Journal of Plant Process and Function

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Phycobilins, as open-chain tetrapyrrole pigment molecules, serve as accessory photosynthetic light-harvesting pigments in red algae and cyanobacteria. Phycobilin pigments are covalently linked with proteins which form phycobiliproteins organized into large macromolecular complexes called phycobilisomes on the top of the thylakoid membranes. In deep water, only green light is available, thus phycobilisomes are able to absorb this part of light very efficiently and allowing cyanobacteria to survive. Cyanobacteria are capable of adjusting the quantitative pigment composition of phycobilisomes in response to changes in environmental conditions. Phycocyanin is a kind of phycobiliproteins which is characterized by an intense blue color and has been widely used as most important natural dye and antioxidant. The free radical scavenging properties of cyanobacterial phycocyanin are well documented. Phycocyanin eliminates reactive oxygen and nitrogen species and therefore prevents oxidative stress that leads to major damage in the structure of biomolecules of the cell. The variety of applications, from its involvement in the prevention of free radical-related diseases including cancer and Alzheimer's, to its antimicrobial effects, from its use in research laboratories and industry to its significant financial turnover, highlights the importance of reviewing studies on phycocyanin. Hence, this review describes recent findings about the sources, structure, function, production, extraction techniques and different applications of phycocyanin.

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Oxidative stress which is caused by overproduction of free radicals or oxygenated radical species, plays a major role in causing many diseases. The findings suggest the use of antioxidants as compounds to control the release of these radicals or directly prevention of their formation. Therefore, antioxidants can be used as drugs to reduce or prevent oxidative stress. Herbal medicines are the basis of modern pharmacy and many antioxidant compounds are derived from plant extracts. Due to the extinction danger of medicinal plants, the industrial production of many plant antioxidants is not possible. As a result, introducing endophytic fungi as a new source of natural antioxidant compounds could be a new way to access and produce natural antioxidants in food and pharmaceutical industries. In this review, the potential of endophytic fungi to produce phenolic compounds with antioxidant activities was investigated. Most endophytic fungi with antioxidant properties belong to the genera Fusarium and Aspergillus. We hope this review provides useful information for readers to understand the potential of endophytic fungi in the production of new antioxidants, and to encourage scientists to undertake projects that may lead to the development of novel natural antioxidant drugs.  

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In recent years, the number of reports of nanoparticle production using green methods has increased exponentially. Green methods of nanoparticle production are based on oxidation and reduction reactions in which metal ions are reduced to nanoparticles with the help of compounds in living organisms or their extracts, including antioxidants. The presence of biomolecules, including antioxidants in plant extracts in a reducing and stabilizing role, can help produce metal nanoparticles. In living cells, free radicals are produced during the cellular oxidation process. Free radicals are highly reactive due to the presence of a single electron, and are therefore highly toxic to the cell. Antioxidants (natural and synthetic) are compounds that prevent free radicals from damaging the cell, and their presence is essential for living organisms. Green nanoparticles produced with plant extracts, in addition to greater stability and better size than nanoparticles produced using other living organisms, also have improved biological properties. The antioxidant property of the extract is an important parameter to control the green synthesis of metal nanoparticles. The antioxidant properties of plant extracts can lead to a better selection of plant extracts for the synthesis of nanoparticles with desired properties. Plant antioxidants have reducing properties and can be purified and used for the production of green metal nanoparticles.

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Marine algae are known to contain a wide variety of antioxidant compounds. Natural antioxidants, found in many algae, are important bioactive compounds that play an important role against various diseases and aging processes through protection of cells from oxidative damage. At present, there is a global interest in finding new and safe antioxidants from natural sources. Algae can have a variety of primary and secondary metabolites including biosynthesis, metabolism, accumulation and secretion, including carotenoids, phenolic compounds, phycobilins, sulfated compounds, as well as vitamins. All of these compounds are of great value in the medical, pharmaceutical, nutritional, and cosmetic industries. The purpose of this study is to introduce algae as a valuable rich antioxidant natural resource that can be used in various industries.

