Calanoida and Acartia. Copepods and fish seeds followed next in volume; vegetal particles constituted the least volume. Over 80% of the stomachs of the sampled specimens was found to be full indicating that comb-jelly is voracious.

Following the report on the observation of an invasive comb jelly Mnemiopsis leidyi from the Caspian Sea in Jan. 1999, studies have been carried out to estimate the density and distribution of the organism at selected stations. Samples were collected from depths of 5, 10, and 20 meters by bottom and midwater trawl nets towed at speed of 20 meters per minute for 5 minutes. Results showed a wide distribution of this comb jelly along the southern part of the Caspian Sea and at all depths observed. The highest density of 2483g was measured in 10m depth of Kheyr-rood station, while the minimum of 99g was measured from Gorgan Bay. Wide and fast distribution of this dangerous organism is threatening the Caspian Sea, particularly its fisheries.