Salinity stress is one of the major limiting factors affecting seed germination and early establishment of crop plants, including maize.Salinity reduces growth, decreases relative water content and photosynthetic pigments, and increases stress related indicators, thereby impairing the physiological stability of seedlings.Seed priming with salicylic acid, as a plant growth regulator, may modulate plant responses to abiotic stresses.The objective of this study was to evaluate the effect of salicylic acid seed priming on germination, early growth, and selected physiological and biochemical traits of maize (cv.Single Cross704) under salinity stress.The experiment was conducted in the Plant Physiology Laboratory as a factorial arrangement in a completely randomized design with five replications.Treatments included four salinity levels (0,50,100, and 150mM) and five concentrations of salicylic acid (0,0.25,0.5,0.75, and 1mM).Seeds were surface-sterilized, primed with salicylic aci solutions, and then incubated in a germinator (25±1°C, darkness) for 10 days.Measured traits included germination percentage, root and shoot length, fresh and dry weight, relative water content, total chlorophyll, proline, and malondialdehyde.Data were analyzed using two-way ANOVA.Increasing salinity significantly reduced germination and growth traits, relative water content, and total chlorophyll, while significantly increasing proline and malondialdehyde levels.The main effects of salinity, salicylic acid, and their interaction were significant at the1% probability level for all measured traits.Seed priming with salicylic acid mitigated the adverse effects of salinity.The greatest improvement in growth, RWC, and chlorophyll content, along with the greatest reduction in proline and MDA, was observed at 0.75mM salicylic acid.In contrast, the 1mM concentration showed lower effectiveness, indicating a concentration-dependent response.The results indicate that salicylic acid seed priming under controlled conditions can alleviate the severity of salinity stress during the seedling stage and improve the physiological status of maize.The identification of 0.75mM as the optimal concentration highlights the importance of precise dosage management.
To investigate the combined effect of conservation tillage and mulch on physiological activities and drought tolerance induction in faba bean, a field experiment was conducted at the research farm of the Faculty of Agriculture, University of Wasit, Iraq, during the 2023-2024 growing season. The experiment was designed as a split-plot based on a randomized complete block design with four replications. The treatments included drought stress at three levels (40%, 70%, and 100% of field capacity) and conservation tillage at four levels (NTM: no-tillage with mulch, NT: no-tillage without mulch, CTM: conventional tillage with mulch, CT: conventional tillage). The results showed that drought stress significantly reduced the relative water content of leaves, chlorophyll a and b, number of pods per plant, number of seeds per pod, 100-seed weight, and seed yield, while it increased the activity of antioxidant enzymes (catalase, peroxidase, superoxide dismutase), proline, and abscisic acid. The application of conservation tillage with mulch (NTM) compared to conventional tillage (CT) significantly mitigated these negative effects across all drought stress levels.Under severe drought stress (40% field capacity), the NTM treatment, compared to CT, increased physiological traits, including relative water content of leaves, chlorophyll a, chlorophyll b, catalase, peroxidase, and superoxide dismutase by 41.9%, 56.6%, 53.3%, 16.9%, 35.3%, and 28.8%, respectively. It also resulted in a 36.5% increase in the number of pods per plant, 54.9% in the number of seeds per pod, 15.4% in 100-seed weight, and 57.4% in seed yield. Therefore, the use of conservation tillage with mulch (NTM) is recommended as a sustainable and highly effective strategy, not only for mitigating the adverse effects of drought stress but also for enhancing physiological processes and significantly improving seed yield in faba bean cultivation, particularly under challenging water-scarce conditions.
Plants encounter various stressors during their growth period, the effects of which on plant growth and performance vary depending on the intensity of the stress, the sensitivity of the plant species, and the growth stage. This study was conducted to investigate the effects of cerium oxide nanoparticles (CeO₂) at different concentrations (0, 2, and 4 mmol/L) on purslane (Portulaca oleracea) under heavy metal lead stress at three concentrations (0, 200, and 400 mg/kg of soil), using a completely randomized design with three replicationsIn a pot experiment. The nanoparticle treatment was applied via foliar spraying. The results revealed that different concentrations of lead and cerium oxide nanoparticles had significant effects on most morpho-physiological traits, including root length, fresh and dry stem weight, dry root weight, root volume, chlorophyll a, chlorophyll b, total chlorophyll, carotenoids, antioxidants, total phenolics, and flavonoids. The findings indicated that increasing lead concentration resulted in a decrease in growth indices such as root length, fresh stem weight, dry root weight, chlorophyll a, chlorophyll b, and total chlorophyll, while total phenolics, flavonoids, and antioxidants increased. Purslane was able to maintain its growth factors, such as stem length, fresh and dry stem weight, fresh and dry root weight, root volume, chlorophyll b, total phenolics, flavonoids, and antioxidants at a lead concentration of 200 mg/kg, demonstrating its tolerance to heavy metal stress at lower concentrations. Cerium oxide nanoparticles at a concentration of 4 mmol/L had the most significant impact on improving the growth and performance indices of purslane. The interaction between cerium oxide nanoparticles and lead indicated that a concentration of 4 mmol/L nanoparticles had the greatest effect in mitigating the harmful effects of lead and significantly enhanced antioxidant activity. Therefore, it can be concluded that foliar application of cerium oxide nanoparticles at a concentration of 4 mmol/L is an effective method to reduce the adverse effects of lead stress, improve physiological and biochemical processes, and enhance the tolerance of purslane to lead-induced stress.
