فصلنامه گیاه و زیست بوم
پیاپی 43 (تابستان 1394)

The present study explored the flora of the watershed in Ab-barik area of Rigan city in Bam, which is located between 58-23 E to 58-43 E and 28-24 N to 28-34 N. The area of the watershed is 364.64 sq km (i.e., 364 hectares) and the altitude from the sea level is 700 1500 meters. The average annual rainfall is 100 mm. With regard to plant geography, this region is located within Irano-Turanian vegetation region. The rare species were identified and their geographical distribution and biological forms were studied. Generally speaking, 134 families, 107 genera, and 49 plant species were identified and collected, of which 15.6 percent belonged to Irano-Turanian region. The results indicated that 77% of the vegetation properties of the region was Irano-Turanian, 15% was Irano-Turanian and desert-sandy, 4% was desert-sandy, 3% was Irano-Turanian and Mediterranean, and the remaining 1% was of other properties. The high percentage of Irano-Turanian properties may be attributed to the distance of the region from the other vegetation areas. With respect to the number of species, Asteraceae with 20, Papilionaceae with 15, Boraginaceae with 10, and Lamiaceae with 7 species were the most common ones analyzed. The life forms of the studied plants were categorized as: Therophytes (31%), Hemicryptophytes (26%), Chamaephytes 21%), Phanerophytes (20%), and Geophytes (3%). The biological form of the plants is indicative of desert areas in which Therophytes are the most common form. The frequency of the Therophyte species relates to the elevation of the region and the severe and apparent damage caused by overgrazing and deforestation.

Kelussiaodoratissima (wild celery) is a plant with medicinal and endemic values in Iran. It has been reported to be present only in some of the provinces of Iran such as Isfahan, and it is endangered due to illegal harvesting. The purpose of this study is the analysis of habitat characteristics of this species by means of plant, topographic, and climatic factors such as precipitation, temperature, the number of freezing and snowy days, relative humidity, and the sunny hours in its habitats in Isfahan province for determining the conditions required for its mass cultivation. First, the distribution boundary of the species was specified using 1:50000 topographic maps and field activities during 2006-2008. Afterwards, the maps of the habitat and climatic-factors were designed by means of twenty-year-period data from climatic stations inside and nearby to the study area, using Arcgis and Surfer software. The results indicated that wild celery grows in regions with 2000 to 3500 height range, and the slope range of 30% to more than 60%, with the average annual precipitation ranging from 719 to 943 mm, the average annual temperature varied from 9 to 12 C, the freezing and snowy days ranging from 104 to 134 and 27 to 40, and the relative moisture and sunny hours varied from 44% to 48% and 2935 to 2981 hours, respectively. Kelussiaodoratissima habitat was classified as a cold humid climate, using Embereget method, and as a very humid climate on the basis of De Martonne method. On the whole, the results of this study may be useful for site selection of appropriate fields for growing Kellusia odoratissima.

The pure, uneven, and irregular mass of mangrove in Qeshm habitat is the widest mangrove community in Iran. Using ground visits and satellite images, the forest areas were divided into three areas with respect to the density of the canopy i.e., dense, mediumdensity, and low-density. For this purpose, six transects were selected in these three regions. At the length of each, the 1R, circle-shaped plots at a distance of 100m2 were selected and finally the growth parameters, the number of trees per hectare, canopy percentage, the height of the tree, the density and height of aerial roots, regeneration, and canopy diameter were measured in the 60 sample plots. For so doing, first, the measured growth parameters were normalized and the statistical relations between them were explored by means of the ANOVA test. For comparing the means, Tukey-HSD test was applied. The correlation between the growth parameters was measured by the Pearson test. The results indicated that there was a significant difference between the growth parameters, density per hectare, coverage percentage, density and height of the aerial roots, regeneration, and canopy diameter at 99 % confidence interval. The results also revealed a positive correlation at 99% confidence interval between the density per hectare and the coverage percentage, the density of the aerial roots, regeneration, and average crown diameter. A similar positive correlation was also found between the crown coverage percentage and the height aerial roots, regeneration, and the average crown diameter. There was a positive correlation at 95% confident interval between the height of the aerial roots and regeneration on the one hand, and the regeneration and the average crown diameter on the other. It can be generally concluded that in the dense forest areas, the spread of estuaries, sediment disposition, the wave shock, the tidal characteristics, water and soil salinity, and pH are in a way that provide the best area for the establishment of mangrove forest communities.

As a one of the most valuable commodities of the world agriculture, saffron has a special importance in Iran’s non-petroleum exports. As a result, identifying and locating the suitable sites for cultivating saffron is considered as one of the most significant factors in its sustained production. The purpose of this experiment was using AHP (analytic hierarchical process) for zoning the suitable regions to cultivate saffron in Shurrud basin areas in Neyshabour city by means of the potentials of the geographical information system within a comprehensive spatial analysis framework. In this study, three main criteria, eight subcriteria, and twenty three indices were used to select saffron cultivation zones. After obtaining the overlay weight, the composition of the layers under analysis was accomplished through simple weight mixing procedure and finally the zonation map was produced in three suitable, moderate, and unsuitable levels. The results indicated that about 1000 hectares of basin lands were suitable for the cultivation of saffron, 2000 hectares had moderate suitability, and 5000 hectares were unsuitable.

