Research Article
Medicinal Plants
Alireza Moshrefi-Araghi; Seyyed Hossein Nemati; Mahmood Shoor; Majid Azizi; Nasrin Moshtaghi
Abstract
Introduction Mentha is one of the most important genera of aromatic plants which belongs to the Lamiaceae family. The genus of Mentha is distributed across Asia, Africa, Australia, Europe, and North America. Mentha longifolia L., also known as wild mint, is a fast-growing aromatic perennial herb. ...
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Introduction Mentha is one of the most important genera of aromatic plants which belongs to the Lamiaceae family. The genus of Mentha is distributed across Asia, Africa, Australia, Europe, and North America. Mentha longifolia L., also known as wild mint, is a fast-growing aromatic perennial herb. It is widely used as herbal medicine and is beneficial for the immune system and fighting with secondary infections. The essential oil of this plant is partly responsible for the decongestant, antispasmodic and antibiotic effects. Currently, much emphasis is being laid on conserving plant germplasm as valuable bio-resources. Selection between and within accessions for a high level of herbage yield and other characters requires an effective tool to be applied by mint breeders. Achieving to cultivars that are more capable of optimum producing is a breeding goal. The objectives of this study were to analyze the diversion of the agronomical traits of Mentha longifolia L. genotypes from different regions of Iran under a similar condition in order to find the superior genotypes and introduce for the domestication of this plant. Material and MethodThis research was performed at the research field of the Ferdowsi University of Mashhad. The field is located at 36˚15' North latitude and 59˚38' East longitude, at an altitude of 985 meters. The information related to temperature and precipitation was obtained from climate station. Soil sampling was done in the depth of 0.3 meter and physical experiments on samples were done before starting the experiment. The field was fertilized by 25 kg/ha animal manure. Seeds of 20 genotypes of M. longifolia L. were prepared from Gene Bank of Research Institute of Forests and Rangelands and a view of the wild mint genotypes distribution was presented on the map. The experiment was performed in a field with 500m2 areas in 2015-2016 growing seasons. The experiment in form of compound analysis arranged in complete randomized design with three replicates of 20 wildmint's genotypes in every replication. In each furrow, fourteen bush was totally studied, in which the distance between the two plants was 20 cm. The plot was considered 1.2 by 3 m and the distance between rows was 0.50 m. The dimension in the plots for every replication area was 3.6 m2 and the distance between blocks were 1.5 and between experimental units were 0.5 meters. Picking up was done after elimination of 0.5 meters from every side of replication. The essential oil was extracted using Clevenger type apparatus and by hydrodistillation. Results and DiscussionAnalysis of variance showed that the effect of the diversity among the genotypes on morphological, agronomical and essential oil yield parameters of wild mint was significant (P≤0.01). The results of this study showed that Mentha longifolia L. herb has a high diversity under the same culture conditions among genotypes collected from 20 regions of Iran. Correlation result shows that vegetative organs have more effect on the essential oil content than the reproductive organs. This may be due to the distribution of essential oil accumulation and storage sites, which requires further research in this regard. The study of vegetative and reproductive characteristics suggests that the genotypes of the dry and semi-arid climates have different conditions, which may causes the separation of their genotypes compared with the other genotypes. The bi-plot, based on PC1 and PC2, reflects the relationships between the studied genotypes. The results of bi-plot of cluster analysis confirmed that genotypes were divided into two main groups based on agronomical and morphological traits. Conclusion Finally, plants of genotype G13 belongs to Hormozgan province and then G16 genotype belongs to Khuzestan province were selected because of more biomass, more aerial part volume and also the most essential oil performance compared to the other genotypes. Desirable traits for the aerial part such as the time of flowering, leaf length, leaf width, plant height, the highest number of leaves in the stem and internode distance are important traits that should be considered. In addition, the cultivation of these genotype in order to the further production can be the great help in the domestication of this species and, given the fact that the diversity is a precursor of breeding, this research can be an introduction for future breeding operations. However, further research is needed to confirm the phytochemical superior genotypes.
Research Article
Postharvest physiology
Behzad Kaviani; Mohammad Reza Safarimotlagh; Sara Hataminejad
Abstract
Introduction Chrysanthemum (Chrysanthemum morifolum L.) is one of the most important cut flowers in the world, which currently ranks second in the world after rose in terms of economy and cultivation. Stem end blockage and water stress are two problems in decreasing the vase life of chrysanthemum ...
