Journal of Plant Process and Function

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To investigate the effect of salicylic acid (0, 50 and 100 mM) on some physiological characteristics of henna, medicinal-industrial plant, under drought stress (0, -2 and -4 bar induced by PEG 6000) a factorial experiment based on completely randomized design was carried out in the research greenhouse of agriculture faculty of Shahid Bahonar University of Kerman. The content of photosynthetic pigment, protein, antioxidant activity of catalase and poly phenol oxidase and dry matter production were measured as some physiological response of henna. All measured traits affected significantly by drought stress (p<0.01). The highest amount of these traits except the activity of catalase and poly phenol oxidase were recorded for non-stress condition. The only trait that was not affected by salicylic acid significantly was the activity of poly phenol oxidase. The application of 50 mM salicylic acid led to the highest amount of these traits. The interaction of salicylic acid * drought stress was significant only for chlorophyll a, total chlorophyll, protein content, catalase activity and dry matter. Based on the obtained results, it can be concluded that application of salicylic acid on henna could largely improve the deleterious effects of drought stress through modification of physiological responses.

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An experiment was carried out to evaluate the effect of various concentrations of Mg (0, 1, 2, 3 and 4 mM) in the nutrient solution and shading (0 and 50%) on growth, yield, fruit quality and physiological properties in hydroponically grown cucumber (Cucumis sativus L. cv. Nagen 792). With increased Mg concentration in both shaded and unshaded plants, the total plant leaf area and dry weight of leaves increased, whereas specific leaf weight decreased. The highest yield in terms of fruit weight and number per plant in both shaded and unshaded plants were obtained in 3 mM Mg treatment; however yield in shaded plants was 57% that of in unshaded plants. Increased Mg concentration drastically increased Mg content and reduced K and Ca content in the leaves and fruits, particular in shaded plants. Leaf and fruit concentration of Mg increased drastically while K and Ca decreased with increasing Mg in the nutrient solution. The activity of ascorbate peroxidase (APX) and peroxidase (POX) in the leaves was decreased by increasing of Mg concentration. The highest activity of APX and POX was observed in Mg deficiency plants and it becomes more pronounced in unshaded plants. Leaf soluble sugars and starch content were decreased with increasing Mg concentration in the solution, especially in shaded plants. Low Mg concentration in the nutrient solution significantly increased total free amino acids (FAA) in the leaves. In conclusion, Mg requirement of cucumber plants likely increases with light intensity. Thus, higher concentration of Mg (3 mM) in the nutrient solution was the most favorable for cucumber plant growth and function grown in hydroponics.

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Drought stress is one of the most important and most common environmental stress that is limited agricultural production. to evaluate the effect of different levels of deficit irrigation on some properties of three varieties of petunia, a factorial experiment in a completely randomized design with four replicationswas conducted in research greenhouse of Ferdowsi University of Mashhad. Examined factors including drought in four levels (100, 80, 60 and 40% of field capacity) and three varieties of petunia (Supercascade, Tango blue and Tango white). Traits were included fresh weight of plant components, total dry weight, stem diameter, spad, antioxidant activity, leaf weight ratio (LWR), leaf area ratio (LAR), Relative Water Loss (RWL), Water Saturation Defficient (WSD) and Leaf Water Content per unit leaf Area (LWCA). The results showed that with increasing drought from control to severe stress (40% FC) Spad increased from 35.4 to 42.6. percentage of antioxidant activity in Tango White and Tango Blue was more than Supercascade. the most leaf fresh weight was in Tango White and in control stress levels (6.08 g) and 80% of field capacity (5.9 g) and the maximum stems fresh weight (9.7g/plant) and flower fresh weight (15.1 g/plant) were seen in Tango White varity and control stress. total dry weight was observed in Tango White and 100% FC. LWR value in Supercascad, Tango Blue and Tango White were 0.283, 0.538 and 0.496 respectively. WSD (72) and RWL (65%) in Supercascade varity and under severe stress (40% FC) with a significant effect was higher than other treatments. Generally the results showed Tango White and Tango Blue varities, in control and also under water stress conditions had more fresh weight, dry weight and antioxidant activity and had WSD and RWL less than Supercascad and so are more resistant.

