جستجوی مقالات مرتبط با کلیدواژه "آسکوربات پراکسیداز" در نشریات گروه "باغبانی"

In order to investigate the effects of humic acid and mycorrhiza on gerbera cv. Dune, an experiment was performed as a completely randomized design with two factors and three replications in hydroponic conditions. First factor included humic acid at 4 concentrations (0, 500, 1000, and 2000 mg L-1 as media drench). The second factor contained two levels of mycorrhizal fungi (with and without mycorrhiza at root zone). Attributes such as leaf number, rosette diameter, root fresh and dry weight, flower diameter, flower stalk diameter and number, time from bud emergence to anthesis, total phenol content, colonization percent and the activity of ascorbate peroxidase and hydrogen peroxide were measured. The results showed that humic acid and mycorrhizal fungi treatments led to increase in the leaf number, rosette diameter, fresh and dry weight of roots and antioxidant enzymes activity and decreased the time from bud emergence to anthesis comparing untreated plants. Phenol content was significantly increased compared to control plants by application of 1000 and 2000 mg L-1 of humic acid plus mycorrhizal fungi. The combined use of humic acid and mycorrhiza was effective to improve some morphological and physiological properties of gerbera and the concentration of 1000 mg L-1 humic acid plus mycorrhiza application were the most effective treatment.

In order to investigate amount of deficit irrigation and different levels of water salinity on some morphophysiological traits of parsley, an factorial experiment based on completely block design in three replicates was carried in greenhouse condition. The first factor include irrigation amount at three levels (60, 80 and 100% of field capacity) and the second factor include water salinity at three levels (0.5, 2 and 4 dS/m). Results showed that decreasing irrigation and increasing water salinity cause deacreasing plant height, leaf number per plant, aerial fresh and dry weight, root fresh and dry weight, relative water content and chlorophile content. With increasing salinity to 4 dS/m ion leakage and activity of catalase and ascorbate peroxidase increased and with increasing amount of irrigation these traits reduced significantly.

Drought is one of the most important factors limiting plant growth worldwide and the most common environmental stress. In response to environmental stresses, abscisic acid (ABA) plays an important role in initiating and coordinating many physiological and biochemical processes in reducing oxidative stress. To study the effects of abscisic acid on some antioxidant enzymes and proline of Lavendula angustifolia cv. Organic Munestead under deficit irrigation stress, a pot experiment was conducted as factorial based on randomized complete block design with three replications. The treatments were four levels of irrigation regimes (30-40, 50-60, 70-80 and 90-100 percent field capacity (FC)) and ABA including three levels (0, 15 and 30 mM/L). Traits evaluated in flowering stage. The highest level of drought resulted an increasing 91% in proline and decreasing 29.88% in carotenoid compared to control. Abscisic acid had a significant effect on all traits, except of carotenoid content. Abscisic acid 30 mM/L spray and irrigation regimes 30-40 percent FC induced the highest content of CAT, POD and SOD, while the maximum of antioxidant activity (70.54 mg/g DW) has resulted in ABA 15 Mm/L application and irrigation regimes 50-60 percent FC and the maximum of proline (2.51 mg/g DW) has resulted in ABA 15 mM/L application and irrigation regimes 30-40 percent FC. The highest fresh and dry weight of shoot and root were obtained from non-application of ABS in irrigation of 90-100% FC. It is determined abscisic acid application in deficit irrigation stress conditions increased the activity of antioxidant enzymes of lavender to counteract the negative effects of deficit irrigation stress.