Global agriculture increasingly requires resilient crops like quinoa to address challenges such as climate change and soil salinity. Although quinoa possesses inherent tolerance to abiotic stresses, high salinity still significantly inhibits its growth and yield. This study investigated the efficacy of silicon nanoparticles (SiO₂-NPs) in mitigating salt stress in quinoa (cv. Q12). An experiment employed a factorial design with three salinity levels (0, 200, 400 mM NaCl) and three SiO₂-NPs concentrations (0, 50, 100 mg L⁻¹). Salinity stress was applied gradually, followed by foliar application of nanoparticles. Measurements included growth parameters and key biochemical traits. Results confirmed that salinity severely reduced plant growth (height, root length, biomass) and photosynthetic pigment content (chlorophyll a, b, carotenoids). It also induced oxidative stress, marked by elevated levels of malondialdehyde (MDA) and hydrogen peroxide (H₂O₂), though secondary metabolites (phenols, flavonoids, anthocyanins) increased as a defence response. Application of SiO₂-NPs, particularly at 100 mg L⁻¹, effectively counteracted these adverse effects. It significantly improved all growth indices and enhanced photosynthetic pigment content by up to 50% under high salinity. Concurrently, it reduced oxidative stress markers (MDA by 21%, H₂O₂ by 18%) and further boosted antioxidant compounds. The findings demonstrate that SiO₂-NPs enhance quinoa's salt tolerance through a multi-faceted mechanism: improving photosynthetic efficiency, reinforcing the non-enzymatic antioxidant system, and protecting cellular membranes from oxidative damage. This supports the use of silicon nanoparticles as a sustainable strategy for cultivating quinoa in saline marginal lands, thereby contributing to global food security.
Drought stress is one of the limiting factors of plant production, but the application of micro and superabsorbent fertilizers can increase drought resistance in plants. In order to investigate the effect of superabsorbent and complete micro fertilizer on some physiological characteristics and grain yield of mung bean under drought stress, an experiment was conducted in the form of split plots in a randomized complete block design with three replications. The main plot included irrigation interruption stress with three levels including: complete irrigation, interruption of irrigation before flowering and interruption of irrigation after flowering and the subplot of superabsorbent polymer with three levels including: zero (control), 75 and 150 kg/ha and the subplot of complete micro fertilizer foliar application with three levels of zero (control), two per thousand and four per thousand. The results showed that the triple interaction of irrigation interruption in superabsorbent polymer in foliar application of complete micro fertilizer was significant on the traits of number of grains per pod and grain yield. The highest grain yield (2601.2 kg/ha) was obtained under full irrigation conditions with the use of 150 kg/ha of superabsorbent and 4% micro fertilizer foliar application, which showed a 52% increase compared to the treatment of stopping irrigation at the flowering stage and not using superabsorbent and micro fertilizer foliar application. Also, the interaction of stopping irrigation on superabsorbent on superoxide dismutase, catalase, proline and chlorophyll index was significant. The highest superoxide dismutase and catalase enzymes were obtained under conditions of stopping irrigation at the flowering stage and spraying micro fertilizer with a concentration of 4% by weight. Under different moisture stress conditions, 150 kg/ha of superabsorbent polymer and 4% micro fertilizer foliar application should be used to increase grain yield and physiological traits in mung bean plants.
Rosemary (Rosmarinus officinalis L.) is an evergreen, aromatic plant belonging to the Lamiaceae family, with leaves and flowering shoots containing volatile essential oils. To enhance secondary metabolite production, elicitors such as silver nanoparticles are used, which influence cellular signaling pathways and increase the synthesis of these compounds in tissue cultures. In this study, callus induction from leaf explants was performed on MS medium supplemented with NAA (0, 0.5, 1, and 2 mg/L) and BAP (0, 1, and 2 mg/L) in a factorial completely randomized design with four replications. The optimal combination (2 mg/L NAA and BAP, yielding 92% callus induction) was selected. Subsequently, the effect of silver nanoparticles (0, 2, 5, 10, and 15 mg/L) was evaluated in a completely randomized design with three replications. Results showed that silver nanoparticles increased fresh and dry callus weight by 28% and 35%, respectively. The highest concentrations of total phenols, flavonoids, and rosmarinic acid were observed at 2 mg/L, while higher concentrations reduced these traits. Concentrations of 2 and 5 mg/L increased chlorophyll a and b, whereas 15 mg/L decreased them. The highest antioxidant capacity (15% increase compared to control) was achieved at 2 mg/L. Therefore, 2 mg/L silver nanoparticles combined with NAA and BAP hormones is recommended for enhancing callus induction and secondary metabolite production in rosemary.
Oilseed rape grain yield highly associated with nitrogen rating and plant density in which by increasing in its levels, all other quantitative and qualitative traits would be influenced. The aim of this study was to assessment the effects of plant growth regulators (control, Medax top, Superstem) under different nitrogen rating (based on soil test recommendation, 50% more than soil test recommendation and 100% more than soil test recommendation) and plant density (including 50 and 100 plant per m-2) based on factorial split plot design replicated thrice during 2018-2019 and 2019-2020. The analysis of variance revealed that all evaluated traits was effected by experimental treatments and their interactions (P>0.01), except thousand grain yield. The highest grain yield (2954 kg/ha), oil yield (1040 kg/ha) and protein content (29%) were obtained in 50 plant per m-2×without application of plant growth regulators×50% more than soil test recommendation interaction. Generally, the results depicted that application of plant growth regulators under higher nitrogen and plant density conditions caused growth retardation and decreased plant height, meanwhile it is dwindled grain and oil yield as well as protein content, dramatically.