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Tea is one of the oldest drinks in the world and due to weather condition, season, age and genetic diversity, the compounds of tea are different. In this study, fresh tea shoots, consisting of one apical bud and two adjoining leaves of clones 100, 278, 451 and DN, in three harvest seasons (spring, summer and autumn) were collected from Tea Research Institute of Iran (Lahijan). Seasonal variation of neutralizing the free radicals (DPPH), caffeine, chlorogenic acid, quercetin, catechin and epigallocatechin were assayed using HPLC. The results indicated that antioxidant activity increased from 1^st harvest (spring) to 3^rd harvest (autumn) in 100 and 451 clones, while the activity decreased in 278 and DN clones. Total protein in 100 and DN clones was not significantly different during three harvesting season. These results suggest that the ecological variations in different season are determining factor for the biochemical compounds of tea clones.

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In order to study the effect of water deficit stress and foliar spray of humic acid (HA) on growth, yield and fruit quality of tomato (Lycopersicon pimpinellifolium (L.) Mill), an experiment was carried out in a split plot based on randomized complete block design with three replications in Research filed of university of Zanjan as during 2016. Treatments consisted arrangement of two irrigation levels (starting irrigation at 100 and 80% ETc) and 4 levels of HA (0, 100, 200 and 300 mg.l^-1). The results showed that deficit irrigation significantly decreased growth, yield and leaf relative water content. Foliar application of humic acid improved growth, yield and fruit quality. The highest leaf area, plant length, relative water content, fruit number per plant, fruit weight and yield per plant (59/2 kg) was found with foliar spray of 200 mg.l^-1 HA under irrigation 100% ETc. Deficit irrigation significantly increased water use efficiency, total phenol, total soluble solid content, titratable acidity (TA), vitamin C and antioxidants activity. The highest content of lycopene (41.1 mg.g FW^-1) and TA (1.55%) was found under irrigation 100 and 80% ETc treatments, respectively with application of 200 mg.l^-1 HA. The maximum value of water use efficiency (19.51 kg.m^-3) was obtained in 200 mg.l^-1 HA under deficit irrigation treatment. Deficit irrigation 80% ETc with reducing 10.1% of fruit yield saved 20% of water as compared to 100% ETc treatment.  According to the results, fpliar application of 200 mg.l^-1 HA under normal and deficit irrigation can be proposed to improve yield and fruit quality of tomato.
 

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In this study, rapeseed Okapi cultivar was treated under three NaCl levels (0, 50 and 100 mM) and four Zinc oxide nanoparticles (ZnO NPs) concentrations (0, 20, 40 and 80 mgL^-1) at flowering stage. The experiment was performed in a completely randomized design (CRD) in the greenhouse of Biology Department of Urmia University, in 2015. Results showed that NaCl (100 mM) significantly enhanced total phenolic, flavonoids, anthocyanin and phosphorus contents and increased ability to scavenge the DPPH radical scavenging activity. Treatment with ZnO NPs (80 mgL^-1) significantly elevated total phenolic and decreased anthocyanin, phosphorus and zinc contents and seed weight. Foliar application of ZnO NPs ameliorated the negative impacts of NaCl by reduction in phenolic, anthocyanin and phosphorus contents and elevation in seed oil content (20.82%) and seed weight (79.28%) at 50 mM salinity and 20 mgL^-1 of ZnO NPs compared to NaCl (50 mM) alone. In conclusion, foliar application of ZnO NPs at 20 mgL^-1 is recommended to farmers as replacement for fertilizers to alleviate the adverse effects of salinity stress.

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Increasing nitrogen absorption efficiency reduces use of excessive application of N. The effect of rootzone temperature on nitrogen absorption needs clarification. The experiment was conducted to investigate low (15°C, RTZ1), high (35°C, RTZ2) and optimum (25°C, RTZ3) root zone temperatures and nitrogen 52.5 (ND1), 78.75 (ND2) and 105 (ND0) mg∙L^-1 levels on cucumber (Cucumis sativus L.), cv. Super N3, cultured in Johnson nutrient solution. Shoot and root fresh and dry weights, chlorophyll content, maximum photochemical quenching )Fv/Fm(, antioxidant activity, total phenol and nitrate reductase (NR) activity increased with N. Shoot fresh and dry weights, chlorophyll content, total phenol, antioxidant and NR activity was reduced at high and low root zone temperature compared to the optimum temperature. Shoot fresh and dry weights increased in RTZ1 and RTZ2 for the ND2 and ND0 treatments. The SPAD value increased in RZT2 at all nitrogen levels. The highest Fv/Fm occurred at ND0 at all temperature levels. Antioxidant activity increased for the ND0 and ND2 treatments with increasing root zone temperature. Total phenol content increased in ND1 and ND2 at low and high temperatures compared to the optimum temperature, and increased with increasing temperature level in ND0 treatment. The NR activity increased at the high root zone temperature in ND2 and ND0 treatments. The ND0 and ND2 treatments alleviated the root zone temperature effect on cucumber grown in hydroponic culture.
 

