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Background and Objectives: The impact of grazing on the carbon cycle in mountain rangelands depends on various factors, including management practices and environmental conditions. However, the effects of grazing on carbon stocks remain uncertain due to challenges in tracking small changes in rangeland carbon stocks, lack of baseline information, and limited long-term grazing management data. This study aims to investigate the relationships between plant and soil parameters and organic carbon storage in a 10-year-old exclosure in the mountain rangelands of Asadabad, Hamadan. Methodology: Two study sites, one under grazing and the other under a 10-year-old exclosure, were selected in a manner that minimized the gradient effect of ecological and biological factors. Vegetation and topsoil samples were collected along two 100-meter transects at 20-meter intervals, resulting in a total of 10 plots in each area. Vegetation parameters, including percentage cover, diversity (Simpson index), evenness (Shannon-Wiener index), and richness (Margaluf index), were calculated using Past 4.03 software. Soil organic carbon, phosphorus, potassium, and nitrogen were measured. Statistical analysis was performed using SAS V.4.1 software, and the distribution of variables was analyzed using principal component analysis (PCA) in Canoco 5 software. Results: The findings revealed higher vegetation cover and plant diversity (richness and evenness) in the exclosure area. The vegetation cover percentage and species count in the grazing area were 35.1% and 127, respectively, while in the exclosure area, they were 67.6% and 139. The carbon stocks in vegetation and soil were significantly higher in the exclosure area, with values of 83.13 and 74.35 ton/ha in the soil surface, and 0.00219 and 0.00273 ton/ha, respectively (p < 0.05). The exclosure area exhibited a significant increase in Simpson diversity index (13.83) compared to the grazed area (12.63). Additionally, the Margaluf richness index showed a significant increase in the exclosure area. Soil phosphorus, potassium, and nitrogen nutrient measurements indicated an increase of 51%, 25.7%, and 15% in the exclosure area (p < 0.05). Correlation analysis revealed a significant linear relationship between organic carbon and phosphorus (r = 0.55) and nitrogen (r = 0.80) (p < 0.05). However, no significant correlation was observed between plant diversity indices and vegetation organic carbon storage. Conclusion: The study demonstrated the positive impact of long-term exclosure on soil and vegetation parameters in mountain rangelands (p < 0.05). Exclosure not only enhanced plant and soil organic carbon storage but also resulted in increased soil nutrient levels, vegetation cover, and diversity and richness indices. The significant increase in plant diversity highlights the suitability of the Simpson index for evaluating diversity in mountain rangelands. However, the lack of a significant linear relationship between diversity index and organic carbon stocks in plants and soils suggests that factors other than plant diversity directly influence carbon stocks in mountain ecosystems. [ABSTRACT FROM AUTHOR]

Nanoparticles (NPs) have received much attention recently in various areas of industry, biomedical, and agricultural sectors worldwide. It is important to recognize the consequences of the use and application of NPs and their interaction with ecosystems components including plants, whether in the environmental area or in physiology and crop production. The present study aimed to investigate the changes in essential oil content and composition of Thymus daenensis Celak., Thymus fedtschenkoi Ronniger and Thymus vulgaris L. under silver nanoparticles (AgNPs) and silicon nanoparticles (SiNPs) in four levels (0, 30, 60, 100 ppm). The essential oil content increased at all stress levels and in all three species. The amount of monoterpene hydrocarbons in T. fedtschenkoi increased, while it decreased in other two species. The amount of sesquiterpentes, except for oxygenated sesquiterpenes in T. daenensis, increased slightly. Compared to other factors, the type of plant species was more determinative in response to treatments. Overall, both AgNPs and SiNps treatments had a distinct effect. However, no interpretable results were observed between the different levels of both treatments. [ABSTRACT FROM AUTHOR]

A pot culture experiment was performed to study the effect of cadmium stress (Cd stress) on seedling growth, physiological traits, and remediation potency of Avena fatua, Lathyrus sativus, and Lolium temulentum. The seedlings of these native rangeland plant species were treated with 0, 2, 4, and 6 mM cadmium nitrate concentrations. Based on the results of analysis of variance (p < 0.05), the shoot height, shoot dry weight, root length, root dry weight, root: shoot ratio, total chlorophyll content, soluble sugars, and protein contentof A. fatua, L. sativus, and L. temulentum significantly decreased with increased cadmium concentrations. Generally, translocation factor (TF) and tolerance index (TI) decreased significantly as the concentration of cadmium increased. The maximum TF and TI of studied plants in various concentrations of Cd were observed in L. temulentum followed by L. sativus and A. fatua. The root concentration factor (RCF) values of all studied plants were higher than 1 under different cadmium concentrations. Our results indicate that Lolium temulentum could be labeled as an accumulator of Cd asthe values of TF and RCF are greater than 1. A. fatua and L. sativus showed a potential to be used in the phytoremediation of Cd-contaminated soils. [ABSTRACT FROM AUTHOR]