Nutritional management plays a crucial role in enhancing the ecological functions of green walls. In this regard, a study was conducted in the autumn of 2022 in Mashhad, aimed at evaluating the effects of fertilizer sources on the morphophysiological characteristics of Daisy (Bellis perennis) in green wall conditions. The experiment was planned on the factorial statistical design based on the randomized complete block design with three replications. The first treatment was potassium nitrate fertilizer (in four doses: 0, 1, 3, and 6 mM), and the second treatment was zinc sulfate (in four doses: 0, 1, 2, and 4 μM). The results showed that the use of zinc sulfate and potassium nitrate significantly increased growth and improved plant performance compared to the control group. The findings indicate that fertilization with 6 millimolar potassium nitrate and the simultaneous application of 4 micromolar zinc sulfate resulted in the highest growth indices, including the tallest plant height (14 cm), flower bud diameter (12 mm), number of flower buds (4.7), flower bud length (9.2 mm), number of flowers (9 per plant), peduncle length (30 mm), flower length (17 mm), number of leaves (35), SPAD index (48), fresh flower weight (1.8 g), and dry flower weight (1.3 g). The highest total chlorophyll content (5.7 μg/mg) in both fertilizers was observed in the highest concentration treatment, whereas the highest carotenoid content (0.8 μg/mg fresh weight) and electrolyte leakage (53.86%) were recorded in the non-fertilized treatment. The application of 6 millimolar potassium nitrate and 4 micromolar zinc sulfate is recommended for daisy cultivation in green walls. These findings suggest that the combination of these fertilizers can improve the growth and aesthetic appeal of external green walls and present a suitable approach to promoting the use of ornamental plants in urban spaces.
In order to investigate the effect of triazole growth regulators on the yield and some physiological and morphological traits of potato under drought stress conditions, a split-plot experiment was conducted based on randomized complete block design with three replications in 2020-2021, in Sarab region, East Azarbaijan province, Iran. The experimental treatments were included irrigation as the main plot with three levels including the control (100% field capacity), 75% field capacity and 50% field capacity) and a sub-plot including triazoles in five control levels (no use of triazole), Penconazole, Hexaconazole, Propiconazole and Paclobutrazol). The results showed that the effect of triazole and the interaction effect of drought stress x triazole on all studied traits were significant, while drought stress was not significant on the traits of stem diameter, lAI, chlorophyll and starch contents. Also, with the increase of drought stress, the phenol, starch and proline contents increased and RWC and chlorophyll content decreased. Also, tuber yield, tuber size, stem height and LAI decreased and dry matter percentage increased. However, the effect of triazole treatments on different traits was diverse, so that even in some traits, the control treatment was superior to the triazole treatments at each stress level. In other words, the use of triazole had a lesser role in potato compared to drought stress. Probably, the lack of significant effect of triazoles on the studied traits is due to the following reasons: First, potato is a very sensitive plant to drought, so the response of this plant to drought stress was more prominent than triazoles. The second reason is that maybe the amount of triazoles used (15 mg/liter) was not enough to cause changes in the plant, so it is recommended to use higher concentrations.
Choosing the right growing medium and plant nutrition is one of the key aspects of a green roof in order to achieve its important ecological functions. This experiment was conducted on Catharanthus roseus in the spring and summer of 2022 under the green roof conditions of Mashhad in a factorial manner in a randomized complete block design with 3 replications. The first treatment was nitrogen fertilizer (ammonium sulfate and sulfur urea in three doses of zero, 25 and 50 grams per square meter) and the second treatment was the type of culture medium (containing soil and without soil). The results showed that Madagascar periwinkle does not show a noticeable reaction to the presence or absence of soil in the cultivation growing medium. But the use of nitrogen fertilizer significantly improves plant growth and performance. The lowest salinity (about 1 decisiemens per meter) and the lowest acidity of the culture medium (about 7) were observed with the application of all concentrations of two nitrogen fertilizers, and the reduction of the acidity of the culture medium by the fertilizer leads to better absorption of nutrients by the plant and improvement of physiological traits, including an increase in leaf water content. (up to 100%), decreased electrolyte leakage (up to 90%), increased chlorophyll (up to 2.5 μg/mg) and improved photosynthesis. Subsequently, the highest number of flowers (53 per plant), growth index (12000 square centimeters), fresh and dry weight of shoots (120 and 26 grams, respectively), fresh and dry weight of roots (4.5 and 1.3 grams, respectively) in Urea sulfur treatment was seen. 25 grams per square meter of ammonium sulfate and urea-sulfur fertilizers and both types of growing medium are recommended for growing Madagascar periwinkle plants on the green roof.