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St. John’s wort is a traditional herbal medicine used to treat depression and wound healing. Natural resource dependency and traditional cultivation methods often require months and years of time to reach medicinal plants. Establishing a hairy root suspension culture system can accelerate proliferation on a large scale, improve breeding and protect the species, but optimization and production on a large scale require an increase in the biomass and secondary metabolites of the root. In this study, the effect of different concentrations of myo-inositol (50, 75, 100, 125, 150, 175, 200, 225, 250, and 275 mg / l) were evaluated on biomass, phenol, flavonoid, DPPH activity and secondary metabolites in St. John's wort adventitious root in Agricultural Biotechnology Research Institute-Central Region of Iran. The results showed that 125 and 150 mg L^-1 myo-inositol concentration had the highest dry weight, growth rate and growth ratio. The concentrations of 100 and 250 mg L^-1 myo-inositol have been showed the highest and lowest amount of hypericin and pseudohypercin, respectively. From the viewpoint of production of hyperforin, the treatment with 100 mg L^-1 myo-inositol was highest and the concentration of 125 mg L^-1 had the least effect on the level of hyperforin in St. John's wort adventitious root culture. There was a significant difference between treatments in terms of phenol and flavonoid content, so the concentration of 75 and 225 mg L^-1 and 75 mg L^-1 myo-inositol had the highest amount of phenol and flavonoids. The DPPH activity changes were different between treatments, and the 50 mg L^-1 showed the lowest amount of DPPH activity. However, the DPPH activity was highest in treatment with 75 mg L^-1 myo-inositol concentration. Since the potential for stimulating secondary metabolites varies among cultures, elicitors, conditions for applying different treatments and other parameters, further research is needed to optimize better and more efficient guidelines.

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Plantago sp., as a valuable source of natural antioxidants, has diverse food and pharmaceutical applications. In this study, six different Iranian species of plantago were studied to determine their antioxidant activity as well as their total phenolic, flavonioid, flavonol, chlorophyll, carotenoids, and anthocyanin content. The highest total phenolic content (92.37 mg GAE/g DW) and total flavonoids (57.16 mg QE/g DW) were found in P. major, but the highest total flavonols (46.07mg RE/g FW) and carotenoids (0.13 mg/g DW) were detected in P. cornopus. The least 1,1-diphenyl-2-picrylhydrazy (DPPH) activity (0.66 mg/ml) was found in P. major. Also, total antioxidant capacity was in the following order P. major> P. cornopus> P. subulata> P. lanceolate ≥ P. maritima > P. ovata.  Preliminarily comparison of the Iranian plantago species identified them as good sources of phenolic compounds. Hence, P. major followed by P. cornopus rich in natural antioxidants may be recommended as food supplements and nutraceutical aims.

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Sweet pepper is one of the most important commercial vegetable with short postharvest life and high susceptibility to fungal diseases. This research was conducted based on complete randomized factorial design with two treatments of UV-C radiation (0, 5 and 10 kJ m^-2s^-1) and DPI dipping (0 and 1 µM) with 3 replications on sweet pepper fruits. The effects of these treatments were studied on some attributes changes throughout 28 days at 7ºC. The results showed that carotenoid content reduced during 28 days of storage. Treatment of 5 kJ m^-2s^-1 UV-C and combination of 10 kJ m^-2s^-1 and DPI treatment caused an increase in carotenoid content that generally kept the same values than initial value after 28 days at 7 ºC. After 10 kJ UV-C m^-2 treatment, an important initial stress was found and treated samples conserved antioxidant contents regarding the initial content. In these samples DPI dipping generally reduced the antioxidant capacity on the 28 day.  The medium illumination dose showed the highest total phenolics content and reducing sugar. Combination of 10 kJ UV-C m^-2 illumination and DPI treatment caused conservation of protein content after 28 days at 7 ºC. SOD activity increased on 21^th day of storage in treated samples with 5 kJ m^-2s^-1 UV-C and 1 µM DPI. 10 kJ UV-C m^-2 caused an increase in catalase activity on the last day of storage. Illuminated samples with 5 kJ UV-C m^-2 showed the highest peroxidase activity on 14^th day at 7 ºC. Based on the results, a pretreatment of UV-C radiation and DPI dipping was found as an effective technique for quality preservation of sweet pepper fruits during storage.

