Caspian Journal of Environmental Sciences
Volume:6 Issue: 2, Spring 2008

Freshwater fish Cirrhinus mrigala were exposed to lethal concentration (5 mg/L) for 1,2,3,4 days and sublethal concentration (1 mg/L) for 1,7,14,21 days of cypermethrin to examine the enzymes activity, in functionally three different tissues namely, gill, liver and muscle. Activities of Aspartate aminotransferase (AAT), Alanine aminotransferase (AlAT) and Glutamate dehydrogenase (GDH) increased in all the tissues with increase in exposure time. But in sublethal concentration at 14 and 21 day, a decreasing trend was observed in all the tissues exposed to cypermethrin. At most instances, fish in lethal medium were affected more compared to sublethal concentration.

Human activities have continuously increased the level of heavy metal ions circulating in the environment. It is important to understand the tolerance of plant species to high concentrations of heavy metals. Very little is known on the response of Eucalyptus species to Zn and Cu toxic concentrations Eucalyptus camaldulensis, E. microtheca, and E. occidentalis seeds were grown in silt and irrigated by nutrient solution. Forty two days old seedlings were exposed to ten Zn and Cu treatments for ten months. The tolerance order of the species to toxic concentrations of Cu was Eucalyptus camaldulensis> E. occidentalis> E. microtheca and the tolerance order of the species to toxic concentrations of Zn was E. occidentalis> E. microtheca> E. camaldulensis. Tissue concentration increased as Zn and Cu concentration increased for the species. Root tissue concentrations regards to Zn and Cu concentrations were higher than shoot tissue concentration at all solution. These results provided the first quantified metals in Eucalyptus species and the second explored relationships between concentrations of metals in nutrient solution and plant organs.

The optimum road spacing has been studied by many researches. It is an important step of forest road network planning. The goals of this study are determining the optimum road spacing in Kheiroudkenar forest of Nowshahr in Northern Iran and study of effect of kind of skidder on skidding cost and road spacing. Continues time study method was used to determine the production rate of TAF and Timberjack 450 C skidders in two districts of Kheiroudkenar forest. The production models were developed using stepwise regression method with 46 working cycles for TAF and 44 for Timberjack. The total road construction and skidding cost were calculated for different road spacing for both skidders in one-way and two-way skidding. Based on minimizing the sum of the road and skidding costs, the optimum road spacing was estimated as 1714 m and road density of 5.8 m/ha for two-way skidding by Timberjack and estimated optimum road spacing of TAF was 1600 m and road density of 6.25 m/ha. For one-way skidding, the optimum road spacing of Timberjack was 1143 m and road density of 8.8 m/ha, for skidding by TAF, the optimum spacing was estimated as 1114 m and road density of 8.97 m/ha. The existing road density of Timberjack and TAF skidding sites was 28.16 and 17.11 m/ha respectively which are higher than optimum density. The study of variants method is applied to find the optimal network for existing network in Namkhaneh district

The leaf nitrogen content is generally accepted as an indicator of food quality and as a factor affecting host selection by phytophagous insects. The alate pea aphids (Acyrthosiphon pisum Harris, Aphididae) were given a choice among non-nodulated pea plants (Pisum sativum L.) supplied with one of four nitrate-N levels (0, 3, 15 and 30 mM). When whole plants were exposed to aphids for 7 days, the results indicated that the settling response of alatae, and subsequently the reproduction of alighted aphids, increased as the level of N supply or the concentration of total soluble nitrogen of the leaves increased, with the exception of the highest N supply (30 mM N). However, the density of settled alatae (in terms of number per unit leaf area) increased as the level of N supply decreased, being greatest on N-deficient plants (0 mM N treatment) and lowest density on N-sufficient (15 mM N) and N-excess (30 mM N) plants. In a free-choice experiment, equal-sized leaf discs taken from the different N treatments were exposed to alate adults for 24 h.The settling response of aphids was positively affected by leaf colour (yellowing), with the greatest number settled on yellow leaf discs (N-deficient plants) and fewest settled on green or dark-green discs (N-sufficient and N-excess plants). Relationships between level of N supply, total soluble nitrogen concentration, total chlorophyll concentration, plant growth parameters and aphid abundance (number of alatae per plant) or density (number of alatae per unit leaf area, or per leaf disc) were established. The implications of results for integrated aphid management were discussed