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Introduction Chrysanthemum (Chrysanthemum morifolum L.) is one of the most important cut flowers in the world, which currently ranks second in the world after rose in terms of economy and cultivation. Stem end blockage and water stress are two problems in decreasing the vase life of chrysanthemum cut flowers. Cut flowers undergo physiological and biochemical alterations which often lead to an early senescence. Steps to delay the senescence process rely on consideration of many aspects of handling process particularly the preservative solution that will influence the quality and longevity of the flowers. Many flowers are harvested before they are fully developed, to ensure a long postharvest life and to minimize mechanical damages which may occur during handling. Many researches have been performed to prolong the vase life of chrysanthemum cut flowers with different treatments like essential oils, organic acids and nanoparticles. Essential oils are aromatic oily liquids obtained from some aromatic plant materials. In vase solution, microorganisms cause stem obstruction and accelerate the aging of petals. Microorganisms and their toxic products restrict water uptake by blocking the end of the stem. Water balance, which is an important factor in maintaining the quality and longevity of cut flowers and the inability to uptake water are the main causes of senescence. The presence of disinfectants in the vase solution prevents the growth of microorganisms, protects the vessels against disintegration, and ultimately increases the vase life. Most of nanoparticles have antibacterial effects and their application in vase solution hinders microorganism growth and vascular blockage. Nanoparticles have high area-to-volume ratio, high efficiency, and low toxicity. Some nanoparticles penetrate into the cells of bacteria, disrupt their respiration chain, and cause disorder in their cell division, thereby killing them. They also inhibit the accumulation of bacteria in vase solution and stem end of cut flowers. Various studies have reported the positive impact of nanoparticles on decreasing microbial load, reducing transpiration from leaf surface, and preserving water uptake. Studies on postharvest longevity of chrysanthemum cut flowers using these compounds is low. Therefore, the aim of the present study was to evaluate the effect of orange spring essential oil, fulvic acid and cupper nanoparticles on vase life and some physiological parameters of chrysanthemum cut flowers. Materials and MethodsThe experiment was performed based on randomized completely design with three replicates in order to investigate the effect of different levels of fulvic acid (50, 100 and 150 mg l–1), orange spring essential oil (10, 30 and 50%) and copper nanoparticles (5, 10 and 20 mg l–1) in comparison to control (distilled water + 3% sucrose + 30 mg l–1 8-hydroxyquinoline sulphate) on postharvest parameters of chrysanthemum cut flowers. Measured parameters included vase life, solution uptake, vase solution bacterial population, stem end bacterial population, decreasing the brix degree, decreasing fresh weight, dry matter, total chlorophyll content, carotenoid content, protein content, and peroxidase and superoxide dismutase activity. Data were analyzed by SPSS statistical software package and means were compared with the LSD test at the probably level of 95%. Results and DiscussionAccording to the obtained results, the effect of treatments on improving the quality characteristics of chrysanthemum cut flowers after harvest was significant. Results showed that the high vase life (16.33-17.00 days) was obtained with all three copper nanoparticles concentrations. The vase life of chrysanthemum cut flowers was extended to 17 days by the addition of 20 mg l–1 copper nanoparticles in preservative solution in compared to control with 14 days’ vase life. Least solution bacteria colonies was obtained through the use of 5 mg l–1 copper nanoparticle. On the other hand, least stem end bacteria colonies was obtained using 10 and 30% orange spring essential oil. Solution uptake in these treatments was high, too. The effects of different treatments on some other physiological traits and antioxidant enzymes activity were measured. Many studies have been carried out on the effect of essences (herbal extracts) as antimicrobial agents on prolonging the vase life of cut flowers. In most of these studies, these essences could prolong postharvest life. Essences have been studied with the intension of incorporating them into integrated pest management to avoid or reduce the use of synthetic bactericides and fungicides. They also have antioxidant properties. Application of herbal extracts improved water absorption in rose cut flowers by preventing the vessel obstruction. The above results are similar to the results of this study. In most cases, when the cut flowers were treated with nanoparticles, they exhibited longer vase life, higher water uptake, and lower stem-end bacteria than the control flowers.
