The essential oils of three wild-growing Thymus species, collected from west of Iran during the flowering stage, were obtained by hydrodistillation and analyzed by gas chromatography (GC) and gas chromatography/mass spectrometry (GC-MS). Under the optimum extraction and analysis conditions, 44, 38, and 38 constituents (mainly monoterpenes compounds) were identified in T. kotschyanus Boiss. and Hohen, T. eriocalyx (Ronniger) Jalas, and T. daenensis subsp lancifolius (Celak) Jalas which represented 89.9%, 99.7%, and 95.8% of the oils, respectively. The main constituents were thymol (16.442.6%), carvacrol (7.652.3%), and γ-terpinene (311.4%). Antioxidant activity was employed by two complementary test systems, namely, 2,2-diphenyl-1-picrylhydrazyl (DPPH) free-radical scavenging and β-carotene/linoleic acid systems. Antioxidant activity of polar subfraction of T. daenensis subsp lancifolius (Celak) Jalas was found to be higher than those of the others in DPPH assay, while nonpolar subfraction of T. eriocalyx (Ronniger) Jalas has most antioxidant activity in β-carotene/linoleic acid test (19.1±0.1μg/mL and 96.1±0.8% inhibition rate, resp.).

Water availability is an important factor for plant growth in arid environments. In recent decades, vermicompost (VC) fertilizer has been used in agriculture as a safe and effective fertilizer with high water-holding capacity. The aim of the present study was to characterize effects of VC fertilizer on photosynthetic activity of chickpea (Cicer arietinum L. cv. karaj) under drought conditions at three growth stages. Tests were done at five volumetric ratios of vermicompost to soil: 0:100, 10:90, 20:80, and 30:70; and three levels of drought stress; non-stress (NS), moderate drought stress (MS), and severe drought stress (SS) (100, 75, and 25% of field capacity, respectively). Evaluations were made for chlorophyll content, gas exchange, and chlorophyll fluorescence at different growth stages: a seedling, flowering, and podding stage. Results demonstrated that VC treatment under NS conditions significantly increased total chlorophyll content [Chl (a+b)], intercellular CO₂ concentration (C _i), net photosynthetic rate (P _N), transpiration rate (E), and maximal quantum yield of PSII photochemistry (F_v/F_m) at all three stages. The VC addition at 10 and 20% significantly enhanced Chl content and F_v/F_m under MS and F_v/F_m, C _i, and P _N under SS at the flowering stage. In conclusion, the above results showed that VC fertilizer had a positive effect on photosynthesis of chickpea under NS conditions, but no positive effect was found under MS and SS.

Salinity stress is one of the environmental factors that has many negative effects on the biochemical and physiological processes of the plants. In addition, according to previous reports, nanoparticles have both negative and positive effects on different plant species. The present research evaluated the interaction effects of zinc oxide (ZnO) nanoparticles and salinity stress on two cultivars of Trigonella foenum-graecum. To this end, four levels of salinity and three levels of ZnO nanoparticles were used, followed by measuring some biochemical parameters, trigonelline, antioxidant enzymes, and some elements such as Na, K, Ca, Zn, and Fe. Based on the results, increasing salinity concentration led to a significant increase in proline and malondialdehyde in both cultivars and significantly increased protein while reducing sugar in cv. Mashhadian. At a high concentration of salinity, polyphenol oxidase, peroxidase, lipoxygenase, and phenylalanine ammonia lyase significantly increased in both cultivars. In addition, an increase in salinity concentration increased Na concentration, while it decreased K and Ca concentrations in the shoot and root in both cultivars. Overall, the interaction effects of nanoparticles and salinity stress varied due to different salinity and nanoparticle concentrations, as well as the cultivar type.