In order to study the effects of foliar application of nano iron oxide particles and biofertilizers on root growth, antioxidant enzymes activity in two parts of root and leaf, as well as some other physiological characteristics of black cumin (Nigella sativa L.) a pot experiment with factorial arrangement in randomized complete block design with three replications was carried out in 2017 growing season at the Faculty of Agriculture, University of Shahrood. The first factor was foliar applications of nano iron oxide at three levels (F0= control, F1= 1.5 and F2= 3 g /1 l water) and the second factor was biofertilizers at five levels (B0= Control, B1= Glomus Intraradices, B2= Glomus mosseae, B3= Azospirillum and B4= Azotobacter solution). The results showed that activity of antioxidant enzymes catalase, polyphenol oxidase in two parts of root and leaf was influenced by two factors of biological fertilizers and foliar application of nanoiron oxide particles, so that the use of biofertilizers reduced and with increasing iron oxide concentration, activity they increased. The highest activity of ascorbate peroxidase in leaf was obtained from F2B0 treatment. The interaction effect of foliar application of nanoiron oxide particles and biofertilizers had a significant effect on photosynthetic pigments and aerial dry weight, so that the highest amount of chlorophyll a was obtained from F2B1 treatment, chlorophyll b, aerial dry weight and iron of aerial from F2B2 treatment. According to the results of the experiment, the symbiosis with G. intrarardits fungus caused a significant increase in the absorption of nitrogen and iron elements in the plant.

Recently, environmentally-friendly materials, ideally those able to be obtained from bio-based resources and presenting biodegradable characteristics, are used to improve quality and biosafety of horticultural products. Fruits of sweet cherry (Prunus avium ‘Siah Mashhad᾽) were coated by galbanum gum (0, 1, 2, and 3%w/v), cumin essential oil (0, 100, and 200 µL L-1), and calcium chloride (0 and 1%w/v). The coated fruits were then kept in a storage at 2±1°C with 90-95% relative humidity for 30 days and one additional day at 20ºC. After that, the quality of fruits was evaluated. All concentrations of experiment factors, increased the activity of catalase and peroxidase enzymes 15 days after storage and retained these properties until storage. Also these treatments slowed the rapid reduction in ascorbat-peroxidase enzyme activity, acid ascorbic content and general acceptance. 1 and 2%w/v gum galbanum composed with 1%w/v calcium chloride/200 µL L-1 cumin essential oil cause a temporary increase in total antioxidant and phenol 15 days after storage and retained these features until the end of the shelf life. 1%w/v galbanum gum combination with 1%w/v calcium chloride/ 200 µL L-1 cumin essential oil can be used as a suitable alternative for chemicals in maintaining sweet cherry quality and shelf ilfe.

In this study the effect of spermidine on proline, soluble sugars, peroxidase, ascorbate peroxidase, membrane stability and chlorophyll a and b, under irrigation period were evaluated. This study was conducted in pots and as a factorial completely randomized design in four replications. Espermidine was applied at 0, 1 and 2 mM and irrigation period was imposed at three days, five days and seven days in between. The Results showed irrigation period in seven days compared to control group increases proline content, activity of peroxidase and ascorbate peroxidase and membrane stability, and decrease in soluble sugars, chlorophyll a and b. The plants that have been irrigated for seven days, treatment with 2mM spermidine (relative to concentrations of 0 and 1 mM) increased proline content, soluble sugars, activity of peroxidase and ascorbate peroxidase at the highest level (class a). The membrane stability in these plants the concentration of 0 mM spermidine was highest (77.75%). Spermidine had no significant effect on chlorophyll a and b. Generally treatments with 2 mM spermidin in plants that were irrigated for seven days Increased proline content (1.11 mM/g.FW), soluble sugars (0.96 mg/gFW), peroxidase activity (0.91 OD.g-1.FW.min-1) and ascorbate peroxidase activity (0.98 OD.g-1.FW.min-1) at the highest level (class a).

