Improving seed germination rate accelerates early seedling establishment, in turn, enhances plant growth and forage production in rangelands and pastures. Rapid and simultaneous germination of seeds leads to successful plant establishment. The ingoing research aims to deals with effect of SiO2 nanoparticles at concentrations of 0, 5, 20, 40, 60 and 80 mg/l on seed germination rate in Astragalus squarrosus. The experiment was conducted for 15 days under constant temperature of 20 °C, 16 h of light and 8 hours dark. The treatments were arranged as factorial based on a completely randomized design with four replicates in Department of Natural Resources at the Ferdowsi University of Mashhad, Iran. The results of experiment showed that the germination percentage of scarified seeds treated with SiO2 nanoparticles with 40ppm concentration was improved compared to control seeds and non-scarified ones treated with nanoparticles. At the same time, some other positive effects of other nanoparticle concentrations on germination rate and percent were obvious so that the effect of different concentrations of nanoparticles on seed germination traits Astragalus squarrosus was found to be significant. The highest and lowest germination percentage was recorded under concentration of 40 ppm and 80 ppm those seeds treated with nanoparticles, respectively. As SiO2 concentration increased, no enhancing positive effect on seed germination attributes of Astragalus squarrosus was found. In this experiment, it was found that seeds scarified and treated with 40 or 60 mg/l of SiO2 nanoparticles showed improved germination in Astragalus squarrosus , so this treatment can be promising for establishment and colonization of this species in natural landscapes. Manuscript profile

Degradation of plant patches is considered as one of the indices for rangeland degrading health condition. Investigating the accuracy of triple indices (infiltration, stability and soil nutrient cycle) presented by LFA method seems necessary to determine its efficiency in semi-arid areas with the least cost. This study aims to investigate the role of vegetative species and growing forms on soil surface characteristics in Dehbar semi-steppe rangelands, Iran in 2014. So, eleven soil surface characteristics in different vegetative types each of 3 replicates were measured using landscape functional analysis (LFA). Then, the measured parameters were classified based on their sustainability, permeability and food chain continuum for each plant species. According to the results obtained from various analytical investigations, the ecological patches consisting of Artemisia aucheri (46.83%) and complex of Artemisia aucheri and Agropyron intermedium (with the amount of 41.7%) were higher than other forms of vegetative growth for soil sustainability. The complex of Acantholimon sp., Artemisia aucheri and Astragalus commixtus had the lowest amount in terms of soil sustainability (38%). The comparison of soil permeability indices for different types of plant covers showed that the percentage of Artemisia aucheri (32.06%) and complex of Artemisia aucheri and Agropyron intermedium (33.5%) had the highest amount while all other patches were equal and had the lowest amount. In terms of food chain, the ecological patches such as Artemisia aucheri (25.63%) and complex of Artemisia aucheri and Agropyron intermedium (27.66%) had the highest amount. The complex of Artemisia aucheri and Astragalus commixtus (16.36%), the complex of Acantholimon sp., Artemisia aucheri and Astragalus commixtus (13.63%) and the complex of Acantholimon sp. and Agropyron intermedium (15.36%) had the lowest values (p≤0.01). Therefore, Artemisia aucheri (shrub) and a complex of Artemisia aucheri and Agropyron intermedium (grass) patches, introduced as ecological indicators for the study area, are suggested for rangelands restoration. Manuscript profile

In order to study the effects of drought stress and mycorrhiza fungi on establishment rate and some growth-morphological traits ofZiziphora clinopodoides, pot experiments were conducted as factorial design based on a completely randomized design at the research greenhouse of agricultural faculty, Ferdowsi University of Mashhad in 2014; pots were combined as four levels of drought stress including 100 (Control), 75, 50 and 25% of Field Capacity (FC) and three levels of mycorrhiza fungi including Glomus intraradices, Glomus versiforme and control. The results showed that drought stress of 25%FC decreased plants weight (0.75, 0.67 and 0.19g/pot), plant height (1.25, 1.18 and 0.7cm), establishment rate (67.50%, 57% and 14.25%) and plants root colonization by mycorrhiza fungi (50%, 35.5% and 0) by the application of G. intraradices, G. versiforme and control, respectively indicating significant effects of both Mycorrhiza species on drought resistance. Result indicated that the establishment rate was decreased significantly to 85%, 64% and 36% using G. intraradices, and G. versiforme and control at 50%FC, respectively. Similarly, the establishment rate was reduced in the inoculated plants with mycorrhiza treatments less than control (67.50%, 57% and 14.25% at 25%FC) so that symbiosis of Mycorrhiza fungi significantly improved Z. clinopodoides establishment rate under drought stress against the control. The effect of G. intraradices and G. versiforme on plants establishment rate (93% against 78.50% at 75%FC), plants height (5.93cm against 5.30cm at 75%FC) and dry weights (1.07g against 0.95g at 50%FC) was higher through drought stress. The Glomus intraradices reacted better to mild drought than G. versiforme and increased the establishment and morphological traits of plant. According to results, G. intraradices could be introduced as a biological fertilizer and a technique for retrofitting and increasing tolerance of Z. clinopodoides against drought stress. Manuscript profile