Studies have showed the River Siahroud is the main contributor to the present pollution of Anzali Wetland in Guilan. Therefore, this study was initiated to evaluate the spatial distribution of metals pollution on the River Siahroud sediments in Guilan.Surfacial river sediment samples along this river were taken during five consecutive seasons at eight sampling stations and analyzed for availability of Fe, Mn, Pb, Zn, Cu, Cr, Cd metals. Canonical correlation demonstrated that the total organic carbon (TOC) was of great importance in co-precipitation of Zn while Cu and Pb were mainly related to hydrous iron oxides. Also, in the interest of pollutant finger printing, factor analysis showed that extractable Zn, Cu, Fe, Cd and Mn were attributed to the present agricultural fields while industrial site of Rasht City was the major contributing factor for the extended levels of Cr in the study area. Moreover, Pb level was mainly relevant to urban landuse in Rasht. Cluster analysis demonstrated that there was a rising metal pollution level in the River Siahroud from upstream to downstream suggesting that Anzali Wetland pollution could be highly related to loading of heavy metals by the River Siahroud sediment.

Land use planning is a science that determines the type of land use through studying the ecological character of the land as well as its socio-economic structure. It is possible to plan for the appropriate use of the land and to enhance the present management of the land use by utilizing Geographical Information System (GIS). To this end, our investigators identified and took steps toward developing maps to determine the ecological and socio-economic resources of the Loumir watershed that encompasses an area of 20884.94 hectares. Digital maps were inputted along with explanatory data into an ArcGIS software application. In addition, all digital maps of layers including, elevation, slopes and aspects, soil texture, depth and structure, geology, iso-hyetal, iso-thermal, iso-evaporation, soil erosion, vegetation or canopy percentage, climate and water resources have been integrated- superimposed in the ArcGIS environment based on the Makhdoom analytical and systematic analysis model. Finally, land use planning maps of the Loumir Watershed were developed considering the ecological and socio-economic characteristics of the area. The results of the evaluation of the area indicated land use appropriateness and allocation as follows: 6.07 percent for level 1 of agriculture, 1.1 percent for level 2 of agriculture, 4.34 percent for level 1 of forestry, 53.31 percent for level 2 of forestry, 11.01 percent for level 3 of forestry, 0.42 percent for conservation, 0.13 percent for level 1 of range management, 6.16 percent for level 2 of range management, 14.71 percent for level 3 of range management, 0.34 percent for aquaculture and 2.41 percent for ecotourism.

An investigation was carried out to reveal the changes in the concentration of soluble carbohydrates under tuber dormancy in food yam (Dioscorea esculenta) tubers and in an economically important spice cum medicinal plant turmeric (Curcuma longa) rhizomes under storage. Harvested, fully matured tubers of yam and rhizomes of turmeric were stored in wooden boxes under the conditions of 28 ? 2?C temperature and 65 to 75% relative humidity in dark. The moisture content, dry weight, starch, sugars, organic acids and respiration were studied in the tubers during 1 to 7 weeks after storage individually. This investigation revealed that the moisture content, dry weight and starch levels decreased gradually with a concomitant increase in sugar content under different stages of dormancy.

Pathogenic infection in tasar silkworm, Antheraea mylitta Drury. is common and there is a breed specific response regarding tolerance. Observations reveal the possibility of differential response by haemocytes to microbial infection in different breeds. Hence, the susceptibility of three eco-races of tasar silkworm viz. Daba, Sarihan and Raily to Antheraea mylitta Cytoplasmic Polyhedrosis Virus (AmCPV) infection and difference in total haemocyte counts were tested. The survival of Daba, Sarihan and Raily eco-races was significantly different (p < 0.05) when challenged with the same concentration (1 x 105 polyhedra/ml) of AmCPV. Daba eco-race was more tolerant to the AmCPV infection having higher survival (66.7%) and LC50 values (1000893.1796 polyhedra/ml) of AmCPV followed by Sarihan eco-race (50.7% survival and LC50 value of AmCPV 187203.6168 polyhedra/ml.) and Raily eco-race (25.3% survival and LC50 value of AmCPV 5176.37 polyhedra/ml.). Difference in total haemocyte count i.e. higher in tolerant (Daba) and lower in susceptible (Raily) eco-race may be in response to difference to their susceptibility to AmCPV infection.

This research was conducted in the west forest of Guilan, northern Iran. Data from various harvesting methods for 20 years were collected. Results showed that, productivity rate of round wood, pulp wood and fuel wood has had an upward trend, while rate of traditional products (lumber, sawn wood, charcoal, etc.) has had a downward trend. Production cost has been investigated in this research. The results showed that, the main cost is the opportunity cost. Due to the disability of competition between the domestic wood price with the imported wood price, domestic wood industries will face serious investment difficulty in the future.