Nowadays, horticultural products especially in our country are damaged by the climate change events (rising temperatures, water shortage associated by drought and extreme temperature fluctuations). The greatest economic damage to horticultural crops are caused by winter chilling and / or spring frosts, in which has been increased by seventimes during the last 10 years. Indeed, just during 9 months of 2016-2017 year, the chilling/frost damages were reached to 140 million euro of the total damage value of 240 million euro to agriculture (about 60%). According to the Agricultural Insurance Fund, maximum amount of compensation to farmers of the country was paid to apples, walnuts, grapes, almonds, pomegranates, oranges and pistachios orchardists, respectively. Grape (Vitisvinifera), a member of the Vitaceae family, is the most important horticultural crop in Takestan region, ranking top in producing raisins in Iran. Yearly, horticultural practices in order to reduce the severity of chilling damages to crops cost a lot under orchard conditions. Some of these practices are included burying vines under soil, winter ice-watering, flood irrigation, and turning the heaters on. Nowadays, cheap and fast alternative methods such as anti-freezes spraying havebeen considered to reduce the freeze injuries under orchards. These compounds as mechanical barriers either prevent the ice crystals formation on the sensitive plant tissues or activate the freezing tolerance mechanisms in the plants. Salicylic acid (SA), a type of phenolic acid, is one of the most secondary metabolites in the grape. SA not only plays an important role on the determination of the quality, color and taste of fruit, but also influences on the plant responses into environmental stresses such as drought, chilling, salinity and heavy metals. Natural osmolites such as soluble sugars, amino-acids and ammonium compounds are accumulated inside the plants under natural conditions. Commercial anti-freeze/anti-transpiration compounds on the basis of the mentioned natural osmolites are used to increase the freezing tolerance or postponing the bud break of horticultural crops. For example, Bio-bloom, Tiofer®, Cropaid® and Fosnutren® were used as anti-freeze compounds under almond, cherry, pistachio and apple orchards in Iran. The efficiency of this method to reduce the chilling injuries in vineyards is not well known. Therefore, to consider the effects of plant basis anti-freeze compounds on the freezing tolerance of red seedless grape under Takestan climate conditions, the current experimentation was conducted. In this regard, the important freezing tolerance determining osmolites as well as some of the qualitative and quantitative characters of vines in response to these compounds were evaluated.
In order to study the likely increase in grape spring freezing tolerance using the anti-freeze compounds under the orchard, an experiment was conducted as randomized completeblock design (RCBD) with anti-freeze compounds in Agriculture and Natural Resources Research Center of Qazvin during 2012-2013. Minimum monthly temperature during the autumn and winter months was -12.2 °C. The treatments including the spray of SA, Tiofer®, Cropaid®, Bio-Bloom® and water (control) were used on vines during fourphonological stages: before plant dormancy, during bud swelling, start of clustering and during the final clustering on the three red seedless vines per plot. Quantitative and qualitative characters such as cluster weight, yield and total soluble solids (TSS) were measured. Leaves osmolites contents such as proline (Bates et al.,1973) and glycin-betain (Grieve and Grattan.,1983) as well as the status of the freezing resistance index enzymes activities such as Glutathione peroxidase (GPX) (Updhyaya et al.,), Ascorbateperoxidase (APX) (Nakano and Asada,1981) and Catalase (CAT) (Aebi, 1984) were evaluated. All statistical analyses were made using SAS software. The comparison of mean values for the different treatments was made by ANOVA, followed by the Duncan’s test at the significant level of 0.05.
The results showed that the anti-freeze compounds resulted in an significant increase in the TSS, cluster weight and yield by 22%, 17% and 26%, respectively and the most effectswas observed in Bio-bloom. Our results regarding the effect of SA on the TSS was in accordance with other researchers (ShokrollahFaam, 2011; Sedighi et al., 2011; Champa et al., 2014;Marzouk and Kasm, 2011). However the effect of other anti-freeze compounds on the quantitative characteristics has not studied yet. Tiofer and Cropaid had no significant effect on the grape cluster weight. Proline content increased significantly using anti-freeze compounds compared to control during 2012-2013. But there was no significant difference between the different anti-freeze compounds for proline content. The most important content of betaine-glysine was observed in SA and Bio-bloom treatments. A decrease in air temperature during 2013 dormancy period resulted in higher amount of osmolytes contents (betaine glycine) and freezing resistance index enzymes activities compared to those of 2012. The most important contents of these enzymes activities were obtained in SA, Tiofer, Cropaid and Bio-Bloom treatments, respectively and the less important content was observed in control.
According to these results the commercial anti-freeze compounds could be useful not only for an increase in the grape spring freeze resistance but also for an improvement in the grape cluster weight, total soluble solids and yield. Osmolytes contents such as such as proline and betaine glycine and enzymes GPX, APX, CAT are significantly higher in anti-freeze treated plants compared to control. Since high levels of soluble solids, mentioned osmolytes and enzymes resulted in an increase in cold resistance in plant, the use of antifreeze as an easy and inexpensive way to increase the cold hardiness of grapes is recommended. These results were obtained with this antifreeze in 5 ppm concentration. Therefore more researches on the other varieties using different concentrations of anti-freeze compounds are recommended.