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Melatonin (N-acetyl-5-methoxytryptamine) is an indole metabolite derived from tryptophan which is synthesized in plant cells in the chloroplasts and mitochondria. Melatonin is present in all plant species, with large variations in its level depending on the plant organ or tissue, and is a molecule endowed with a multitude of functions that makes it worthy to be referred to as a plant growth regulator. One of the main functions of melatonin in plants is its substantial influence on plant hormones such as auxin, gibberellins, cytokinins, and abscisic acid. Melatonin functions in plants are similar to the antioxidant activities of auxin. Melatonin has many beneficial actions, generally improving physiological responses such as seed germination and growth, photosynthesis (pigment content, photorespiration, stomatal conductance, and water economy), seed and fruit yield, osmoregulation, and the regulation of the different metabolic pathways. Its ability to strengthen plants subjected to abiotic stress such as drought, cold, heat, salinity, chemical pollutants, herbicides, and UV radiation makes melatonin an interesting candidate for use as a natural bio-stimulating substance. In addition, melatonin is involved in numerous cellular functions as an antioxidant. It acts as an excellent scavenger of reactive oxygen species (ROS) and reactive nitrogen species (RNS) in plants. The studies showed that melatonin act as a direct antioxidant, neutralizing several ROS/RNS and other radical species harmful to the cell, and also acts as an activator of the antioxidant response, up-regulating various transcription factors that triggers the activity of antioxidant enzymes such as superoxide dismutases, catalases, peroxidases, and those involved in the ascorbate-glutathione cycle. Melatonin also acts as a circadian regulator, cyto-protector, and growth promoter, rhizogenesis, cellular expansion, and stress protection, in plants. All these data lead us to the idea that exogenous melatonin treatment might help crops resist under biotic and abiotic stressful environmental conditions. 

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The production of reactive oxygen species occurs during the natural metabolism of oxidative-breathing cells. Among reactive oxygen species, hydrogen peroxide is more dangerous to cell life due to its long half-life, meanwhile it is an important regulatory molecule in redox signaling in living things. Peroxidases are one of the key antioxidant enzymes that are widely distributed in nature and promote the oxidation of various electron donor substrates simultaneously with the decomposition of hydrogen peroxide which lead to production of water during reducing hydrogen peroxide and other hydroperoxides. Meanwhile, peroxidases, in addition to their known peroxide inhibitory properties, have physiological oxidizing functions.Based on the chemistry of the active site in the interaction with the peroxide, peroxidases are classified to non-heme and heme bearing peroxidases. The former contains heme in its catalytic center, and the latter has a reactive selenol or thiol in its active site. Iron-based plant peroxidases are divided into three classes I, II and III. Thiol plant peroxidases include glutathione peroxidase and proxy reduxins. The present article explains the structural and metabolic, and properties of peroxidases and provides certain practical procedures for determination of their enzymatic activities.

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Abstract: In this experiment, the response of canola cultivars to salnity stress in germination stage was evaluated using a factorial experiment with four replications in completely randomized design. Six canola cultivars (Fornex, Alice, Orient, Consoul, Okamer and Okapi) were subjected to four salinity levels (0, 40, 80 and 120 mMol NaCl) under room, greenhouse, field? Salinity reduced the percentage of seed germination, seedling vigor index, α-amylase activity and seedling fresh weight, but it increased the mean germination time, malondialdehyde concentration, and cell membrane leakage. At the highest salinity level, Orient and Fornex cultivars had the highest germination percentage (84% and 80%), α-amylase activity (9.3 nmol seed-1 min-2 and 9.4 nmol seed-1 min-2) and seedling fresh weight (0.95 mg and 0.70 gr) compared to other cultivars. The electrical leakage of the seedling was lowest in the latter cultivars. Results showed a positive correlation of canola seedling weight with α amylase activity but negative correlations with the malondialdehyde concentration and cell membrane leakage. Salinity stress increased cell membrane damage and decreased α amylase activity, canola seed germination and seedling growth. Results indicated that under salt stress condition, Okamer and Okapi was sensitive canola cultivars compare with other cultivars.

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Abstract: Jasmonic acid and its methyl ester, methyl jasmonate (MeJA), are naturally occurring plant growth regulators, which can affect many physiological and biochemical processes in plants. In present investigation, the effects of methyl jasmonate (0, 1, 10, 100 and 500µM) on some physiological and antioxidative responses in soybean (Glycine max L.) plants were studied. Under MeJA (1 and 10 µM) treatments, shoot dry weight and chlorophyll content increased and lipid peroxidation decreased. Treatment of plants with methyl jasmonate, especially at 100 and 500 µM concentrations reduced shoot dry weight and total chlorophyll content and increased lipid peroxidation. All concentrations of MeJA increased the activity of superoxide dismutase (SOD), ascorbate peroxidase (APX), catalase (CAT) and peroxidase (POD) and also increased the content of ascorbate pool, phenolic compound and anthocyanins as well. Based on our results, it seemed that the application of methyl assonate at low concentrations enhanced the antioxidant defence system, at the same time, decreased lipid peroxidation and improved growth parameter. The higher concentrations of methyl jasmonate increased lipid peroxidation and reduced plants growth, so that increasing the antioxidant capacity of plants did not decrease the oxidative stress and did not improve plants growth.

