Year:2003 | Volume:16 | Issue:4 (59 IN NATURAL RESOURCES) |Papers Count:18

The genus of Thymus presents 14 species in Iran, which Some of them are endemic. In this project some of the endemic and non-endemic thymus species named "Thymus carnosus Boiss, T. kotschyanus Boiss. And Hohen, T. persicus (Ronniger ex Rech. F) jalas, T. Pubescens Boiss. Et Kotschy ex Celak, T. serpyllum L. "were collected from different regions at before flowering and full flowering stage. The air-dried aerial parts of these species were distilled for obtaining their essential oils. The oil yields percents are as follow respectively: At before flowering (0.66%, 0.28%, 0.26%, 0.55% and 0.57%) and at full flowering stage (0.86%, 2.1%, 0.43%, 1.45% and 0.90%). Totally the oil yields were lower for these thymus species before flowering. the highest oil yields were obtained from T. kotschyanus and T. pubescens. Analysis and identification of chemical composition of the oils were performed by GC and GC/MS. Thirty-seven components (representing 93.1% - 98/3% of the oils) at before flowering stage and thirty – nine component (representing 88.2%-99.3% of the oils) at full flowering stage were identified.

For estimation of statistical distributions function parameters different methods existed that the most prevailing and the oldest is central moment methods. The use of L - moment has been adopted now only for a years and its application is in primary stages in our country. In this research has done comparison between ordinary moment and new rations of L - moment until clear application of this method in order to estimation of maximum, mean and minimum discharges in north area of country.According to results of this research for annual maximum discharge in LN2 and LN3 distribution, moment method and in P3 and LP3 distribution linear moment method have been suitable distinguish and in Gumbel distribution, moment method and linear moment method equal have been suitable distinguish. For annual peak discharge in LN2and LN3and P3 distribution, moment method, in LP3 and Gumbel distribution linear moment method have been suitable distinguish in all stations. In the case of mean and minimum discharges in all distribution and stations, linear moment method have been suitable distinguish.

Genus of salsola has about 40 species in Iran. It is the biggest genus of chenopodiacea. In order to clarify ecological situation of salsola in Semnan province, this study has begun since 1993 and continued for 2 years. At the begining sal sola species of the province were collected and identified. in this study was identified 15 species in Semnan province, then map of salsola distribution was drowed based on primery information of Semnan province (Scale 1:250000). And then drowed map was matched with maps of isotermal, isorain, isoevaporation, iso climate, available iso water EC, geology and pedology. The results showed that: 1: The most density of salsola types occures in condition of dry, cold, desertic climate (A12M2). ECw 4000-6000 pm, Mean annual rainfall 100-200 mm, mean temperature 12-17.5 C and isoevaporation level between 2000-2600 mm, in this regions water table was 30-60 m. 2: Abundance of salsola types have no corelation with kind of geological sediments, but the most types of salsola are in alluvium deposit areas which have low slope. This deposites drived from weathering process and transported by flood to low lands. Therefore distribution of salsola was effected by upland altitudes. C: The higest distribution of salsola types in altitudes 1100-1600m from sea level, in slop of lower than 10 percent. In addition direction of slope did not effect in salsola accurencey. The most favorable soil for salsola growth are light and aridisoil, pH 7.5-8 and EC between 0-2 mm.

Biospheric reserve is an advanced feature of natural hierarchy with the aim of protecting biological diversity. Nine (9) biospheric reserves have been identified in Iran where Harra Biosphere Reserve in Hormozgan Province is one of the Iranian reserves located in the southern coastal regions, taking within itself a tidal region with the surroundings of this reserve 30 individual kinds of Gastropods from 28 genera and 22 families have been identified where one species of Assminiea genus from family Assiminaedae has been identified for the first time in the global scale. This species are as followed: Selia bandorensis, Milrella blanda, Cyclostrema suprenum, Cerithium cerithium, Iravadia quadrasi,. Lucfdinella' densilabrum, Littoraria intermedia, Granulina oodes, Cerithidea singulata. Stocsicia annulata, Stenothyra arabica, psedominolia nedyma, Cyclostrema ocrinium. The most abundance has been observed in the species of Iravadia quadrasi, Stenothyra arabica and Littoraria intermedia.

To day, the progressive of technology and access able various software and also to recognize in significant parameters of soil erosion and sediment yield is provided in possibility of using different mathematical models. The models, demonstrate to create of hydrologicalevents through mathematical relationships between catchment's parameters. Whereas, the results of using some of models has been satisfied for this purpose. Therefore, using of these models is increased in the most watersheds through more than 40 models. Other side, as the mountainous catchments is very complicated, so simulation models are suitable for estimation of erosion and sediment yield. One of the reliable models for above purpose, is known SWAT model. Where is applied in Amameh catchments. SWAT model has been modified. At present study, the SWAT model has calibrated by monthly and annually observed data, which is recorded in Amameh stations with monthly and daily estimated data, which are obtained by model. In this study catchment's parameters are used as physical parameters for SWAT model. After calibration process, the model has been evaluated by some of sensitivity testing models such as, Nash - Sutcliff model and P-bias model. This process is shown which some of physical parameters are sensitive among the another parameters of the SWAT model such as, K (Soil erodibility parameters) and n (Roughness coefficient parameters). In final, the determine coefficient of observed value and estimated value is obtained, R2=0.74. This result can be obtained for unpaged catchments at same hydrological condition.