Henabne(Hyoscyamus reticulatus L.) is a rich source of tropane alkaloids including hyoscyamine (Hyos) and scopolamine (SCP), widely used in pharmaceutical field. The aim of the present study was to assess the effect of different concentrations (0, 50, 100 and 200 µM) of methyl jasmonate (MeJA) at two different times of exposure (24 and 48 h) on growth, antioxidant enzymes activity, tropane alkaloids content, and the expression level of hyoscyamine-6-beta-hydroxylase (h6h) gene in H. reticulatus hairy root cultures. The results showed that MeJA at high concentration (200 µM) led to the decline of fresh and dry weight of hairy roots. Catalase (CAT), guaiacol peroxidase (GPX) and ascorbate peroxidase (APX) activities were significantly increased by MeJA, especially at 200 µM in elicited hairy roots. As well, CAT and GPX activities, but not of APX, were also affected by exposure time of MeJA. According to the GC/MS analysis, the highest percentage of SCP (13.96%) and Hyos (21.9%) were respectively obtained when hairy roots were exposed to MeJA at concentrations of 100 and 200 µM for 48 and 24 h, which were, respectively, 1.6- and 1.25-fold higher than those in the control roots. According to the results of semi-quantitative RT-PCR analysis, the highest expression of h6h gene (6-fold higher than in the control) was obtained after 24 h exposure to 100 µM MeJA. These results indicate that MeJA, due to stimulation of the expression of key genes involved in the biosynthetic pathway of tropane alkaloids, could be used as an effective elicitor for increased production of Hyos and SCP.

