Journal of Rangeland

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A completely randomomized design with four replications was used to evaluate the toxicity effects of various nano Fe₃O₄ concentration (0, 50, 100, 200 and 400 µgml^-1) on germination and the growth of radicle, plumule and seedlings of  Agropyron desertorum and Agropyron elongatum. Results showed that the germination percentage and seedling growth of both species were reduced using high concentration of nano Fe₃O₄. The concentration of 400 µgml^-1 of Fe₃O₄ nano particle reduced the germination percentage of A. desertorum and A. elongatum from 95% and 84% to 70% and 45% respectively. 400 µgml^-1 of Fe₃O₄ nano treatment also reduced the seedling growth of A. desertorum and A. elongatum from 8.08 and 11.62 cm to 6.32 and 7.27 Cm respectively. Results indicated that A. elongatum is more sensitive to nano Fe₃O₄ compared to A. desertorum.
 

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This research was conducted to investigate the characteristics of Vicia variabilis Grossh seed germination in response to different levels of dryness and temperature in two phases of laboratory and greenhouse. The research was done as a factorial based on a completely randomized design with four replications. The treatments consisted of 7 temperature levels, five levels of drought treatment and non-stress treatment (control). In a greenhouse trial, a completely randomized design was applied to four treatments including control (without irrigation), irrigation from planting until May 5, and irrigation from planting until May 20, irrigation from planting until the end of growth period. The results showed in all temperature treatments, the highest percentage of germination was observed in control. By decreasing the water potential from the control to -1Mpa, the percentage of germination decreased. Seed germination at 15 and 20 °C were observed at all the water potential levels. Germination did not occure at 35 °C. The highest rate of germination (12.71 seed/day) was observed at 20 °C, and with decreasing water potential, the rate of germination decreased (0.19 seed/day). Among all the treatments of the water potential and temperature levels, the highest germination rate was in 20 °C for the control treatment (3.81 day) which did not show significant difference with its amount in the first and second levels of the temperature (20°C), as well as at 15 °C (4.71 day). The highest radicle length (30.37 mm), shoot length (31.37 mm) and seed vigor index (0.3288) were observed at 15 °C. Based on the results of pot culture at the beginning of the cultivation, irrigation significantly increased the percentage of germination. This irrigation was sufficient for 50 days for the survival of germinated seeds and plant growth until the end of the vegetative period. The results of this research can be considered in rangeland rehabilitation projects.
 

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The changes in the richness and plan’s tdiversity are of the signs of ecosystems manipulation. The more diverse the ecosystem is, the greater its resistance to degradation. Regarding the importance of this issue, this research was conducted in Arangeh rangelands located at  the southern hills of Alborz. Investigate of the changes in species diversity and functional diversity of vegetation under different biological situation was the goal of the study. Data collected from five sites under different biological circumstances namely, seeding, pit seeding, exclosures, grazing management and natural rangeland. Indices of species diversity including: richness (S), Shannon (H), evenness (E) and Simpson (D) and the functional diversity index (convex hull hyper-volume (CHull), Functional Richness (FRic), Functional Evenness (FEve), Functional divergence (FDive) and index Rao (Rao) were calculated for all sites. FD package and generalized canonical discriminant analysis (gCCA) were used in R 3.1.1to calculate these indices and determine the effect of grazing intensity on diversity indices. In addition, Duncan's test was used to compare the means of grazing intensities. The results of the mean comparison indicated that the natural rangeland has the highest Shannon index and has a significant difference with the exclosure site. There was no significant difference in seeding sites and  natural rangeland in terms of  richness index. For other measures such as cluster analysis there was significant difference at (p< 0.05). The results of analysis of variance for different performance variables indicated that among functional diversity indices, except for the (CHull), functional richness indicators (FRic), functional divergence (FDiv) and evenness (FEve) showed a significant response to biological measures. The results of the mean comparison showed that Rao index had the highest value in the exclosure.