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Abstract: Wheat grain yield is reduced by post-anthesis drought stress conditions in most wheat growing farmlands of Iran. To evaluate the effect of post-anthesis-withholding irrigation on yield, yield components and canopy temperature of wheat cultivars, a field experiment was conducted as split plot in a completely randomized block design with four replications at experimental farm of college of Agriculture, Shiraz University during 2009-2010 and 2010-2011 growing seasons. Irrigation regimes (normal and cut off after anthesis) and bread wheat cultivars (40 cultivars) were assigned in main plots and subplots, respectively. The results showed that post-anthesis withholding irrigation significantly reduced grain yield, grain number per unit area, 1000 grain weight, biological yield, harvest index, canopy temperature depression (CTD) index, rate of biological yield accumulation, grain yield production rate and grain filling rate. Maximum grain yield under normal irrigation conditions belonged to Shiroudi (8864 kg.ha-1), Navid (8440kg.ha-1) and Karaj-2 (8403 kg.ha-1) cultivars, whereas in the late season drought stress conditions, Moghan-2 (4445 kg.ha-1) and Adl (4179 kg.ha-1) had maximum grain yield. Positive and significant correlation between grain yield and CTD under two irrigation regimes suggested that CTD might be a good indicator for selecting of drought resistant cultivars for late season water deficit, as well as high grain yield under normal irrigation conditions.

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Abstract: Two experiments were conducted to study the impact of salt stress and salicylic acid (SA) on seed germination and plant growth of maize (SC704) under field conditions in the city of Kerman in 2010. For germination experiment, SA seed pretreatments included control, water soaked, SA soaked in 0.1 and 0.2 mM for 24 hours and salt treatment included control, 40 and 80 mM NaCl. All seed germination parameters including germination percentage, mean germination time, germination uniformity, radicle and root length and seedling dry weight were adversely affected by salt stress. SA especially at 0.1 mM improved all parameters significantly, especially under salt treatment. Under field conditions (40 mM salinity), 0.1 mM SA improved chlorophyll, relative water content, membrane permeability, fresh and dry weight of forage, comb length, grain yield, 1000 seed weight, water use efficiency and K+ in leaf. However, leaf Na+ content was significantly lower when SA was used. Thus, it was concluded that seed pretreatment with SA could be used commercially to improve plant performance and yield in maize under salt stress conditions.

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Abstract: In this study, a greenhouse study was conducted to investigate the growth of Aloe vera with different content of nitrogen fertilizers. Treatments consisted of 0, 0.15, 0.29, 0.43, 0.57 and 0.71 g/pot ammonium nitrate and 0, 0.11, 0.22, 0.33, 0.43, 0.53 g/pot urea. Then the effects of nitrogen fertilizers on fresh weight, photosynthetic pigments and proline content were studied. The results indicated that fresh weight was increased in response to application of 0.29, 0.43 and 0.57 g/pot ammonium nitrate and 0.22 urea as compared to the control. Chlorophyll a content was increased at rate of 0.29 g ammonium nitrate/pot. Chlorophyll b and carotenoid contents were increased at rate of 0.15, 0.29, 0.43 and 0.57 g ammonium nitrate/pot. Chlorophyll a and b contents did not show any differences in response to application of urea, but carotenoid content increased at rate of 0.53 g urea/pot as compared to the control and 0.11 g urea/pot. Proline content was same as control under ammonium nitrate, but increased with urea, significantly. It was calculated that 300 kg/ha ammonium nitrate and 200 kg/ha urea were sufficient for optimum growth and leaf production of A. vera seedlings. These amounts with respect to nitrogen percentages of ammonium nitrate (35%) and urea (46%) are approximately equal to 100 kg/ha nitrogen.