Ecological model of forest land use in Iran which is designed for evolution of ecological Capability of lands, Is not appropriate whit ecological characteristics and kind of utilization in "Zagross forests". This paper which is based on objective experiences and the results of the study on ecology of the region, offers a suitable model of forest land use in Zagross forest represented in four different classes, and then the outcome of this study, as a landuse planning. Is used successfully in Darrehshahr watershed. A study on map of forest land use classes, showed that none in the region correspond whit the characteristics of class (1). Areas belong to the second, Third and fourth classes are respectively 463, 1072 and 760 ha. This model has in Iran. And in specializing of the ecological factors of management of Zagross forest. It suitable mentioned that, in this model to determine the preference of landuse. We used the moderated and quantitative-comparative method in Iran.

In this study, the species of the genus Lolium was examined to design map of distribution. The distribution of any species was obtained based on the data of Floras, herbaria and collected specimens. In order to study morphological variation, Seeds of six species of the genus which taken from gene banks and collected around the country, sown in the field. Plants were scored for 24 characters. Cluster analysis and Factor analysis were used to determine relationships between the species. The results were discussed on the basis of the dendrogram of population distributions and factor loadings.  

Medicinal plants have different quality in several natural and agroecosystems. In this experiment which carried out in Karaj research station and natural habitats between 1998-1999, fluctuation of hypericin of Hypericum perforatum was examined. In a spilt plot design under CRBD with 3 replications, chemical fertilizer, organic manure and combination of them were allocated in subplot and plant density was alocated in main plot with.4,5.7 and 10 plant m-2, Hypericum perforatum of some natural ecosystems consist of Gorgan. Nowshahr, Siahkal and Khalkhal were harvested simultaneously. After drying the tops, hypericin was extracted and measured by Soxhlet and Spectrophotometer respectively. The result showed that maximum hypericin produced under combination of chemical fertilizer and manure with 2142 PPM in the second year. Among the natural habitats and field treatments, Gorgan and Siahkal produce maximum hypericin in the high rainy year (1998) with 2730 and 2584 PPM respectively. Comparison between natural and agroecosystems showed a different result in the low and high precipitation, however hypericin content in natural habitats was not less than field treatments. It seems due to reaching to the hypericin production potential in the field, should be duplicate the natural ecosystem characteristics.

A series of experiments was performed in a laboratory flume to determine the effect of change in hydraulic parameters (namely slope and discharge) on the development of meandering patterns. For the purpose, of modeling, an alluvial reach of Ghezel Ozan (a meandering river in central north of Iran) was selected and using reasonable values of geometric, hydraulic and bed material properties of this river, a physical model with horizontal scale of 1:400 and vertical scale of 1:40 was constructed. After performing several laboratory tests, it was found that discharge and slope were close:" related to the displacement of the laboratory meander. Also based on regression analysis of experimental results a number of analytical relationships were obtained for determining the longitudinal and lateral displacement of meandering patterns. The proposed relationship is based on the Non-Dimensional United Stream Power.

In order to determine the relationship between the biodiversity indices woody species and growing stock per hectare in natural beech (Fagus orientalis Lipsky) Forests in Asalem, Twenty sites specially at middle elevations were studied including 3 plots per each site. The dimension of each plot was 50x100 meter. The method of surveying was selective sampling. Results indicated there are positive linear regression between the biodiversity indices and growing stock per hectare. The best equation were obtained from the relationship between shannon - wiener function and growing stock per hectare (r= 0.09).

Besides climate variation, human being interference in natural hydrologic cycle, such as vegetation cover deterioration and expansion of impervious areas, has increased the flood hazard in most regions of the country. In this respect, industrial, agricultural, and residential land uses in many cities and villages are under flood risk. Study of flood active areas within a watershed is therefore essential in flood control design aimed at reducing flood damages. However, little work has been accomplished in this important subject. This paper introduces a new approach entitled Single successive Sub watershed Elimination (SSSE), to survey the flood active area using a hydrologic model, such as HEC-HMS. The study area, Damavand watershed, was broken into seven sub watersheds whose physical characteristics were determined using a geographic information system (GIS). Then, the flood hydro graphs corresponding to different design rainfalls were simulated by HMS. By eliminating a single sub watershed in every run, the peak discharge at the watershed outlet was computed by the model. Thus, the discharge contribution of each sub watershed in flood peak production at the outlet could be determined. The sub watershed with highest impact on the flood peak was introduced as the most flood active area and other sub watersheds were ranked as well. In Damavand, sub watershed unit 3 and 2 was respectively the most and the least effective flood producing areas. Since the areas of the sub watershed units varied with sub watershed 3 being the largest in area, the impact of each unit on discharge quantity was divided by the area of unit. This caused the ranking of the units to change. The proposed method in this paper can be effectively implemented in flood control studies to prioritize the flood active areas.

