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Pennyroyal (Mentha pulegium L.) from the Lamiaceae family is a medicinal plant which has great antioxidant properties. Environmental stresses such as drought can result in changes in the activity of antioxidant enzymes and the content of some biochemical factors in plants. In this investigation, the effects of drought stress on the activity of supe-roxide dismutase, ascorbate peroxidase, catalase, peroxidase, malondialdehyde and soluble sugars content in pennyroyal shoots and roots were evaluated. To create the water deficit, 24-day seedlings of pennyroyal were placed in 1/2 strength Hoagland solution, containing PEG 6000 (0 and 5% (w/v)) for 24 hours. The results showed that drought stress incr-eased catalase activity and lipid peroxidation and decreased superoxide dismutase and peroxidase activity of the shoots. On the other hand, the activity of catalase and peroxidase increased in the roots. Ascorbate peroxidase activity showed no significant difference in the shoots and the roots. Moreover, drought stress significantly increased the amount of so-luble sugars of glucose, galactose, xylose and rhamnosus in the shoots. Therefore, the increased activity in antioxidant enzymes as well as the amount of soluble sugars under drought stress might be a sign of tolerance of M. pulegium under low levels of drought.

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During a period from spring 2008 till fall 2010, Iranian Jerboa population abundance was estimated using distance (linear transect) and capture-recapture methods in the Mirabad plains near Shahreza city in Isfahan Province. In the study period, during the active time of the species except reproduction time, we tried to live-trap, mark, release and recapture individuals based on Schnabel method on different sampling occasions. Simultaneously, we also traversed line transects using motorcycle and spot-light by two observers in different habitat types. We tried to get uniform trapping nights in different lunar nights and different habitat types. The population abundance, using Schnabel and distance methods was estimated to be 226 and 402 individuals, respectively. With regard to the obtained results and species behavior, it seems that distance method yields more precise confidence limits of the estimation compared with capture-recapture method. However, capture-recapture method yields more precise estimates for closed populations because of its more limiting assumptions, but the confidence reliability of abundance estimation of a species depends on the species and its habitat selection behavior completely.                               
                            

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Overgrazing affects plant communities, and is a significant disturbance factor in arid and semi-arid regions. The immediate changes of plant communities after overgrazing in the disturbed arid ecosystems of Iran have been poorly studied. We recorded data from 100 random samples before and after overgrazing in the Golbahar plain located in the northeastern Iran to determine the changes in the plant physiognomic, species composition, and diversity after overgrazing. We compared life-forms spectra, change in the RIVI of the recorded plant species, species composition, and species diversity before and after the grazing. Our results showed that therophytes were the dominant life-form in the area, and decreased after overgrazing. The community composition of the area remained unchanged after overgrazing. Species diversity at the level of rare and frequent species reduced after overgrazing. Our findings implied that overgrazing could not immediately affect the community structure of degraded arid areas. However, it causes changes that might reduce ecosystem services in them. It is not possible to completely exclude grazers in such areas, fencing or reducing the number of the livestock entries should be applied to restore the vegetation in the area.
 
 

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Barnacles are bottom-dwelling crustaceans that live on a variety of substrates, including rocks, mollusk shells, corals, sponges, mangrove roots and leaves, and the body surface of turtles and whales. The present study deals with the species Microeuraphia permitini on the shores of Bandar Abbas in two stations of mangrove forest and rocky beach in a period of two months, and has investigated the morphometrics of the specimens, while considering the effect of the lunar cycle on reproduction, temperature and wind speed of the environment. Five longitudinal parameters (height, basal length and width, opercular length and width) were recorded. The results showed that 90% and 70% of the samples of both stations had eggs in the second day (new moon) and eighth days of lunar months, respectively, and in the twelfth day of the lunar month (full moon) all samples contained eggs. The results showed that there is a significant difference between the height and base length of the barnacle, but the difference between the opercular length, opercular width and base width is not significant. In addition, in both of mangrove and rocky stations, there was the highest correlation coefficient between opercular length and width (r=0.84 and r=0.78, respectively). The lowest correlation coefficient in mangrove station was between base length and opercular width (r=0.5) and in rocky station between height and base width (r=0.2). The wind pattern was variable during this period and the approximate decrease of the north wind was seen during the sampling period. Air temperature changes were seen between minimum 30 °C and maximum 39 °C. In addition to the tidal cycle, wind and temperature can affect the spawning of the species as an environmental stress factor.