The present study was conducted to determine the changes which occurred in the water-stressed fenugreek (Trigonella foenum-gracum L.) in response to melatonin treatment. Fenugreek is a valuable medicinal plant which contains trigonelline as its major alkaloid that plays an osmoregulatory role in abiotic stress. To this end, two experiments were performed. First, the effects of three levels of water deficit were investigated on the physiological and biochemical responses using the PEG 6000. These levels included the NSC (watered with the nutrient solution only), SS (-3 Bar water potential), MS (-5 Bar water potential), and HS (-7 Bar water potential). Then, four concentrations of melatonin were used after selecting the appropriate level for the drought stress (-7 Bar water potential). These levels encompassed the NSC, NTS (19.5% PEG solution only), M50 (50 µM melatonin +19.5% PEG), M100 (100 µM melatonin +19.5% PEG), M300 (300 µM melatonin +19.5% PEG), and M500 (500 µM of melatonin +19.5% PEG). The findings of the first experiment demonstrated that water deficit decreased the weight and length of fenugreek shoots as well as chlorophyll a, chlorophyll b, and carotenoid contents, and catalase activity. In addition, such a deficit led to an increase in proline and trigonelline as osmoregulator and enhanced the activity of other antioxidant enzymes, namely superoxide dismutase (SOD), peroxidase (POD), polyphenol oxidase (PPO), and ascorbate peroxidase (APX). Further, water deficit enhanced endogenous melatonin concentration. Finally, the hydrogen peroxide and malondialdehyde concentrations as well as Reactive Oxygen Species (ROS) also increased under severe stress. The results of the second experiment indicated that melatonin treatment significantly reduced chlorophyll degradation. Furthermore, the activities of the ROS scavenging enzymes such as the SOD, POD, and CAT were increased by melatonin. Moreover, exogenous melatonin led to an increase in endogenous melatonin and trigonelline. These results revealed that fenugreek tolerated water deficit by increasing the endogenous melatonin and trigonelline, as well as the general physiological responses. Additionally, treating the stressed plant with melatonin enhanced the endogenous concentration of the melatonin and trigonelline whereas it led to a decrease in proline content.

One goal in the face of deficit water conditions is to increase growth and yield. Agro-industrial production frequently causes environmental pollution by using chemical fertilizers. In recent decades, bio-fertilizers such as vermicompost have been used as a safe alternative to chemical fertilizer. The present study considered the response of the chickpea to different combinations of vermicompost and water deficit stress in a greenhouse environment. Plant response was determined by measuring a range of morpho-physiologic parameters. The treatments were addition of 0%, 10%, 20%, and 30% of vermicompost to soil, and water deficit stress at the following levels: non-stress (100% of field capacity), moderate water stress (75% of field capacity), and severe water stress (25% of field capacity). The results showed that vermicompost had a significant effect on all traits under stress and non-stress conditions. The vermicompost treatments under non-stress conditions significantly increased plant height, number of pods, leaf area, stem and leaf dry weight, pod dry weight, chlorophyll a, carotenoid, total chlorophyll content, CO₂ assimilation rate, internal CO₂ concentration, and water-use efficiency over that of the control condition. The addition of 30% vermicompost under moderate and severe water stress conditions significantly increased plant height, number of pods, leaf area, leaf dry weight, carotenoids, and water-use efficiency over that of the control level. This study confirmed that vermicompost improved the morphological features, soil biological activity, and quality of the chickpea, but did not positively influence the physiological features under moderate and severe water deficit stress.

GC–MS analyses of the essential oils of leaves, stems and flower of Nasturtium officinale resulted in the identification of 9, 8 and 15 compounds, representing 97%, 100% and 94.7% of the oils, respectively. The main compounds of the oil of leaves were myristicin (57.6%), α-terpinolene (8.9%) and limonene (6.7%). Caryophyllene oxide (37.2%), p-cymene-8-ol (17.6%), α-terpinolene (15.2%) and limonene (11.8%) were the main components in stems, whereas limonene (43.6%), α-terpinolene (19.7%), p-cymene-8-ol (7.6%) and caryophyllene oxide (6.7%) were the major constituents in the oil of flowers. All the samples were subjected to a screening for their possible antioxidant activities using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and β-carotene-linoleic acid assays. In the above tests, methanol extracts of leaves showed higher antioxidant activity than the oils and methanol extracts of stems and flowers.