In aquatic ecosystems, as the richest collection of living organisms, microalgae are amy, which play an essential role in the process of water and wastewater quality. One of the most famous microalgae is Chlorella vulgaris microalgae. Chlorella vulgaris microalgae (Chlorella vulgaris) has been widely used for wastewater treatment. According to this microalgae, it has a high ability to remove chemical pollutants, reducing the noticeable ability and removing bacteriological pollution. In this research, the antibacterial effect of Chlorella vulgaris microalgae (Chlorella vulgaris) in different seasons on Esherichia coli bacteria was investigated. Zinder special culture medium was used for the cultivation of Chlorella vulgaris microalgae. After the preparation and cultivation of Chlorella vulgaris microalgae, the antibacterial effects of this algae and the minimum concentration of inhibiting the growth of microbes were determined using the tube dilution method against bacteria (Esherichia coli). The results showed that Chlorella vulgaris microalgae (Chlorella vulgaris) has significant inhibitory properties against bacteria (Esherichia coli). Also, there was a significantcorrelation between the time of the microalgae Chlorella vulgaris (Chlorella vulgaris) and the number of removal bacteria (Esherichia coli). Chlorella vulgaris (Chlorella vulgaris) microalgae in the autumn and winter seasons at a concentration of 10 mg/l for 30 to 40 minutes and in the hot seasons of the year at a concentration of 8-10 mg/l led to a reduction of about 50% of Escherichia coli. ) bacteria with MPN equal to 54 .mg/l Extended abstract Introduction Microalgae are essential in aquatic ecosystems as the base of food chains and have extensive industrial applications. Optimizing their growth requires selecting appropriate species and nutrient-rich culture media, which enhances the production of bioactive compounds. Recently, microalgae have been increasingly applied for wastewater treatment due to their environmental safety, nutrient recycling, and biomass utilization. Wastewater, rich in nutrients like nitrogen and phosphorus, heavy metals, hydrocarbons, and pathogenic microorganisms, poses a contamination risk if untreated. Chlorella, a green microalga, can grow under diverse conditions and exhibits antibacterial, antifungal, and anticancer properties. This study aimed to evaluate the ability of Chlorella vulgaris to reduce Escherichia coli in wastewater treatment plants in Gilan Province, meeting WHO standards for safe water reuse. Materials and Methods Monthly wastewater samples were collected for one year using sterile polyethylene containers with sodium thiosulfate. Pure Chlorella vulgaris stock cultures were grown in Zinder medium under controlled conditions (25 ± 2°C, 2500 lux light, 12 h light/12 h dark). Microalgal growth was monitored over 21 days via optical density at 750 nm, and cell counts were performed with a Neubauer chamber. The antimicrobial effect of Chlorella vulgaris against E. coli was tested using agar plate counts and broth dilution methods with concentrations ranging from 2–10 mg/L. The MPN method assessed bacterial reduction over varying exposure times, and statistical significance was evaluated at 5% using SPSS. Results and Discussion Chlorella vulgaris significantly reduced E. coli growth. At 10 mg/L, bacterial counts decreased by 50% within 30 minutes and reached over 90% after 45–60 minutes. Seasonal variations were observed: warmer months with higher initial bacterial loads led to greater reductions, whereas colder months required longer exposure times. The logarithmic growth phase of Chlorella produced metabolically active cells that were most effective in bacterial suppression. The reduction of E. coli is attributed to competition for nutrients, CO₂ consumption by microalgae, and pH elevation, which inhibit bacterial growth. Environmental factors such as light intensity, temperature, and wastewater composition influenced the efficiency of bacterial removal. These results align with previous studies showing that higher microalgal concentrations and optimal environmental conditions enhance antimicrobial effects. Conclusion Chlorella vulgaris demonstrates strong potential as an eco-friendly agent for reducing pathogenic E. coli in wastewater. Its effectiveness depends on microalgal concentration, exposure time, and environmental conditions, including light and temperature. Beyond wastewater treatment, Chlorella biomass offers applications in bioactive compound production, biofuels, and agriculture. Future studies should optimize large-scale cultivation and investigate additional microalgal strains for efficient bacterial removal.
An important aspect of agricultural planning is the evaluation of various plant nutrition systems. This research aimed to investigate the effects of foliar spraying with growth stimulants and specific nutrients on several agronomic and physiological traits of soybean under conditions of pest control and non-control. The study was conducted in the fields of Aliabad-e Katul and Aragheh Mahalle in 2017. The research followed a factorial design in a randomized complete block format with three replications. The experimental treatments consisted of pest presence at two levels (with and without sucking pests) and eight foliar spraying treatments: 90% Neutramin amino acid, seaweed extract, humic acid, boron, amino acid + boron, seaweed extract + boron, humic acid + boron, and a control group (no foliar spraying). Results indicated a significant decrease in production when pests were present. The highest number of seeds per pod and seeds per plant was recorded at the Aliabad-e Katul station when pests were absent. Additionally, foliar spraying with seaweed at this station resulted in a higher hundred-seed weight. In contrast, the Aragheh research station in the Gorgan district showed lower biological yield and a higher harvest index compared to Aliabad-e Katul. Furthermore, the application of foliar spraying boron with a combination of amino acid + boron increased the protein and oil content in soybeans.
Considering the importance of the effect of drought stress and the role of zinc on growth characteristics of Digitalis purpurea, a factorial experiment based on a randomized complete block design with 10 replications was conducted on Digitalis purpurea at Ferdowsi University of Mashhad during at 2019. Drought stress treatments were carried out at two levels of 50 and 100 percent of field capacity and type of zinc fertilizer (at 7 levels of 0, 0.5, 1, and 2 g/L of zinc nano-chelate and 0.5, 1, and 2 g/L of zinc sulfate) as foliar sprays starting at the 5-leaf stage and repeated every 15 days. The results showed that foliar spraying with 2 mg/L of zinc nano fertilizer and no application of stress (FC 100%) zinc resulted in the highest leaf area (1300 mm2), height (24 cm), number of leaves (110), rosette stem diameter (48 mm) and flowering stem diameter (79.5 mm), crown diameter (30 mm) and corolla diameter (125 mm) of Digitalis purpurea. While applying 50% FC stress and no fertilizer application, the highest levels of carotenoids (3.8 μg/mg wet weight), phenols (6 μg/mg wet weight) and antioxidants (55%) were observed. However, the application of 2 mg/L of zinc nano fertilizer was able to prevent the increase in carotenoid, phenol, and antioxidant levels, and the highest levels of chlorophyll a (10.8 μg/mg wet weight), chlorophyll b (5.5 μg/mg wet weight), total chlorophyll (15.5 μg/mg wet weight), and total pigment (15.68 μg/mg wet weight) were evident in the 100% FC treatment and the application of 2 mg/L of zinc nano chelate. In arid and semi-arid regions, with the application of supplementary nutrition of 2 mg/liter of zinc nano