Research Article
Ornamental plants
Ali Sahari Moghaddam; Behzad Kaviani; Ali Mohammadi Torkashvand; Vahid Abdossi; Ali Reza Eslami
Abstract
IntroductionYew or English yew (Taxus baccata L.) from the family of Taxaceae is an ornamental shrub that is used in various industries. Root induction and formation process at the base of stem cuttings of yew is slow. This species is in danger of extinction. Stimulation of rooting in cuttings causes ...
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IntroductionYew or English yew (Taxus baccata L.) from the family of Taxaceae is an ornamental shrub that is used in various industries. Root induction and formation process at the base of stem cuttings of yew is slow. This species is in danger of extinction. Stimulation of rooting in cuttings causes the plant to grow faster. Polyamines are a group of plant growth regulators that play a variety of roles, including cellular differentiation and development and stimulation of adventitious root production. Some yew habitats have been destroyed because of neglect, destruction, livestock and ineffective exploitation. The yew is propagated by seeds or through cutting and grafting. Propagation of yew through seed is difficult and obtained plants show non-uniformity. Therefore, vegetative propagation is used to produce plants similar to the mother plant. The proliferation of the plant through leafy stem cutting is one of the most famous and the best propagation methods due to the preservation of the genetic structure and uniformity. Increasing the rooting capacity of trees and shrub cuttings is being carried out with a variety of plant growth regulators around the world. Putrescine has shown a better response in compare with other polyamines. The stimulation effect of exogenous application of polyamines, especially putrescine, was shown on the rooting of several plants’ cutting. Literature evaluation showed that there is not any study on the effect of polyamines on the rooting of the yew stem cuttings. Therefore, the aim of this research was to improve the rooting conditions of difficult-to-root cuttings with different concentrations of putrescine (a type of polyamine). Materials and MethodsIn order to investigate the effect of different concentrations of putrescine, an experiment was performed based on a completely randomized block design with 4 replications. Treatments included 0 (as a control), 500, 1000, 2000, 3000, 4000 and 5000 mg.l–1 of putrescine concentrations. In October, 25 cm of the end of the shoot of 5-years-old mother plants were cut and used as hardwood cuttings. The cuttings diameter was 2.5-3 mm. The lower ends of the shoot cuttings were kept at different concentrations of putrescine for 10 seconds and then placed in the cultivation bed. In this study, root percentage, number of roots, root length, stem length, shoot number, leaf number and survival percentage of cuttings were measured. Cuttings cultivation bed was perlite, cocopeat and peat moss. To prevent possible contamination, the bottom of the cuttings were immersed in a 2/1000 fungicide solution of Berdofix a week befor cutting preparation. Results and DiscussionThe results of analysis of variance showed that different concentrations of putrescine on all traits were significant at 1% probability levels. The results of mean comparison showed that the largest number of roots (6.50 per plantlet) and the highest root length (7.70 cm per plantlet) were observed in cuttings treated with 500 mg.l–1 putrescine. The highest number of shoots (5.50 per plantlet) and the highest rooting percentage (97.50) were obtained in cuttings treated with 2000 mg.l–1 of putrecine. The maximum number of leaves (41.25 per plantlet) was counted in cuttings treated with 3000 mg.l–1 of putrescine. Yew can be propagated successfully by stem cuttings. Natural conditions propagation and in vitro propagation beside cryopreservation are effective approaches to conserve plants particularly those putted in the red list. Plant growth regulators have an effective role in increasing the rooting of difficult-to-root cuttings of trees and shrubs. The exogenous use of polyamines as a new group of hormones stimulated root production in some cuttings. Peach × almond hybrid cuttings treated with 2 mM putrescine for 5 min showed the highest rooting percentage, root number and root length with the best quality. Putrescine is capable to influences on other plant growth regulators and has less toxicity than most of them. Polyamines stimulate cellular division in dissection place cells of cuttings such as cambium and phloem. The exogenous application of these compounds, especially putrescine during the root formation phase resulted in an increase in endogenous putrescine, endogenous auxin and peroxidase enzyme activity. In the cutting of the leafy stem of Corylus avellana L., the use of putrescine stimulated rooting. The study, like the present study, confirmed that putrescine can be useful for increasing rooting percentage and root quality. Putrescine had an effective role in the rooting of the stem cuttings. The present study revealed that the lowest root number was counted in cuttings that were not treated by putrescine (control). Polyamines (spermine, spermidine and putrescine) increased rooting percentage and root growth by stimulating root cell division (increased mitotic index of tip root cells) in regenerated pine (Pinus virginiana Mill.) seedlings. Polyamine biosynthesis and antioxidant enzymes activity were increased during root induction and formation. The exogenous application of spermidine in the apple (Malus prunifolia) stem cutting stimulated rooting by changing the concentration of some hormones. Spermidine regulated the expression of genes involved in the production of auxins. The study aimed to investigate the cellular-molecular effect of polyamines on the structure and development of roots in Arabidopsis showed that these organic compounds adjusted the size of the root meristematic zone during the effect on both symptomatic accumulations of hormones and reactive oxygen species (ROS). The same and different results are presented with the present findings by some other researchers. The main cause of these different results is the difference in the amount and balance of endogenous hormones, including polyamines in different species. Plant genotype, type of cuttings, cutting age, environmental factors, nutritional status especially type and amount of carbohydrates in the plant, the transfer rate of these carbohydrates from leaves to roots, the presence and the amount of phenolic compounds, nitrogen compounds, phonological stages and cutting season also play an effective role in these differences.