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Abstract: Olive (Olea europaea L.) is an evergreen tree traditionally cultivated in the Mediterranean area, resistant to some degree to salinity and drought conditions. However, olive trees are not so resistant to low temperatures. In recent years, because of high demands for olive oil and fruit, the cultivation of olive trees has been increased in Iran. Different cultivars of olives have diverse reactions to cold stress and so, the selection of cold resistant cultivars is the most effective method to avoid frost damages. In order to compare the impact of cold stress on the content of total protein, lipid peroxidation and photosynthetic pigments, 1-years old olive cultivars of Sevillana and Frantoio, were exposed to low temperatures of 10, 5, 0, -5, -10, -15, -20 and control 20 °C for 12 h. The results indicated that the both examined cultivars were resistant to 0 °C temperature with no significant damages. The photosynthetic pigments of Frantoio did not change even in -15 °C and malondialdehyde levels slightly increased compared with the control (20 °C). Total protein content in Frantoio showed significant decrease from -10 °C, while in Sevillana cultivar there was significant decline of total protein content from -5 °C. Therefore, it can be concluded that Frantoio is more resistant to cold stress than Sevillana.

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Abstract: Enhanced leaf proline, soluble sugar and soluble protein contents with sever salinity stress can improve stomatal conductance and Relative water content. This can inhibit dry matter depletion due to salinity stress, so can be used for screening of safflower cultivars under salinity stress. To evaluate the changes in leaf proline, soluble sugars, glycinebetaine and protein content of six spring safflower under salinity stress, a pot experiment was conducted as factorial base on completely randomized design with three replications in summer 2011 in Yasouj University. The first factor included of four salinity levels as zero, 75, 150 and 225 mM. Second factor included of six safflower cultivars, as Local Isfahan, Spinned Sina, Isfahan 14, Goldasht, Padideh and Sina 411. Traits such as leaf Proline, glycinebetaine, soluble sugars and soluble protein content and leaf relative water content were measured. Interaction of salinity and cultivar was significant for all measured traits. Salinity stress significantly increased leaf proline and soluble sugar content. Relative water content decreased significantly by salinity, so that maximum of it (91.03%) was seen in Padide at control. Sina 411 due to having more leaf soluble sugar and RWC at 225 mM salinity level and Goldasht due to having more proline and glycinebetaine content was more tolerance cultivars than the others, and Esfahan14 that had the least soluble sugar, Relative water content and glycinebetaine content introduced as less tolerant cultivar.

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1Department of Ecology, International Center for Science, High Technology & Environmental Sciences, Kerman, Iran *Corresponding author: oloumi.ha@gmail.com Abstract: Regarding to excess entry of heavy metals to the natural resources and the importance of heavy metals removal from the environment, in this investigation, the effect of some organic acid treatment on cadmium and lead absorption was studied on one week Brassica napus seedlings. Canola seeds were cultured in Petri dishes containing 10 mL of 100 μM CdCl2 or 100 μM PbCl2 and some organic carboxylic acids including 50 μM citrate, 1 μM oxalate, 50 μM fumarate or 300 μM histidine. To study the role of these organic acids on abbreviation of heavy metal stress, some biochemical and growth parameters including the content of total chlorophyll, carotenoids, hydrogen peroxide, malondialdehyde and dry weight, was also investigated in 7 days canola seedlings under Cd and Pb stress. Although organic carboxylic acid treatment increased Cd and Pb absorption by canola seedlings, there was also an increase in content of total chlorophyll, carotenoids and dry weigh in seedlings treated by carboxylic acids. Cadmium and lead stress caused the higher content of hydrogen peroxide but carboxylic acid application decreased the content of malondialdehyde and hydrogen peroxide in seedlings under heavy metals stress. Based on the results, it seems that the application of some organic carboxylic acids not only improve remediation capability of Cd and Pb by canola seedlings, but also has positive effects on abbreviation of Cd and Pb toxicity in canola seedlings.

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1 Department of agronomy and plant breeding, College of Agricultural, Isfahan University of Techchnology, Iran *Corresponding Author: Abstract: The effects of salt stress on the activity of ascorbate peroxidase (APX), glutathione reductase (GR), superoxide dismutase (SOD) enzymes, carotenoid content, the rate of lipid peroxidation (LP) in term of thiobarbituric acid-reactive substances (TBARS) content and grain yield were investigated. Eighteen triticale lines comprising 9 doubled haploid (DH) lines and 9 their corresponding F8 lines as well as two bread wheat cultivars ('Roshan' as a drought tolerant and 'Kavir' as a salt tolerant cultivar), were used. A randomized complete block design with three replications was used for each environmental condition (non-stressed and salt-stressed conditions) at the Research Farm of College of Agriculture, Isfahan University of Technology in a silty clay loam soil in 2008-2009. Both salt stressed and non-stressed experiments were irrigated with water having EC of 1 dS m-1 until mid-jointing stage (43 growth stage of Zadoks scale), and afterward salt-stressed experiment was irrigated with saline water containing 175 mM NaCl and EC= 16 dS m-1. Salinity led to an increase in the enzymes activities and LP and decrease in carotenoid content in the leaves of both triticale and wheat genotypes. An inverse and significant relationship between grain yield loss due to salinity stress with carotenoid content was observed under salinity stress (r = -0.54*). Under both conditions, negative and significant correlations (r = -0.61**) were observed between grain yield and LP. The orthogonal comparison between triticale line and wheat cultivars revealed the superiority of triticale lines for the production of antioxidants and less LP in triticale than wheat under both environmental conditions, which may be related to the development of relatively higher salt tolerant in triticale.