In this study, an inventory with fixed area plots has been used. A total of 76 circular plots in the closed and grazed area were harvested and the species within each plot, the large and small crown diameters, the distance of the plot center to the nearest tree, the distance of the nearest tree to the first nearest neighbor, and the distance of the first nearest neighbor to the second nearest neighbor distance were also measured and recorded. Using the obtaineddata, the indices of dispersion patterns (Johnson zimmer, Eberhardt, Hopkins, Hines, Pielou, and C index) were calculated. Furthermore, the number of plants in each plot was measured and, using this information, the quadrate indices (green, morisita, dispersion index, and lioyd Index of Patchiness) were calculated. The results indicated that Johnson zimmer, Hines and Eberhardt dispersion indicators estimated the distribution pattern of the trees in the closed and grazed areas as bulked. The Hopkins index indicated the distribution of (Pistacia atlantica) trees in these two areas as random, while the C index revealed a uniform distribution pattern of trees in both areas. However, the dispersion pattern of the trees in the closed and grazed areas were respectively bulk and uniform according to the Pielou index. The quadrate indicators (Mvrysta, Dispersion index, and Lioyd Index of Patchiness) estimated the distribution pattern in both regions as bulk except for the Green index which indicated a random pattern for both areas. The results confirm the bulk distribution pattern for pistachia trees in the closed and grazed regions.

Panicum turgidum Boiss. is one of the important plant species on coastal rangelands of Hormozgan province that plays a significant role in soil conservation and forage production for livestock. In order to investigate some of the ecological characteristics of this species, the present study was carried out in 2011 in Hormozgan province. First, the distribution map of the species was provided and then the investigations were carried out in three regions: Jask, Sirik, and Divan. The height domain of this plant ranged from 0 Alt. in Qeshm Island to 100 m Alt. in Charak on sandy soil texture and fixed soil sandy hills. The geological units of the distribution area were transverse dunes and sand plains. Drawing on the land potential maps, the land use units were X.2, 8.2, 8.1, and 3.5. The highest and lowest canopy covers were 11.8 % (Jask site) and 6.05 % (Sirik site), respectively. The highest and lowest coverage percentages were 11.8% (Jask site) and 6.05% (Sirik site). The highest and lowest species density also belonged to Jask and Sirik sites, respectively. The soil electrical conductivity, pH, CaO content, and sand percent were 0.43-5.93, 7.69-8.75, 26.43 60.69, and 67.68-91.33. The result showed that the pH, electrical conductivity, and Carbon percent did not significantly differ across the sites. Generally speaking, the climatology parameter was the major species distribution factor in the province and drawing on the climatological parameters almost similar to the habitats of this species, the changes in the vegetative factors can be attributed to the soil parameters.

To explore the impact of drought stress on the amount of oxidant compounds and antioxidant capacity of alfalfa, a factorial experiment in completely randomized block design with three replications was carried out using Yazdi and Hamedani cultivars in four drought levels including 100 (as control), 75, 50 and 25% field capacities. Drought stress effects on superoxide (O2 •–), peroxide (H2O2), α-tochopherol, ascorbic acid contents, and antioxidant power were investigated. The results indicated that the drought stress increased the amount of peroxide content in both cultivars, while the increase in Yazdi cultivar was more than the Hamedani one. The amount of superoxide content increased in both cultivars with Hamedani cultivar showing more increase at P≤0.05. The results of drought effects on antioxidant compounds indicated that α-tochopherol content significantly increased in Yazdi cultivar at 75% FC, but reduced in all drought levels in the Hamedani one. In both cultivars, drought stress caused an increase in ascorbic acid content and antioxidant capacity. In Yazdi cultivar, the ascorbic content and antioxidant capacity significantly increased only at 50% FC, but in Hamedani cultivar, these factors were significantly higher at P≤0.05 in all drought stress levels compared with control. It can be concluded that alfalfa increases its oxidant capacity in response to drought stress and against the oxidant ions resulting from such a stress. Since the antioxidant capacity was increased more in Hamedani cultivar compared to the Yazdi one, Hamedani cultivar can be considered as a more resistant cultivar. This, however, requires further research.

In an attempt to compare the accumulation of Cd in the root and leaves of Thuja orientalis and Olea europaea and to investigate the effect of different concentrations of Cd (0 control, 200, 500, and 1000) on Proline and soluble sugar accumulation in these plants, an experiment was carried out in a completely randomized block design with three replications. With an increase in the consternation of Cd, the amount of Proline increased in Thuja orientalis. This amount was 20.5 in the control which increased up to 41.6 as a result of 1000 Cd treatment. An increase in Cd did not have a significant effect on Proline accumulation in Olea europaea. The results of this experiment indicated that the soluble sugar increased significantly only in the concentration of 200 ppm in both plants, but in higher concentrations, there was no significant difference in its amount. The accumulation of Cd in the leaves and root of Olea europaea increased in the concentration of 500 but decreased in the concentration of 1000. The highest Cd accumulation in the root of Olea europaea was 428 ppm in the concentration of 500, of which only 9.8 ppm was transferred to the leaves. The results also revealed that the highest Cd accumulation in the root of Thuja orientalis was 607 ppm in the concentration of 1000, of which only 49.6 ppm was transferred to the leaves. Considering the accumulation of a significant amount of Cd in the roots of the plants under study, it can be concluded that they can be used as phytostabilizators.

Over the recent years, the growing city area in Tehran has increased the air pollution in this city and it can be argued that the percentage of this pollution has not been stable but its intensity has increased each year. On the one hand, the essence of building parks in the city and the diversity of species and, on the other hand, the elimination of some of the existing species due to the lack of compatibility have introduced new species to Tehran. The entry of new species without examining their allergenicity effect can cause several problems. For example, ailantus tree is suggested to be planted in Tehran. In the present experiment, it was observed that the skin sensitivity of ailanthus is more than platanus. However, changes in the blood levels of IgE and Eosinophils in guinea pigs is similar to platanus. Thereby, planting ailantus in Tehran is not recommended.