Research Article
Pomology
Akram Heydari; Saeid Daghighi; Farhad Azarmi-Atajan
Abstract
Introduction Pistachio (Pistacia vera L.) is an important crop in Iran our country and has a unique position in export goods. The amount of pistachio production in Iran has decreased by 50% compared to 2017. The low yield of pistachios per unit area is due to the management problems of orchards, ...
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Introduction Pistachio (Pistacia vera L.) is an important crop in Iran our country and has a unique position in export goods. The amount of pistachio production in Iran has decreased by 50% compared to 2017. The low yield of pistachios per unit area is due to the management problems of orchards, and among these, nutrition and fertilizer management is of special importance. Among the nutrients that are important in pistachio nutrition, especially when the brain is full, are nitrogen and potassium. Humic acid can also improve physical, chemical and biological soil properties and stimulate growth via its effects on plant metabolism.The aim of this study was to investigate the effect of application of some nitrogen fertilizers with different levels of potassium sulfate and humic acid on growth, yield and photosynthetic pigments of pistachio Badami Sefid-e-Mahvalat variety. Materials and Methods This research was conducted as a factorial experiment based on a randomized complete block design with three replications at the Mahvalat during 2019-2020. The first factor consisted of nitrogen fertilizers at 4 levels (control, urea, ammonium sulfate and ammonium nitrate). The second factor was potassium sulfate fertilizer at 2 levels of zero and 250 g per tree and the third factor was humic acid fertilizer at 2 levels of zero and 45 g per tree which as a manure pits after the formation of the cluster and at the same time with the growth of the bony shell in the shade of the tree where the capillary roots are active. At the end of the experiment, morphophysiological traits were measured and recorded. In each tree, three branches were selected in different directions and the length of the current branch was measured in meters using centimeters. The diameter of the middle of the branch was measured with a caliper. From the collected clusters, 100 fruits were randomly selected, and the number of indehiscence fruits and the number of blank fruits were counted and finally expressed as a percentage. Measurements of chlorophyll a and b, total chlorophyll and carotenoids were determined using Arnon method. The experimental data was analyzed by SAS software and the significant differences among the treatment were tested by LSD test. Results and DiscussionThe results of analysis of variance of data in two years of experiment showed that experimental treatments had a significant effect on pistachio growth and yield. The results of the first year showed that the combined treatment of urea and 250 g of potassium sulfate and 45 g of humic acid had the highest diameter and branch length, indehiscence percentage, chlorophyll a, b and total and the lowest pistachio blank percentage. The highest yield in the first year was obtained from the combined use of ammonium sulfate, 250 g of potassium sulfate and 45 g of humic acid. Combined application of ammonium nitrate and 250 g of potassium sulfate and 45 g of humic acid resulted in the highest diameter and branch length in the second year of the experiment. The highest indehiscence percentage and carotenoids and the lowest amount of pistachio blank percentage in the second year were obtained from the combined treatment of ammonium sulfate, 250 g of potassium sulfate and 45 g of humic acid. Most chlorophyll a, b and total were obtained from combined consumption of urea, 250 g of potassium sulfate and 45 g of humic acid. The highest yield of the second year was obtained due to urea consumption, 250 g of potassium sulfate and 45 g of humic acid. Nitrogen is a component of amino acids, proteins, nucleic acids and enzymes and plays a major role in plant physiology, vegetative growth, chlorophyll formation and fruit and fruit production. Potassium is also one of the elements required by the plant that plays an important role in photosynthesis and transport of carbohydrates. The organic acids in humic acid cause the chelating of many nutrients and increase their availability to the plant. By using these substances and its positive and stimulating effects on plant growth and increasing root growth and its absorption power, nutrient uptake, yield is increased.