fertilizer, one can expect good quality from Digitalis purpurea . Extended abstract Introduction Digitalis, a medicinal and ornamental plant of the Scrophulariaceae family, contains digoxin, an important cardiac glycoside. Drought stress is a major abiotic factor limiting plant growth, particularly affecting flowering and seed production. Zinc plays a crucial role in enzymatic activity, chlorophyll synthesis, and stress tolerance, while zinc-based nano-fertilizers have shown potential in improving nutrient uptake and plant performance. Therefore, investigating the effects of drought and zinc nutrition on the morphological and physiological traits of Digitalis is essential for optimizing its cultivation. Materials and Methods A factorial experiment based on a completely randomized design with ten replications was conducted to evaluate the effects of drought stress (50% and 100% field capacity) and zinc fertilizers (nano chelate and sulfate forms at 0, 0.5, 1, and 2 g/L) on Digitalis purpurea. Seeds were germinated in cocopeat-perlite trays and transplanted into 7 kg pots containing a loamy soil mixture. Zinc treatments were applied as foliar sprays at the five-leaf stage every 15 days for three applications. Morphological traits (leaf number, leaf area, plant height, stem and flower diameters, crown diameter) and physiological traits (chlorophyll, carotenoids, total phenol, and antioxidant activity) were measured. Data were analyzed using JMP8 software, and mean comparisons were performed with Tukey’s test at p ≤ 0.05. Results Drought stress significantly reduced leaf area, plant height, and flower and crown diameters, while nano-zinc treatments, particularly at 2 g/L, enhanced these traits compared to zinc sulfate. Chlorophyll and total pigment contents were higher under well-watered conditions and nano-zinc application, whereas drought stress increased phenol and antioxidant levels. Correlation analysis revealed strong positive relationships among morphological traits and significant associations between physiological traits and pigments, phenol, and antioxidant activity. Overall, nano-zinc fertilizers were more effective than conventional zinc sulfate in mitigating the negative effects of drought stress on Digitalis purpurea. Conclusion Drought stress significantly reduced leaf area, plant height, flower and crown diameter, and total chlorophyll in Digitalis purpurea, mainly due to stomatal closure and limited photosynthesis. Zinc application, particularly in nano form, enhanced leaf growth, chlorophyll content, and biomass by stimulating auxin production, enzymatic activities, and nutrient uptake. Phenolic compounds and antioxidant activity increased under drought stress, indicating activation of protective mechanisms, while zinc treatments mitigated oxidative damage. Overall, nano-zinc fertilizers improved morphological and physiological traits and helped plants tolerate drought more effectively than conventional zinc sources.
The presence of toxic silver levels in the environment significantly affects the physiological changes in plants, severely impacting their growth capabilities. In cases where silver concentrations are extremely high, this pollution can lead to the destruction of sensitive plant species. Under such conditions, sensitive plants may suffer damage due to the toxic effects of silver and, in some instances, die; however, silver-resistant plants can continue to grow and reproduce despite such contamination. The aim of this research was to investigate the effects of high silver concentrations on various characteristics of the harmel plant, including the length of aerial and root organs, the dry weight of these organs, silver accumulation, and the transfer factor. To achieve this, harmel plants were exposed to varying concentrations of silver (0, 1, 5, 10, 20, 40, and 80 mg/L) for 15 days. The results indicated that increasing silver concentrations led to reduced lengths of both aerial and root organs, as well as a decrease in the dry weight of these organs. However, the level of silver accumulation in both aerial and root organs clearly increased. Furthermore, the transfer factor significantly increased in response to different silver concentrations compared to the control treatment. Consequently, the findings suggest that the harmel plant possesses a high capacity for silver accumulation and tolerance, making it a suitable candidate for silver phytoremediation. These findings are particularly important for developing environmental management methods and reducing pollution caused by heavy metals.
Salinity stress is a significant factor that diminishes plant yield globally. Humic acid, as an organic acid, plays a crucial role in enhancing plant yield under salt-stress conditions. To investigate the effects of salinity stress and humic acid fertilization on corn plants, a pot study was conducted with three replications using a factorial experimental design in a completely randomized layout. Treatments included salinity stress at two levels (no stress and 100 mM stress) and humic acid fertilization at three levels (no fertilization, 100 mg/L fertilization, and 200 mg/L fertilization). This study aimed to investigate the effects of humic acid fertilization on the morphological and physiological traits of corn plants under salt stress conditions and to evaluate the role of humic acid in improving the mentioned traits and reducing the harmful effects of salt stress in corn plants, as an important plant in terms of human food supply. The results indicated that salinity stress significantly reduced stem height and total chlorophyll levels in corn plants, while treatment with humic acid effectively mitigated the detrimental effects of salinity. At 100 mM salinity, the application of 100 mg/L humic acid fertilizer increased stem height by 26.6% compared to no application. Also, under 100 mM salinity stress, the total chlorophyll content increased more than twice when fertilizing with 200 mg/L humic acid compared to no fertilization. Based on the findings of this study, humic acid is recommended to promote the vegetative growth of corn plants under salt stress conditions. Extended Abstract Introduction Maize (Zea mays L.) is one of the most important cereal crops worldwide, with an annual production exceeding one billion tons, and plays a key role in human nutrition, animal feed, and industrial applications. Environmental stresses disrupt normal physiological processes in plants, leading to growth reduction and yield losses. Among abiotic stresses, salinity is one of the most serious constraints to agricultural production, particularly in arid and semi-arid regions. More than six percent of the world’s land area and a considerable proportion of irrigated agricultural lands are affected by salinity, and this trend is continuously increasing. Salinity stress induces morphological, physiological, and biochemical alterations in plants, including reduced root and shoot growth, decreased photosynthetic pigments, impaired photosynthesis, and changes in osmotic regulation. Previous studies have reported a reduction in plant height, chlorophyll content, and biomass in maize under salinity stress, while increases in soluble sugars and anthocyanins have also been observed as adaptive responses. Humic acid, as an organic soil amendment, has gained attention for its ability to improve soil physical and chemical properties, enhance nutrient availability, and modulate plant physiological responses under stress conditions. Therefore, the present study aimed to investigate the effects of humic acid application on selected morphological and physiological traits of maize plants under salinity stress. Materials and Methods This experiment was conducted as a pot trial during