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Background and objectives: Iron and related mineral industries are one of the important pillars in industrial development. Extraction of iron ore and steel production is not possible without land degradation, and in this process, in addition to steel, is a large volume of mineral tailings which if not properly managed, will be able to pollute soil, air, and water, that can pose significant health challenges. The aim of this study is to evaluate the establishment and germination of desert mustard on Gol Gohar iron mine tailings in sake of biological rehabilitation of the tailings.
Methodology: At first, sampling of tailings and soil of desert mustard (Sinapis arvensis L.) habitat from Gol Gohar mine area were taken. In order to compare the particle dimensions, Granulation was done by dry sieving for both substrates and some of their physicochemical properties were investigated. Properties such as bulk density, EC, pH, Organic carbon, Phosphorus, Nitrogen, and Lime for tailings and soil were determined by conventional laboratory methods. Desert mustard seeds before planting in soil and tailing, were tested for germination. After ensuring the vigour and germination of seeds, they were planted in plastic pots with soil and mineral tailings and randomly placed in the growth chamber, irrigated daily with distilled water until the end of the experiment. Germination was recorded daily for 16 days until germination stopped. After this period, the planting medium of the pots was washed with a gentle stream of water and the seedlings of each treatment were weighed separately and their root and shoot lengths were measured. By counting the germinated seedlings, Germination Percentage, Mean Germination Time, Coefficient of Velocity of Germination, Germination Index, Mean Daily Germination Percent, Peak Value for Germination, T50,  Germination Value, Seedling Vigour Index were calculated based on the Common formulas, and at the final step, the mean of all data was tested by means of an independent t-test.
Results: The results of the independent t-test showed that there was no significant difference between pH and EC in the two substrates, but the difference between Carbons, Phosphorus, Nitrogen, Lime; Specific mass, mean particle diameter, and ᵠ index between the two treatments is statistically significant (P < 0.01). The Mean Daily Germination Percent results show that the onset of seed germination was the same in two treatments, but the peak of germination has occurred for the soil substrate of 16.66% on the fourth day and for the tailings substrate of 12.85% on the fifth day so in addition to the peak germination time, Germination Percentage is less in the tailing substrate. Although the Germination Percentage in the soil of the mustard habitat is equal to 64.28% and this is more than the Germination Percentage in tailings substrates, which is 56.19%, but as the Coefficient of Velocity of Germination and Mean Daily Germination Percent, the difference between the means is not statistically significant. This is while Mean Germination Time, Seedling Vigour Index, and T50 showed a significant difference (P < 0.05), in other hands the difference between the mean of the other parameters included Germination Value, Peak Value for Germination, Germination Index, Seedling weight, and Root to stem ratio, also is significant (P < 0.01).
Conclusion: The results showed that the lack of N, C, and P in mineral tailings have a negative and inhibitory effect on the growth of mustard seedlings. Strengthening the tailings with nutrients is a vital treatment for the establishment and growth of plant seedlings, meanwhile adding Lime to tailings is essential to reduce the negative effects of heavy metals on plants and soil. On the other hand, it should be borne in mind that ecological remediation of mineral tailings will not be available in the short term without the use of unpolluted and biologically active soil, so topsoil and overburden can be used as an important and reliable source of seeds for regenerate vegetation.
 

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Background and objectives: Problems of germination and establishment of plants in drought and dehydration conditions is one of the common problems in arid and semi-arid regions which affects the growth and production of plant communities. Improvement of seed germination and establishment of plants under drought stress is one of the most important issues in success of rehabilitation projects of natural areas. Range species of Sanguisorba minor and Agropyron intermedium are mainly distributed in semi-arid ad semi-humid climates. In this research, the possibility of germination and establishment of these species were investigated under different priming treatments in an arid region.
Methodology: The effects of different priming method such as distilled water, polyethylene glycol (0.1 Mega-Pascal), potassium nitrate (0.2%) and silver nanoparticles (at three levels of 30, 60 and 90 mg/l) were investigated. Treatments were applied for improvement of seed germination characteristic and plant establishment under different irrigation regimes at field capacity and drought stress and under field natural condition. The experiment was performed as a factorial in a randomized complete block design with 4 replications and in total 56 plots was considered for each species. The dimensions of each construction plot were equal to 1.5 square meters and in each plot, three planting rows with a distance of 30 cm and a length of one meter were considered and 45 seeds were planted in each experimental plot. The measured traits were included the percentage and velocity of appearance of seedlings from the soil, establishment and survival, length and weight of root and stem, vigority, prolin, carotenoid, soluble sugar, total chlorophyll, catalase and superoxide dismutase enzymes. After sampling the studied traits in the field and obtaining the results obtained in the laboratory, analysis of variance and analysis of data in SPSS software and comparison of mean data with Duncan's multiple range tests at 5% level for the studied traits were performed in both species.
Results: Statistical analysis of the results showed that the application of priming has been more effective on soil appearance percentage, appearance rate and establishment and survival of seedlings, but it has also affected other studied traits. Application of silver nanoparticles had positive/negative effects on the vegetative characteristics of seeds and seedlings grown from the seeds of the studied plants. Application of polyethylene glycol and potassium nitrate in A. intermedium and application of polyethylene glycol and silver nanoparticles with concentration of 30 mg/l in S. minor showed the highest positive effects on plant resistance under drought stress. Application of silver nanoparticle at concentrations of 60 and 90 mg/L showed negative effects on the vegetative and physiological characteristics of two studied species as well. Increase of 25% and 13% in biomass production under the treatment of silver nanoparticles with a concentration of 30 mg/l and decrease of 12% and 3% in the biomass under the treatment of silver nanoparticles at a concentration of 90 mg/l, respectively were observed for A. intermedium and S. minor species.
Conclusion: Increasing the rate of water absorption and metabolism in primed seeds leads to more germination, reduces the natural and inherent physiological non-uniformity of buds and increases drought tolerance and plant yield. The positive effect of silver nanoparticles is mainly due to facilitating the penetration of water and nutrients into plant seeds and improving germination properties. Using the results of this research can increase the success rate in the cultivation and establishment of S. minor and A. intermedium range species in arid and semi-arid rangelands and increase the efficiency of biological projects for rangelands improvement and rehabilitation.