Narcissus is a genus of hardy, spring-blooming, bulbous plants in the family Amaryllidaceae. Numerous studies have demonstrated positive effects of various chemical additives (e.g. biocides, surfactants, ethylene inhibitors, wound healing enzyme inhibitors) on the postharvest, water relations and longevity of cut flowers. Cut flowers can have limited commercial value because of their dehydrating during vase life that decreased water uptake. Petal senescence is part of a developmental continuum in cut flowers and proceeded by tissue differentiation, growth and development of seeds and coordinated by plant hormones. Senescence can be studied at cellular, tissue, organ or organization level as a genetically programmed event. The vase life of cut narcissus flowers is often very short. The development of senescence symptoms is caused by vascular occlusion, which inhibits water supply to the flowers. Petal senescence was marked by the loss of turgor in petal tissue followed by complete wilting. The development of occlusions is thought to be caused by various factors, such as bacteria, air emboli and physiological responses of stems to cutting. However, despite anecdotal evidence of positive effects, improving postharvest water relations of cut flowers by various physical stem-end treatments is little researched.
The Narcissus flowers harvested from Khafr city of Fars province, in February 2015. The Thyme plants harvested in September 2014 and Savory plants harvested in December 2014 and then submitted to hydrodistillation in a Clevenger-type apparatus for 3 hours. This study was carried out in a completely randomized design with 3 replications. The treatments included control (distilled water), two levels of Savory essential oil (50 and 100 ppm) and two levels of Thyme essential oil (100 and 200 ppm). 2% sucrose were added to control and other of treatments . The cut flowers were also kept at temperature of 20±2 ºC with air humidity (RH) of 70±5%. Different parameters including flower weight, uptake of preservative solution, and wilting of flowers were measured every 2 days (0, 2, 4, 6 and 8) and antioxidant enzyme activity (APX) were measured in days of 0, 4 and 8 during storage period, and at the end of experiment, the vase life were measured. The results analyzed by SAS software and drawing tables and diagrams done by Excel software.
The results showed that Savory essential oil 50 ppm treatment was effective in improving the flower weight of cut narcissus by increasing uptake of preservative solution and also reducing wilting of flowers and antioxidant enzyme activities. At 200 ppm of thyme essential oil observed reductionin flower weight and uptake of preservative solution, but increasing in wilting of flowers and antioxidant enzyme activities. At 50 ppm of savory essential oil with average days 12.26, the vase life of cut flowers increased significantly as compared to control (10.36) and at 200 ppm of thyme essential oil treatment with average days 8.53, observed decrease invase life of cut flowers compared to control. Impaired water uptake is typically caused by cut stem occlusions due to microbial, physiological and physical plugging of xylem vessels. Essential oils constituents and derivatives have a long history of application as antimicrobial agents in areas of food preservation and medicinal antimicrobial production. physical treatments damage xylem vessels, allow increase of microbes and increase nutrient supply for microbes, which occlude stems. Recently many works carried out about application essential oils as antimicrobial agents under in vitro and in vivo condition and indicated that essential oils could increase postharvest quality of many horticultural crops such as tomato, table grape and kiwifruit (1, 15 and 24). In addition to improving water uptake, other approaches to maintaining a positive postharvest water balance for cut flowers and foliage include minimizing water loss though reduction in leaf area, keeping them in an environment conducive to less water loss (viz. low temperature and high RH) and providing compatible osmotica (e.g. sucrose) in vase and/or pulsing solutions. The loss of membrane integrity has been shown to cause an increase in the permeability and leakage during senescence in various flowers.
Results of this study showed that savory essential oil treatments increased quality and vase life of narssisus cut flowers compared to control At higher concentrations of thyme (200 ppm) the flowers remained closed, wilted quickly and senesced before controls.

Salt problems are of great concern in arid and semi-arid regions and can severely limit plant growth and yield. Vermicomposts have high porosity, aeration, drainage, and water-holding capacity and contain nutrients in forms readily taken up by plants. This research was conducted to investigate the effect of different rates of vermicompost (0, 100, 200 and 300 g), mixed with farm soil, on catalase (CAT) and ascorbate peroxidase (APX) enzymes and some of the morphological traits of Festuca arundinacea cv Queen, under salinity stress (0, 3, 6 and 12 dS/m) conditions. Results showed that the highest activities of CAT (50.47 Ug/FW) and APX (715.53 Ug/FW) was obtained at NaCl concentrations of 12 dS/m with 300 g vermicompost. The highest values of leaf area (10.41 cm2), shoot length (28 cm) and dry shoot weight (46.07 g) were obtained when plants were grown in soil with 300 g vermicompost. The present findings revealed that salinity (NaCl) and application of vermicompost triggered an antioxidant response in Festuca arundinacea. Therefore, application of vermicompost not only can increase plant growth and anti-oxidant enzymes activity, but also could be an effective solution to reduce the effects of high concentrations of sodium chloride on growth of Festuca arundinacea cv Queen in saline soils.