autumn 2023 under open-field conditions in Behbahan, Khuzestan Province, Iran. The experiment was arranged as a factorial based on a completely randomized design with three replications. Treatments consisted of two salinity levels (0 and 100 mM NaCl) and three humic acid concentrations (0, 100, and 200 mg L⁻¹). Maize hybrid cultivar ‘Ajeeb’ was used in this study. Salinity stress was applied two weeks after seedling establishment, while humic acid treatments began one day before stress imposition and were repeated every three days. To prevent salt accumulation, pots were leached with tap water after every two saline irrigations. Morphological traits (plant height and root volume) and physiological parameters including photosynthetic performance index (PI), SPAD chlorophyll index, chlorophyll a, b and total chlorophyll, carotenoids, soluble sugars, and anthocyanin content were measured 30 days after treatment application. Data were statistically analyzed using two-way analysis of variance (ANOVA), and mean comparisons were performed using Duncan’s multiple range test at the 5% probability level. Results and Discussion Salinity stress significantly reduced several morphological and physiological traits of maize plants. A marked decline in photosynthetic performance index (PI), SPAD value, and chlorophyll a content was observed under salinity, indicating impairment of the photosynthetic apparatus. Application of humic acid mitigated the adverse effects of salinity. Under salinity stress, application of 100 mg L⁻¹ humic acid increased plant height compared to the non-treated control, while 200 mg L⁻¹ humic acid significantly enhanced root volume. The interaction between salinity and humic acid had a significant effect on total chlorophyll content, such that under salinity stress, application of 200 mg L⁻¹ humic acid more than doubled total chlorophyll compared to the untreated plants. Carotenoid content increased with humic acid application, suggesting a protective role against oxidative damage caused by salinity. Although the effects of salinity and humic acid on soluble sugar and anthocyanin contents were not statistically significant, both parameters showed increasing trends in humic acid-treated plants. This response may be associated with improved osmotic adjustment and enhanced antioxidant capacity under stress conditions. Overall, the results indicate that humic acid improves nutrient uptake, stabilizes chloroplast structure, enhances photosynthetic pigments, and promotes root growth, thereby increasing maize tolerance to salinity stress. Conclusion Salinity stress negatively affected growth and photosynthetic efficiency of maize plants. However, humic acid application effectively alleviated the detrimental effects of salinity by improving morphological and physiological characteristics. Among the tested treatments, application of 200 mg L⁻¹ humic acid was the most effective in enhancing root volume and photosynthetic pigment content under salinity stress. Therefore, humic acid can be recommended as a practical and environmentally friendly strategy to improve maize growth and stress tolerance in saline soils.
In the present study, the effect of nitrogen fertilizers, including urea, NPK, and biofertilizer containing Azotobacter with the trade name Dr. Bio, on growth, content of some elements, and content of flavonoid compounds and total anthocyanins in the ornamental-medicinal plant Zamioculcas zamiifolia Engl. was investigated. In the greenhouse of Farhikhtegan at Islamic Azad University of Gorgan, plants were planted in pots and arranged in random blocks under the influence of different concentrations of fertilizer, specifically at levels of 0, 2, and 4 g/L. Urea and biofertilizer treatments had more significant effects on growth factors, such as the fresh and dry weights of roots and leaves, compared to NPK fertilizer. Although the flavonoid content of leaves was not affected by fertilizer, biofertilizer had a significant positive effect on the anthocyanin content of them. Concentrations of 2 g/L of NPK or urea negatively affected the total anthocyanin content of leaves, while a concentration of 4 g/L of urea had a positive effect. All treatments positively increased the nitrogen content in roots. The total nitrogen in leaves was unaffected by the biofertilizer, but showed some increases with other treatments. Both biofertilizer and urea had significant positive effects on increasing the nitrate reductase activity in leaves. The effect of NPK fertilizer on this enzymatic activity was increased at a concentration of 4 g/L but decreased at a concentration of 2 g/L. All treatments significantly reduced phosphorus and potassium levels in leaves while increasing them in the roots. Both biofertilizer and NPK significantly reduced the iron content in both leaves and roots. However, with urea, this decrease was only observed in the roots at a concentration of 2 g/L. In contrast, the 4 g/L treatment increased the iron content in both the roots and leaves. Introduction:Zamioculcas zamiifolia is a popular ornamental and medicinal plant due to its aesthetic appeal and high tolerance to adverse conditions. Nitrogen nutrition plays a critical role in improving plant growth and physiological performance; however, the effects of different nitrogen sources on this species have not been fully elucidated. This study aimed to evaluate the effects of three nitrogen-containing fertilizers urea, compound NPK fertilizer, and the biological fertilizer on growth indices, nitrate reductase enzyme activity, secondary metabolites (flavonoids and anthocyanins), and mineral composition of Z. zamiifolia under greenhouse conditions. Materials and Methods:The experiment was conducted under controlled greenhouse conditions. Zamiifolia plants were treated with three fertilizer types (urea, NPK) at concentrations of 0 (control), 2, and 4 g L⁻¹. Growth parameters, including fresh and dry weights of leaves and roots, were measured. Nitrate reductase activity was assessed to evaluate nitrogen metabolism, while flavonoid and anthocyanin contents were determined using spectrophotometric methods. In addition, mineral elements (nitrogen, phosphorus, potassium, and iron) were measured in leaves and roots to assess nutrient uptake and translocation. Results and discussion:Urea and Biofertilizers significantly enhanced plant growth and were superior to NPK in increasing fresh and dry weights of leaves and roots. Nitrate reductase activity was markedly higher in plants treated with urea and the biological fertilizer, indicating improved nitrogen uptake and metabolism. Although total flavonoid content was not significantly affected by fertilizer treatments, leaf anthocyanin content increased significantly under the biological fertilizer treatment. Root nitrogen content increased in all fertilizer treatments, whereas leaf nitrogen responses varied depending on fertilizer type. Leaf phosphorus and potassium contents decreased, while their concentrations in roots increased, suggesting nutrient translocation. Iron content generally declined, except in the 4 g L⁻¹ urea treatment, which resulted in increased iron levels in both roots and leaves. Conclusion:The results demonstrated that urea and the biological fertilizer were more effective than NPK in improving growth, nitrogen metabolism, and certain physiological traits of Zamioculcas zamiifolia. The biological fertilizer also enhanced anthocyanin accumulation, which may contribute to greater stress tolerance and ornamental value. Given these advantages, the use of urea and biological fertilizers is recommended for greenhouse cultivation of zamiifolia, although further studies are required to evaluate long-term effects and environmental sustainability.
