ECOPERSIA
Year:2016 | Volume:4 | Issue:1 |Papers Count:7

This research aimed to evaluate the effect of planting seasons (autumn and spring) on 10 accessions of two species of Astragalus effusus and Astragalus brachyodontus in the field condition (Homand Absard station, Damavand). After preparing the seedbed, the plant species were planted on two lines in 2 m, where the spacing between the lines of each accession was 0.5 m, and the spacing between the lines of different accessions was 0.75 m. The selected design for this study was a complete randomized block with three replications. Evaluation parameters were: forage production, canopy cover, plant height, seed yield, and number of flowering stems. Data were analyzed using split plot in time as year for each plot, and mean comparisons were made using Duncan’s method. The results showed that planting seasons had a significant effect on most of the measured parameters in different accessions. Autumn planting increased the forage production, height, canopy cover and number of flowering stems. The species A. brachyodontus (Zereshk), A. brachyodontus (Alamut) and A. effusus (Dareh Shohada) had high production and canopy cover in the autumn cultivation. Thus, the mentioned accessions are recommended for the improvement and development of rangelands and abandoned dry land farming with the same weather conditions of Homand Absard station.

The study was conducted to investigate the effect of humic acid on the germination properties of medicinal plants Borago officinalis and Cichorium intybus in a completely randomized design with five replications. Experimental treatment comprised the following dosages 0, 15, and 30 g l-1. The results revealed that effect of humic acid on the germination properties of C. intybus was significant (p<0.01) except for the germination percentage and mean germination time (p<0.01). In addition, humic acid was effective on the morphological properties of C. intybus except for radical and pedicel dry weight. Humic acid was also effective on the germination properties of B. officinalis except for the germination percentage (p<1%); it was only effective on morphological properties viz. radical fresh weight, seedlings’ pedical length and allometric coefficient. The most effect was obtained in the 30 g l-1 humic acid. The control treatment had the least effect on the plant's properties. In conclusion, the results showed that application of 30 g l-1 humic acid was effective in germination of the plant species and stimulated the plants germination.

Wetlands as a situ for the growth of native plants, as a habitat for certain species of fish and aquatic birds, and because of their potential economic, cultural and recreational services, are valuable heritage so their protection and conservation is very essential. Mostly due to the absence of wetlands services’ valuation, lack of special regulations, and lack of guarantee for these properties, resources and services of wetlands are not utilized appropriately, and destructed and evacuated in a free and unrestricted fashion, leading to inefficiency in use. The purpose of this study is the economic valuation of Gavkhony wetland ecosystem attributes, estimation of implicit price for attributes, impact assessment of socio-economic variables such as age, marriage, indigenous, family size and education on willingness to pay (WTP), and analyzing welfare and compensation variation due to variation of hypothetical policy. The approach being used is choice experiment that is a subset of choice modeling procedure and stated preference method. Data were collected from six different choice experiments provided in the questionnaires, which were filled out by 500 randomly selected households in Isfahan and Varzaneh cities in the spring and summer of 2013. Each questionnaire contained 72 hypothetical policies, 36 choice sets, 2442 observations and 7327 rows of data. Nested Logitech models and Hausman-MacFadden test were used in order to estimate the visitors’ WTP for improving attribute levels for Gavkhony wetland. This procedure was used on the basis of multinomial discrete choice analysis of preferences, Lancaster’s theory of value and the theory of random utility function. The Hausman-MacFadden test results showed that cross-elasticity between the first and third options was the same. Thus, these two options were placed in the second nest. The results further showed that the visitors had WTP for preserving forest diversity and vegetation of wetland and its surrounding; preserve of natural habitats and organisms life of wetland (bird, fish and animals); wetland hygiene (preventing industrial and domestic effluent, and water salinity); and increasing the water surface (increasing wetland water inlet). The values estimated for these four aspects correspondingly were 8636, 12584, 11553 and 4740 Rials. Some socio-economic variables such as gender, marriage, age, family expenditure, education and being native had a positive impact on the visitors’ WTP. The surplus welfareresults showed that in 72 hypothetical policies, option 1 had the most positive welfare, and option 5 had the most negative welfare for the users of Govkhony wetland. The surplus welfare results based on WTP estimation provide important tools for policy making.