The use of vermicompost as a bio-fertilizer and urea (as chemical fertilizer) under drought stress conditions was tested in this research. Accordingly, a pot experiment was carried out and the seedlings of vetivergrass (Vetiveriazizanioidesstapf.) were grown in the greenhouse at Malayer University. The experiment was conducted based on factorial arrangement in a completely randomized design using five replications. Irrigation levels included field capacity (FC) (as control), 60% FC and 30% FC. Vermicompost applications included zero (as control), 40, and 60% which were expressed as VC1, VC2, and VC3. Urea application levels included zero (0), 100, or 200 mg per kg per pot which were expressed as U1, U2, and U3, respectively. The highest and the lowest values of total protein contents (μMg-1 fresh weight (FW)), calcium and magnesium concentrations (mg g−1dry weight (DW)), and survival capacity (%) of the vetivergrass were found in the FC × VC3 × U3 and 30% FC × VC1 × U1 treatments, respectively, whereas the maximum and the minimum values of essential oil contents (%) were seen in the 60% FC × VC3 × U3 and FC × VC1 × U1 treatments, respectively. A different trend was seen in the changes of total chlorophyll content (%) values and the highest and the lowest values were found in the 60% FC × VC3 × U3 and 30% FC × VC1 × U1 treatments, respectively. However, the root dry weight increased significantly as the soil moisture content, percentage of vermicompost, or urea addition decreased. [ABSTRACT FROM PUBLISHER]

The use of vermicompost as a biological fertilizer under salinity stress conditions was tested in this research. Accordingly, the seeds ofMedicago rigidulawere grown in the greenhouse. The experiment was performed based on factorial arrangement in a completely randomized design using 5 replications. Application rates of vermicompost were 0, 10, 20 and 30%. Salinity stress was conducted in three levels (0, 50 and 100 mM sodium chloride (NaCl)). The highest and the lowest values of the plant survival capacity (%), shoot dry weight (g), leaf relative water content (LRWC) (%), total chlorophyll content (%), leaf area (cm2), total nitrogen content (TNC) (%) and potassium (K) content (%) of the plant tissues were found in VC4 × SL1 and VC1 × SL3 treatments, respectively. Whereas, the maximum and minimum values of root dry weight and root:shoot ratio were seen in VC1 × SL3 and VC4 × SL1 treatments, respectively. [ABSTRACT FROM AUTHOR]

A pot experiment based on completely randomized factorial arrangement design with four replications was conducted under greenhouse condition at Malayer University, Malayer, Iran. Pots contained a mixture of soil and different concentrations (0% and 60% w/w) of vermicompost. Plants were exposed to three lead nitrate concentrations: 0, 4, and 8 mM. Based on the results of this research, shoot height and root length of the studied plants significantly decreased with increased lead concentrations in all vermicompost application levels. Generally, plants exposed to lower levels of lead and vermicompost application had higher root:shoot ratio. The survival capacity of all the studied plants was significantly reduced with increased lead concentrations, but increased with increased vermicompost application level. The total protein content increased with decrease in lead nitrate concentration, but decreased with decrease in vermicompost application. Generally, translocation factor increased significantly as vermicompost application rate increased. The highest root concentration factor of lead was found in V1×Pb2 as compared to the other treatment levels. Generally, tolerance index values of all the studied plants were significantly higher in the lower lead concentration treatments. [ABSTRACT FROM AUTHOR]