Abiotic constraints, such as salinity stress, reduce cereal production. Exogenous application of salicylic acid (SA) can prevent the harm caused to rice by salinity, but the mechanisms by which it increases the tolerance of rice under salinity stress conditions are unclear. In this research, the effect of external application of SA on the growth and biochemical traits of rice plants under salinity stress was investigated as a factorial experiment based on a completely randomized design in hydroponic conditions. The results showed that salinity stress decreased photosynthetic pigments (chlorophyll and carotenoids), K/Na ratio, and glutathione-ascorbic acid redox state, and, as a result, rice plant growth. However, the application of SA improved the growth and height of rice plants by reducing the accumulation of hydrogen peroxide and malondialdehyde and increasing the activity of antioxidant enzymes. By maintaining K/Na homeostasis and glutathione-ascorbic acid redox states, SA improved plant tolerance and increased photosynthetic pigments in rice plants. SA also increased the accumulation of osmolytes, including free proline and soluble sugars, which can play an important role in modulating the osmotic potential of plant cells under salt stress. The obtained results show that the positive effects of the external application of SA on the accumulation of osmolytes, the K/Na ratio, and the antioxidant defense system lead to increased tolerance to salinity and improved growth of rice plants under salinity stress.
An experiment was conducted to evaluate the effect of water stress on the physiological, biochemical, and antioxidant properties of wheat lines in the form of split plots in a randomized complete block design with three replications. The results showed that the water stress in the spike stage of wheat lines had significant effects on the studied traits, and there were genetic differences between the lines in terms of the studied traits except for carotenoid and soluble carbohydrates content. Water deficit stress significantly reduced grain yield (24.8%), and among the studied lines, line 5 had the highest grain yield. Lines 2, 5, and 8 showed the highest chlorophyll a, and b content under stress conditions. Increased malondialdehyde (MDA) and total protein accumulation in leaves of wheat lines were observed during water deficit stress, which was accompanied by increased antioxidant enzymes superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) activity, and the highest activity of antioxidant enzymes was observed in line 9. Also, potassium (K), calcium (Ca) and magnesium (Mg) uptake by wheat lines decreased in water deficit conditions, and there was a difference between wheat lines in terms of the amount of these elements uptake under stress conditions. In general, a decrease in chlorophyll content and nutrient uptake under water deficit stress can lead to loss of grain yield, and wheat lines can increase their tolerance to stress conditions by increasing antioxidant activity and reducing MDA accumulation Introduction:Water deficit is a major abiotic stress that severely restricts wheat productivity, particularly during reproductive growth stages such as heading. Drought stress disrupts photosynthesis, accelerates oxidative damage, limits nutrient uptake, and ultimately reduces grain yield. Genetic variability among wheat genotypes provides an opportunity to identify drought-tolerant lines based on physiological and biochemical responses, which is essential for sustainable wheat production under water-limited environments. Materials and Methods:A two-year field experiment was conducted using a randomized complete block design with three replications to evaluate ten wheat genotypes under two irrigation regimes, including normal irrigation and water deficit imposed at the heading stage. Grain yield, photosynthetic pigments, soluble carbohydrates, malondialdehyde content, total protein concentration, antioxidant enzyme activities, and mineral nutrient contents were determined using standard analytical methods. Statistical analyses were performed to assess treatment and genotype effects. Results and Discussion:Water deficit significantly reduced grain yield, chlorophyll a and b, carotenoid content, and mineral nutrient accumulation, while it increased malondialdehyde concentration, soluble carbohydrates, total protein, and antioxidant enzyme activities. Genotypes differed markedly in their responses to drought stress, indicating substantial genetic variability. Higher antioxidant enzyme activities and lower membrane lipid peroxidation were associated with improved drought tolerance. Certain genotypes maintained relatively higher photosynthetic pigment levels and grain yield under stress, reflecting more efficient physiological adjustment and oxidative stress mitigation. Conclusion:Water deficit at the heading stage imposed pronounced effects on yield and stress-related traits in wheat. Enhanced antioxidant defense capacity, maintenance of photosynthetic pigments, and improved metabolic regulation contributed to drought tolerance. The identified superior genotypes represent valuable genetic resources for breeding programs aimed at improving wheat performance under drought-prone conditions.