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In order to investigate the effect of foliar application of different levels of ethanol and methanol on the biochemical characteristics of Digitalis purpurea L., an experiment was conducted based on a completely randomized design with three replications at the University of Zanjan research greenhouse. The treatments consisted of two levels of ethanol (5 and 10%) and methanol (5 and 10%), along with a control treatment (distilled water). The results showed that the maximum amount of total chlorophyll (1.78 mg/g), total carotenoid (0.10 mg/g), total phenol (15.35 mg/g), total flavonoid (58. 2 mg/g) and antioxidant activity (43.76%) were obtained under a 10% methanol treatment. The highest amounts of proline (4.47 mg), soluble sugar (76.20 mg/g), relative water content (76.02%) and leaf nitrogen (1.61%) were observed under a 10% ethanol treatment. The ion leakage index (15.21%) with foliar application of 10% ethanol and catalase enzyme (1.66 mg/g protein) and peroxidase enzyme (0.34 mg/g protein) activity showed a decrease with foliar application of 10% methanol. According to the results, the application of different levels of hydroalcohols improved the biochemical properties of Digitalis purpurea L.

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In the last two decades, the role of selenium (Se) as an antioxidant has generated a wide interest in it. In trace amounts, Se is an essential micronutrient and has important benefits for animal and human nutrition, although it has not been confirmed to be an essential micronutrient in higher plants. This study evaluated the effects of the application of different concentrations of sodium selenate (0, 5 and 10 µM) in hydroponic culture on the growth and some physiological parameters of two cultivars of tomato. The results showed that selenium at a concentration of 5 caused a significant increase in the growth indicators, including the dry weight of the shoot of the lale and Riogrand cultivars (29.5% and 41.34%, respectively) and the root (in the lale cultivar, 27.5 and 35% in the Riogrand cultivar), chlorophyll a (23.52% in the lale cultivar and 34.34% in the Riogrand cultivar), content of phenolic compounds (2 times in both cultivars), carbohydrate content, glutathione content (2 times in both cultivars), and the activity of glutathione peroxidase enzyme (43.58% in the lale cultivar and 27.27% in the Riogrand cultivar) in comparison to the control plants. However, the concentration of 10 µM selenium caused a significant decrease in these indicators compared to the control. Also, the concentration of 5 decreased  the amount of hydrogen peroxide (H₂O₂), electrolyte leakage and malondialdehyde in both Riogrand and lale cultivars in comparison to the control. We concluded that 5 µM of sodium selenate provides a better growth condition for the two cultivars of tomato by having the highest antioxidant activity (both enzymatic and non-enzymatic) and the least amount of damage to the cell membranes.

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The purpose of this study was to evaluate how various morphological, phytochemical, and morphological traits of Mullein were affected by drought stress. A randomized completely blocks design with four treatments and four replications was used for this study. T1 (100% of field capacity), T2 (80% of field capacity), T3 (60% of field capacity), and T4 (40% of field capacity) were the stress treatments. Plant height, length of inflorescence, number of leaves per plant, flower diameter, flower yield, relative moisture content, proline, chlorophyll a and b, total phenol, flavonoid, and antioxidant activity were the characteristics that were examined. The analysis of variance results indicated that antioxidant activity and leaf number were not significantly affected by drought stress, but other variables were significantly affected (p <0.05). The findings demonstrated that drought stress resulted in a significant increase in proline and total phenol content and a significant decrease in morphological traits, flowers production, relative water content, and chlorophyll a and b. T1 and T4 had the greatest (9.99 mg Q/g DW) and lowest (91.9 mg Q/g DW) total flavonoid contents, respectively. Total phenol contents ranged from 28.1 (mg GAE/g DW) for T4 treatment to 27.47 (mg GAE/g DW) for T1 treatment.