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1Department of Biology, Faculty of Science Shahid Bahonar University of Kerman, Iran *Corresponding Author: Abstract: We investigated the effect of jasmonate on plastidial terpenoids on Cannabis sativa at vegetative stage. We used jasmonate solutions with 0, 1, 5, 10 and 100 µM concentration for treating of plants. Plant treated with Jasmonate showed an increase in chlorophyll a content in comparison with control plants. However chlorophyll b content only increased in 5 µM jasmonate treatment. Also carotenoid content increased in all treated plants but there was no significant difference between various concentrations of jasmonate. The amount of α-tocopherol enhanced in plants treated with 10 and 100 µM jasmonate. Treatment with 1 and 5 µM jasmonate caused a considerable increase in tetrahydrocannabinol. 5 µM jasmonate solutions were more effective in this regards. Cannabidiol content decreased in all plants treated with jasmonate. These results showed that jasmonate encourage the accumulation of primary and secondary isoprenoids in chloroplasts.

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Abstract: Salinity is one of the most important factors that limit plant growth and production in the whole word. Compounds, which are able to reduce the damaging effects of various stresses such as salinity, should be of great important. In this investigation, the effects of spermidine on salt tolerance of Matricaria recutitaa were investigated. The results showed that, salt stress in chamomile plants caused the reduction of growth and increased the amounts of hydrogen peroxide, malondialdehyde and the activity of ascorbate peroxidase and guaiacol peroxidase. Pre-treatment of chamomile plants with spermimdine had no significant effect on shoot growth and the activity of ascorbate peroxidase enzyme, while reduced the content of hydrogen peroxide and malondialdehyde obviously, and increased the root growth and activity of guaiacol peroxidase significantly. Application of spermidine with methylene blue reduced the effect of spermidine on the increment of root growth, decrease of hydrogen peroxide, malondialdehyd and ascorbate peroxidase activity while had no significant effect on shoot growth and guaiacol peroxidase activity. Therefore, it seems that Spd effects on these physiological parameters are through nitric oxide and guanylate cyclase pathway however, more studies required for detail investigations.. .

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* 1 Department of agronomy and plant breeding, College of Agricultural, University of Guilan, Guilan, Iran *Corresponding Author: smrehteshami@yahoo.com Abstract: In order to evaluate the effect of Pseuodomonas different strains on nutrients uptake efficacy and rice yield, an experiment was arranged in Rice Researches Institute of Guilan Province (Rasht) during 2009. The experiment design consisted of four randomized complete blocks in a factorial arrangement. In this research, two factors were evaluated: first, two cultivars (Khazar and Hashemi) and second, eight levels of seed inoculation with PGPB strains (168, 93, 177, 136, 103, 169, 4 and control (without inoculation)). Investigated characteristics consisted of: nitrogen consumption efficacy, phosphorus consumption efficacy, potassium consumption efficacy, phosphorus harvest index, apparent recovery efficacy of nitrogen and phosphorus, physiological efficavy of nitrogen and phosphorus, agronomic efficacy of nitrogen and phosphorus, yield and yield components (number of seed per panicle, number of panicle per panicle and 1000-seed weight). In this experiment, effect of bacteria were significant in the most of studied characteristics. The results of experiment showed that inoculation with bacterial strains had a significant effect on rice cultivars, so Khazar had better response on the most of studied characteristics in compared with Hashemi. Between bacterial different strains, seed inoculation with 168 strain in compared with other strains increased evaluated characteristics significantly. The findings of this research showed that PGPB can interact positively in promoting plant growth, As well as nutrients uptake of rice plants in soil especially P and too, increase the solubility of ions through increased enzymes activity and production of growth hormones that consequently, leading to improved yield.