Some crops have the ability to withstand environmental stresses as they prevent further production of oxygen free radicals or cope with the produced free radicals. Accordingly, in order to investigate the effect of mycorrhizal fungi species on eco-physiological characteristics of Hyssopus officinalis L., a factorial experiment based on randomized complete block design was conducted with three replications at the research farm of west Azarbaijan Agricultural and Natural Resources Research Center in 2012. Treatments were species of mycorrhizal fungi (Glomus mousseae, G. intraradicese, G. fasiculatum, G. claroideum, Acaulospora longula and control without mycorrhiza) and four levels of irrigation (irrigation at 80, 70, 60 and 50% field capacity). Results showed the significant effects of irrigation and mycorrhiza on the ascorbate peroxidase, and significant interaction between irrigation and fungi species on the percentage of mycorrhizal colonization, catalase activity and superoxide dismutase. The order of highest colonization of Hyssop root was G. mosseae, G. intraradices, G. fasiculatum, G. claroideum and A. longula compared to control treatment in all irrigation levels. The highest activity of superoxide dismutase and catalase in plants inoculated with G. mosseae, G. fasiculatum, G. fasiculatum and G. claroideum belonged to irrigation at 50, 60, 50 and 50% of field capacity, respectively. However, the highest ascorbate peroxidase belonged to irrigation at 50% field capacity. In conclusion, the results showed that mycorrhizal species affected the amendment of water deficit stress due to the increased antioxidant enzyme activity in order to neutralize the effects of free radicals and cell membrane stability.

Information about the effect of endophytic fungus Piriformospora indica on wheat response to stress conditions is very limited and sometime contradictory. This greenhouse research was conducted in a hydroponic culture to investigate the inoculation effects of mycorrizhal-like fungus, P. indica, on enzymatic and non–enzymatic defense mechanisms of wheat (Triticum aestivum L., cv. Niknejad) at two levels of phosphorus (P) supply (deficient and sufficient). The experiment was factorial, based on a completely randomized design with three replications. Sixty days after applying the treatments, plants were harvested and shoot dry weight and concentration of P, iron, zinc and activity of antioxidant enzymes like catalase (CAT), ascorbate peroxidase (APX), guaiacol peroxidase (GPX) and chlorophyll a, b and carotenoids contents were measured. Results showed that P-deficiency reduced shoot dry weight and concentration of P and iron and increased concentration of zinc in the shoots. Inoculation of wheat roots with P. indica in P-deficiency condition resulted in significant increasing of shoot dry weight and P concentration. Also, chlorophyll a, b contents and concentration of carotenoids in P-deficiency condition was significantly higher than P-sufficiency condition. Inoculation of P. indica to wheat roots decreased chorophyll a, b contents and concentration of carotenoids. Inoculation of P. indica in P-deficiency condition significantly decreased the activity of GPX and significantly increased the activity of CAT and GPX in P-sufficiency condition. In general, inoculation of fungus P. indica to wheat plant could be recommended as an effective method to alleviate deleterious effects of P-deficiency and increase its tolerance to this stress.

One of the methods employed to enhance plant secondary metabolite production is the use of abiotic elicitors in plants. In this research، the effect of heavy metal nickel as abiotic elicitors was studied on some physiological parameters in Hyoscyamus niger L. to investigate the use of unstressful concentration of this metal in order to increase secondary metabolite synthesis in later researches. This research was carried out in the Department of Biology of Shahid Bahonar University of Kerman in a complete randomized design with three treatments and three replicates. The seeds of Hyoscyamus germinated in germinator under gibberellin treatment and then were transfered to the pots of sand and peat. After 40 days of growth، the plants were treated with 50 and 100 µM nickel in hydroponics condition (nickel amounts were added to nutrient solution). According to the obtained results، photosynthetic pigments reduced under Ni treatment while hydrogen peroxide، lipid peroxidation and antioxidant enzymes activity increased. Investigation of Ni stress on main macromolecules such as protein، membrane lipids and chlorophyll showed that the effects of 50 and 100 µM Ni was same، while the PAL activity and polyphenols synthesis were the second responses of plants to stress obserevd in 100 µM concentrations. Therefore، it seems that the higher concentration of Ni (100 µM) was more effective for the increment of secondary metabolite in this plant.