Levisticum officinaleKoch is one of the most important plants producing essential oil. An experiment was conducted to determine the effect of drought stress on growth, total protein and essential oil content ofL. officinale.The experiment was conducted in a greenhouse, in a completely randomized design using five replications. Aridity levels of field capacity irrigation (as control), −0.6 and −1.0 MPa were applied. There was a significant effect of aridity on the leaf area inL. officinale. The highest leaf area values were found in the lowest aridity (FC) level. The root weight and root length in the −0.6 MPa aridity level were more than that of the control aridity level, but shoot height and shoot weight were highest in the control treatment. The total soluble protein content under −0.6 MPa drought stress was numerically lower than that in the control treatment, but statistically there was no significant difference between protein contents in the −0.6 MPa and the control treatment. Compared to the control treatment, the total soluble protein content ofL. officinalesignificantly decreased in the −1.0 MPa drought treatment. The essential oil content ofL. officinalewas significantly increased in the −0.6 MPa drought treatment compared to the control. Compared to control treatment, a significant reduction was found in essential oil content ofL. officinalein the −1.0 MPa aridity treatment. The results suggest that in the drought levels between −0.6 and −1.0 MPa,L. officinalecould be used for arid and semi-arid lands economical use. [ABSTRACT FROM AUTHOR]

This study was conducted to determine the effects of arbuscular mycorrhizal (AM) inoculation on the leaf relative water content (LRWC), survival capacity, mycorrhizal dependency (MD), essential oil content and total protein content ofMelilotus officinalisgrown in a greenhouse under salinity stress. The experiment was conducted in a completely randomized factorial arrangement design using five replications. Zero (0), 50, 100, 150 and 200 mM sodium chloride (NaCl) and two AM fungal levels were applied. Control (without inoculation) and inoculated (with AM fungi) treatments were considered two mycorrhizal levels. LRWC and survival capacity values in AMMelilotus officinaliswere significantly higher than that in the non-AM-inoculated plants. Generally, MD, essential oil content and total protein content values were significantly higher in the AM-inoculatedMelilotus officinaliscompared with the non-AM-inoculated plants in all treatments. Results suggest thatMelilotus officinaliscould be used for the economic usage of the saline lands. [ABSTRACT FROM AUTHOR]

Mycorrhizal plants often have greater tolerance to drought than non-mycorrhizal plants. This study was conducted to determine the effects of arbuscular mycorrhizal (AM) fungi inoculation on total protein, essential oil content and physiological traits ofGlycyrrhiza glabragrown in a greenhouse under water stress condition. The experiment was conducted in factorial arrangement in a completely randomized design using 5 replications. 100, 80, 60, 40 and 20 % of field water capacity (as water stress levels) and two AM fungal levels were applied. Control (without inoculation) and inoculated (with AM fungi) were two mycorrhizal levels. The highest and lowest leaf area values were found in AM fungi Inoculated treatment with the lowest water stress (% FC) level and 20 % FC without AM inoculation. The maximum percentage values of shoots height and shoots dry weight have been seen in in AM fungi Inoculated treatment with the lowest water stress (% FC). While the maximum percentage values of root length and root dry weight were found in AM fungi Inoculated treatment with 80 % FC water stress. Essential oil content of plants significantly increased in AM fungi Inoculated treatment with 80 % FC water stress. There were significant differences found between essential oil contents of plants at various water stress and mycorrhizal treatments. There was significant difference between total protein content of plants in AM fungi inoculated treatment with FC and 80 % FC water stress and other treatments. Total protein content was reduced from 48 to 5 µM/g FW, for AM fungi inoculated treatment with FC and without AM inoculation treatment with the 20 % FC, respectively. The results suggest thatGlycyrrhiza glabracould be used for arid and semi-arid lands economical use. [ABSTRACT FROM AUTHOR]

In a greenhouse study, the effects of vermicompost and arbuscular mycorrhizal fungi (AM fungi) bio fertilizers on soil properties and Medicago polymorpha growth were studied. The experiment was set up in a completely randomized design in a factorial layout with five replications. The vemicompost treatment was applied in six different levels, including 0, 15, 30, 45, 60 and 75% fertilizer. Further, AM fungi treatment was applied in two levels (inoculating with and without AM fungi). The results showed a decreasing trend in shoot and root dry weight, potassium content, total nitrogen content (TNC), leaf area, leaf relative water content (LRWC), and water holding capacity (WHC) as the vermicompost application rate decreased. In addition, the AM mycorrhizal fungi inoculation significantly increased shoot and root dry weight, potassium content, TNC, leaf area, LRWC, and WHC values and decreased soil bulk density across all vermicompost treatments. However, soil pH and EC were not influenced by AM fungi. Vermicompost treatments also influenced soil properties, including soil pH, electrical conductivity (EC), and bulk density. A higher vermicompost application rate significantly increased soil pH and EC while it decreased soil bulk density. Overall, bio fertilizers showed positive effects on both soil and plant characteristics and could be recommended for management practices to improve plant productivity and soil fertility in grazing lands. [ABSTRACT FROM AUTHOR]