To investigate the effects of foliar spraying with chitosan and inoculation with mycorrhizal fungi on the growth, morphological characteristics, and essential oil production of Mentha spicata L. (Lamiaceae) under organic farming conditions, a field experiment was conducted during two crop years 2018-2019 and 2019-2020at the organic farm located on the Research and Education field of I.A.U., Karaj Branch (Mehrdasht), Iran. The experimental treatments were arranged in a factorial design with a randomized complete block design (RCBD) and four replications. The experimental treatments included factor A: foliar spraying (control, water spraying, and chitosan foliar spraying at two levels of 2000 and 4000 ppm) and inoculation (with mycorrhizal fungus and without inoculation). The results of the experimental treatments in this study on the growth and morphological characteristics of the mint plant showed that the interaction effect of mycorrhizal inoculum × chitosan foliar-spraying on some features, such as chlorophyll (in particular chlorophyll a), the fresh plant weight, phosphorus concentration, colonization, and essential oil yield per area, was significant. The use of mycorrhizal fungi, combined with foliar spraying of chitosan, can enhance the growth and morphological traits of mint plants. This combination promotes phosphorus acquisition, increases fresh plant weight, and boosts essential oil yield by improving root growth. Consequently, it further enhances both the quantitative and qualitative yield of the mint plant. Finally, it can be concluded that the foliar application of chitosan and the soil application of mycorrhizal fungi, due to the non-use of chemical fertilizers in an organic farming system, can lead to the health of agricultural products, soil, and the environment. Introduction:Wild mint (Mentha spicata L.) is a perennial aromatic plant of the Lamiaceae family with high economic and medicinal value, widely studied for improving growth and essential oil yield under organic systems. Due to increasing concerns about chemical inputs, biopolymers such as chitosan and beneficial microorganisms like mycorrhizal fungi have gained attention as sustainable alternatives. Chitosan is a biodegradable, non-toxic biopolymer derived from crustacean shells and is known for its growth-promoting effects. This study aimed to evaluate the effects of foliar application of Chitosan Plus in combination with mycorrhizal symbiosis on the growth, morphological traits, nutrient uptake, and essential oil production of wild mint under organic farming conditions. Materials and Methods:The experiment was conducted over two consecutive growing seasons (2019–2020 and 2020–2021) at the organic research farm of Islamic Azad University, Karaj Branch. A factorial experiment based on a randomized complete block design was used with two factors: foliar application (control, water spray, 2000 ppm chitosan, and 4000 ppm chitosan) and mycorrhizal inoculation (with and without inoculation), with four replications. Growth and morphological traits, including branch number, inflorescence number, plant height, canopy diameter, fresh and dry biomass, chlorophyll content, phosphorus concentration, and essential oil yield, were measured. Results and Discussion:Analysis of variance indicated significant effects of mycorrhiza, foliar application, year, and some interactions on chlorophyll content, growth traits, biomass, phosphorus uptake, and essential oil yield. Mycorrhizal inoculation generally enhanced branch number, biomass, phosphorus absorption, and overall plant performance, particularly in the first year. Chitosan foliar application significantly increased chlorophyll b content, essential oil percentage, and yield. Interaction effects showed that combined application of mycorrhiza and chitosan improved leaf fresh weight and essential oil traits. Overall performance and trait values were higher in the second year than in the first, indicating cumulative or environmental effects. Conclusion:Combined application of mycorrhizal fungi and chitosan foliar spray improved growth, nutrient uptake, and essential oil characteristics of wild mint under organic conditions. The treatment of mycorrhiza combined with water foliar application was the most cost-effective for improving morphological traits, while mycorrhiza with 4000 mg L⁻¹ chitosan maximized yield. For physiological traits, 4000 mg L⁻¹ chitosan without mycorrhiza enhanced essential oil quality and antioxidant capacity. These findings support the use of mycorrhiza and chitosan as sustainable alternatives to chemical fertilizers in organic mint production.
An experiment was conducted to investigate the physiological responses of wheat to nano-fertilizers under drought stress, using a split-plot design based on a randomized complete block design with four replications at the experimental field of the Faculty of Agriculture, University of Wasit, Iraq, during the 2023-2024 cropping season. The treatments consisted of drought stress at three levels (50%, 70%, and 100% of field capacity) and seed priming with nano-fertilizers at five levels (nano-chelated potassium, nano-chelated iron, nano-chelated zinc, a combination of nano-fertilizers [nano-chelated potassium + iron + zinc], and control [no priming]). The results demonstrated that seed priming with the combined nano-fertilizers improved physiological traits and mitigated drought stress across all stress levels. Antioxidant Enzymes: Compared to the control, priming with the combined nano-fertilizers, nano-zinc, nano-iron, and nano-potassium increased peroxidase activity by 47%, 19.69%, 30.26%, and 35.36%, catalase activity by 31.57%, 29.34%, 18.75%, and 30.85%, and ascorbate peroxidase activity by 44.44%, 37.5%, 28.57%, and 40.76%, respectively. Relative Water Content (RWC): Under 50% field capacity stress, nano-potassium application increased leaf RWC by 33.5% compared to the control. Chlorophyll a, Proline, and Grain Yield: At 50% field capacity, priming with the combined nano-fertilizers, nano-zinc, nano-iron, and nano-potassium increased chlorophyll a content by 35.75%, 10.85%, 3.36%, and 36%, proline content by 39.8%, 23.95%, 18.37%, and 38.21%, and grain yield by 31.39%, 23.15%, 7.61%, and 28.25%, respectively, compared to the control. Conclusion: Seed priming with the combined nano-fertilizers (nano-chelated potassium + iron + zinc) under 50% field capacity stress was the most effective treatment, enhancing photosynthetic pigments, proline synthesis, and antioxidant enzyme activities, thereby reducing drought stress effects and improving wheat grain yield.