The effect of salt stress on the pysiological and biochemical responses of the seedlings of eight Eucalyptus species viz. E. kingsmillii, E. tetragona, E. salubris, E. occidentali, E. microtheca, E. camaldulensis, E. globules and E. sargentii was analyzed. Four month-old seedlings grown in greenhouse were watered by five levels of salt solution (0, 50, 100, 150 and 200 mM of NaCl) in five replications with a factorial experimental design. The results indicated that salinity delayed and inhibited the seedlings’ growth after one month, and induced gradual decline in most of the criteria such as leaf area, relative water content and specific leaf area. Moreover, a significant reduction of chlorophyll a, b and total chlorophyll content was observed. Salinity stress raised the content of soluble sugars, proline and glycine betaine. Eucalyptus sargentii as the most tolerant species had the optimum growth up to 200 mM NaCl but E. globulus presented the most sensitive species to salinity stress. At 200 mM NaCl, proline and glycine beatine raised to 10.57 and 27 mg g-1 in the tolerant species (E. sargentii), respectively while proline in the sensitive species (E. globulus) dropped to 0.003 mg g-1. These results suggest that high tolerance of E. sargentii to salinity stress is closely related to lower specific leaf area and enhancement of compatible solutions such as proline, soluble sugar, glycine beatine. This would encourage the possibility of propagating E. sargentii in the southern coastal area of Iran. Furthermore, these results provided further biochemical support for the specific abiotic stress tolerance mechanism of Eucalyptus species.

Ongoing climate change has been a major global challenge since the 1880s. Sequestration of carbon (C) in rangelands ecosystems could provide a net carbon sink to offset increases in atmospheric C in global scale. This research is aimed at estimating the above-ground biomass carbon sequestration potential in Iran. For this purpose, total rangelands area and productivity data were extracted from the annual reports of Agriculture Statistical Pocketbook (2006-2013) of the country. Then productivity data was used to calculate above-ground C storage per province. The maximum and minimum rangeland areas were observed in Sistan and Baluchestan and Mazandaran (Nowshahr) Provinces, respectively. Maximum above-ground biomass C storage was about 1.07 Mg Cha-1y-1 in Fars Province. The minimum amount occurred in Qom province with only 0.023Mg C ha-1 y-1. In summary, mean carbon CO2fixation was about 0.25 Mg C ha-1 y-1in Iran’s rangelands from 2003 to 2013. Considering the total rangeland area (≈ 84.8 million hectare) and productivity of Iran, 11770.011 Gg C y-1 carbon is stored in above-ground biomass annually providing at least 5885 Gg organic C sequestration potential.

This study reports the incidence of histological alterations in morphometric changes in the liver and ovary of Acanthopagrus latus collected from an urban stream impaired by anthropogenic activities and from a clean site (reference). Mercury concentration was determined using a standard cold vapor atomic absorption. The results showed that mercury concentration at the creek waters, and specially sediments along Mahshahr coast, was higher than in the other marine environment, and in Zangi was lower than in the other sites of sampling. Several liver lesions were identified, including enlarged and lateral nuclei, nuclear degeneration and vacuolation, oncotic, apoptic, focal, massive, centrilobular and periportal necrosis, atrophy, lipidosis, hydropic and cloudy swelling, oval cell proliferation, cirrhosis, hemorrhage, macrophage aggregates, bile stagnation, dilation of sinusoid, intracellular edema, and dark granules. Ovary histology revealed some changes in higher concentrations such as increase in the number of pre-vitellogenic oocytes, oocyte atresia, and adhesion in the ovaries of females that were sampled from the sites with high concentration of mercury. In this study, existence of mercury in Mahshahr coast is demonstrated and high incidence of histological alterations in the liver and ovary of A. latus is an evidence of the poor environmental quality of creek waters. Hence, histopathological changes were induced by the mercury adversely affected the proper functioning of these organs in these fish.

Drought is a complex natural phenomenon that can occur in any climate. Hydrologic drought in the river flow of arid and semi-arid areas causes serious shortages, threatens the quality of life, and impacts on the economy. Understanding this feature is then essential for the management of water resources. Hydrologic drought in the sense of deficient river flow is defined as the periods that river flow does not meet the needs of planned programs for system management. In the present study, changes in the monthly discharge of 14 hydrometric stations throughout the Gorganroud watershed over 30-year period (1980-2010) were studied. Then the deficit flow was determined based on threshold level method, and the results were analyzed. It was revealed that periods of severe shortages have happened in the very humid and semi-arid climates and the downstream of the study area, while longer periods (28 months) of low flows have occurred in the arid climate. The trend of severity and persistence in the central stations of the watershed was increasing. Also shortages occurred with greater frequency at the end of the study period, and river flow shortage during the years 1998-99, 2007-2008, 2008-2009 and 2009-2010 has occurred in most of the stations. So in these years, flow deficit has happened in 50, 85.9, 64.3 and 92.8 %of the stations, respectively.