Evaluation of certain biochemical and physiological changes under stress can provide an appropriate approach for the study of hereditary factors influencing salt stress tolerance. In this greenhouse study، the changes in water status، osmotic regulators and activity of antioxidant enzymes in leaf tissue of panic blue grass (Panicum antidotale Retz) exposed to salinity were evaluated over five consecutive weeks. Five levels of salinity (0، 70، 140، 210 and 280 mM NaCl) were applied at the 4-leaf stage. Results showed that the highest leaf relative water content (RWC) in non-saline (control) treatment، as compared with the lowest RWC in 280 mM salinity treatment، was 8. 67، 31، 25، 28 and 27% in the 1st to the 5th wee، respectively. Average leaf osmotic potential showed a decreasing trend in different salinity treatments over time and was reduced from -0. 717 MP in the first week to -1. 26 MP in the 5th week after exposure to salinity. Total soluble carbohydrates content of the leaves was reduced with increasing the salinity level. After 28 days of exposure to salinity، the activity of ascorbate peroxidase enzyme in non-saline treatment was 40% more than the 280 mM treatment; although the highest activity of ascorbate peroxidase enzyme was observed in the 70 mM treatment. Leaf RWC (r=0. 62**) and membrane stability index (r=0. 52**) had the most positive correlation with dry matter production of blue panic grass. In addition، increasing the DPPH radical scavenging activity (r=-0. 61**) and total phenol concentration (r=-0. 69**) had effective role in survival of this salt-tolerant plant. The data analysis، using stepwise regression، indicated that total phenol concentration (β= -0. 722) and leaf proline concentration (β= -0. 265) were the main components of salinity tolerance of blue panic grass.

Hypericum perforatum L. is a valuable medicinal species. The plant geneus includes 17 species in Iran, but H. perforatum is the only valuable species.The species plays an essential role in the treatment of depression. In this study, Hypericum perforatum was treated with different concentrations of molybdenum including (control, 0.1, 0.4, 0.8, 1.6 µΜ) in Hoagland solution at 6.8 pH and then samples were used to measure biochemical parameters. Molybdenum significantly increased proline content. The shoot catalase and ascorbate peroxidase activities increased in all treatments of molybdenum, but in root, it was reduced in higher concentrations. Shoot peroxidase activities increased by treatments of molybdenum, except at a concentration of 0.8µΜ. The increase in peroxidase activity was also observed in roots but it was reduced at higher concentrations. The malondealdehyde and molybdenum content increased in higher concentrations of molybdenum. Molybdenum content increased by increasing treated molybdenum. Therefore, molybdenum stress increased the proline content and peroxidase, catalase and ascorbate peroxidase activities, and toxicity symptoms were observed in high concentrations of molybdenum as lipid peroxidation. Data were analyzed by SPSS and mean comparisons was performed by Duncan's multiple range test. In each experiment, 3 replications were used.

Ascorbate as a strong antioxidant has a considerable bio effect on growth of plants, such as increase in their tolerance against environment stresses. In this investigation, the effect of salt stress and its interaction with ascorbate on amount of proline, catalase and ascorbate peroxidase enzymes and MDA in a medicinal plant of Cuminum cyminum L. was randomly studied in the green house conditions with three replications. Plants were treated by different concentrations of NaCl (0, 25, 50, 75, 100, 125 mmolar) and ascorbate (9 mmolar). In the plants treated with salt, the amount of proline, antioxidant enzymes activity and MDA were increased with increasing NaCl concentrations. The plants treated with NaCl and ascorbate at the same time in a same NaCl concentration, the amount of proline, catalase activity, ascorbate peroxidase and MDA were increased. The results indicated that the ascorbate was one of the antioxidants that caused an increase in resistance of Cuminum cyminum L. to salt stress.