One of the most important natural dyes is "Madder", used for dyeing of wool aF1dsilk yarns as persian carpet piles. The color of madder can be altered by changes in growing conditions, mordant and pH. Madder is classified in polychromic dyes group, due to its sensitivity to pH. In this research five different mordants with four different acids were chosen to dye the Iranian silk yarns and then the color measurement test with CIE (L*a*b*) system carried out. The results were shown that the mordant is identical factor in the lightness of samples and dyeing of mordanted samples with madder just decreased the lightness without changing its sequence. The results were also shown that using tartaric acid in dyebath could help to obtain higher dye absorption on silk.

The method of plant tissue culture in photoautotrophic conditions has several advantages. Increasing survival rate of transferring in vitro plants to soil and decreasing of probability of fungal and bacterial contaminations are examples. However, steady injection of CO2 to the system is a major limitation, the use of containers surrounding by accumulated CO2 in growth chamber instead of CO2 enrichment removes the limitation. Actively growing shoot tips of micro propagated River Red Gum (Eucalyptus cammaldulensis) were used as explants, and sugar-and hormone - free MS medium at three levels (quarter, half and full) and Enshi medium, were used as media treatments in this study. Four types of supporting material were used: 2.0 gl-1 Gelrite, Foam material, 8.Og Vermiculite per culture vessel and 2.0 gl-1 Gelrite plus 6.0 9 vermiculite. All cultures were maintained for 26 days in the two growth chambers, using indirect CO2-enriched (3000±100ppm) (photoautotrophic) and CO2-nonenriched (semi photoautotrophic). The comparison between two conditions showed that, photoautotrophic condition was significantly superior in fresh and dry weight of aerial parts and left area. Stem length was significantly superior in semi photoautotrophic condition when using appropriate supporting materials. The result showed that CO2 –enriched system was a key factor in increasing quality and quantity of in vitro plantlet production. As an alternative accumulated CO2 in surrounding of containers in growth chamber could be used and the way for improvement of conventional micro propagation, when providing gaseous exchange system is not available.

Gum tragacanth is one of the most important herb gum, which exudation from stem of Astragalus. This gum from economic point is used in medicinal, texture and food industry. Chemical structures are mixture of complex polysaccharides with inorganic elements like calcium, potassium, magnesium and etc. In this research gum of Astragalus gossypinus and verus are collected from Bakhtiyary, Kermanshah, Hamedan provinces, and analyzed by colorimetric method, flamephotometery, and complexometery methods for inorganic elements. In this gum tragacanth observed phosphour is smallest percentages and calcium is highest percentages of others inorganic elements.

Use of satelite images is known as a new technique to study changes in vegtation cover. On the other hand, rainfall plays a key role on the condition of vegetation cover. This article investigates the changes in vegetation and its relation to rainfall days and monthly time intervals over the (1995-1997) period. The region of study is part of Kol river basin located in an area surrounded by Hormozgan. Kerman and Fars provinces using geo-statistical methods. Rainfall maps were generated based on the raingauges in the data collected by area. Maps of daily Normalized Difference Vegetation Index (NDVI) were transformed days images using into day composite technique. Bymaximum preparing a layer representing terrain-mapping units (TMU) the correlation between vegetation cover and rainfall was investigated in different land units. The results demonstrate varying degree of correlation. Specifically the correlation in alluvial and flood plains was strongest. Meanwhile The correlation in monthly time days interval was better compared to interval. The multi-variable regression was also determined as the most suited correlation relationship. 

The design storm is one of the main elements in flood estimation. Regarding to the existence of temporal variations in heavy storms, distinguishing of the rainfall temporal pattern is very important. Rainfall temporal pattern is applied in watershed hydrological modeling and it is necessary as a main input in rainfall-runoff models to gain more accurate results. In this study rainfall temporal patterns in synoptic stations in north of Iran were investigated with mean and probability methods by analysis of real data and derivation of cumulative curves. Assessing the storm temporal patterns by using the mean method in the study area shows that in short duration, the maximum percentage of rainfall amount occur in one-second center of storm duration and as the duration of storm increases the intensity and special variability of storm decrease. By using the probability method, it is shown that most of the rainfall events will occur in the third and second quarter, respectively. In this study, daily rainfall temporal patterns in north of Iran and SCS type were compared and the results show that there is not any similarity between them.