Research Article
Growing vegetables
Parastoo Molaei; Fatemeh Nekounam
Abstract
IntroductionLettuce (Lactuca sativa L.) from the Asteraceae family is one of the most important vegetables due to its rapid growth and commercial value. Currently, the market share of organic vegetables is constantly increasing due to customer demand for safer and healthier food. Excessive use of pesticides ...
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IntroductionLettuce (Lactuca sativa L.) from the Asteraceae family is one of the most important vegetables due to its rapid growth and commercial value. Currently, the market share of organic vegetables is constantly increasing due to customer demand for safer and healthier food. Excessive use of pesticides and chemical fertilizers threatens the environment and leads to the production of unsafe food products. Therefore, it is important to find alternatives instead of using pesticides chemical methods to manage powdery mildew. Generally, biotic and abiotic stresses are among the factors that have a destructive effect on growth and development, performance, and production of plant biomass. Fungicides can be the most effective method of controlling the powdery mildew disease, but this pathogen can develop resistance to fungicides. Rhizosphere bacteria are among the living agents that, by producing some allelochemicals, cause the dissolution of soil nutrients, increase the availability of nutrients, and induce plant resistance to biotic and abiotic stresses. In addition, they enhance host plant growth through an indirect mechanism, including the inhibition of disease-causing pathogens by releasing some allelochemical substances. The biological control of powdery mildew disease with the use of rhizospheric bacteria in lettuce and zucchini has been reported. Material and MethodsTo evaluate the biological control of powdery mildew fungus with plant growth promoting rhizobacteria (PGPR) and effects on yield and quality of New Red Fire greenhouse lettuce, an experiment was carried out in a completely randomized design with three replications in the Research greenhouse of University of Zanjan during 2020. Experiment treatments consisted of five levels of PGPR (Pseudomonas vancouverensis- VPM, Pseudomonas Koreensis- KPM, Pantoea agglomerans- PAPM, Pseudomonas putida- PPM, and one level of combined bacteria (Pantoea agglomerans+ Pseudomonas Koreensis+ Pseudomonas putida+ Pseudomonas vancouverensis- MBPM, one level of chemical fertilizer 100% N, P and, K according to soil test results- NPK, and two control treatment without powdery mildew condition (C) and under powdery mildew conditions (CPM).The “New Red Fire” lettuce seeds were surface sterilized with 0.5% (v/v) sodium hypochlorite for 10 min and germinated at 20ºC. After germination, seedlings with similar size were transplanted into pots. Plants were grown under greenhouse condition with 60/70 % (day/night) relative humidity, 15/18 °C (day/night) temperature. Inoculation of pathogenic fungi was done 40 days after seed germination. Plants were harvested after 75 days. The chlorosis and necrosis spots number on each plant, plant fresh weight, plant dry weight, leaf number, total chlorophyll, total phenol and flavonoids contents, antioxidant activity, anthocyanin content, and catalase and peroxidase enzyme activity were measured. ResultsThe results showed that the application of potassium and phosphorus solubilizing bacteria and NPK fertilizer significantly increased plant growth compared to control plants under the stress of powdery mildew fungus. The highest plant fresh weight, percentage of plant dry weight, and leaf number were obtained with the application of combined potassium and phosphorus solubilizing bacteria treatment and 100% N fertilizer under the biostress. The maximum total chlorophyll was obtained with the application of Pseudomonas koreensis and Pantoea agglomerans bacteria. 100% reduction of necrosis spots was obtained by using the Pantoea agglomerans bacteria. The maximum of chlorosis spots (increase of 55.8%) and necrosis spots (an increase of 88.8%), total phenol (an increase of 52%), total flavonoids (an increase of 39.3%), catalase (an increase of 28.4%) and peroxidase enzymes activity (49.1%) were obtained with application of NPK fertilizer. No significant effect on antioxidant activity was observed with the application of chemical fertilizer and rhizosphere bacteria under the Biostress. The maximum anthocyanin contents were obtained with the application of Pseudomonas koreensis. ConclusionAccording to the results, the application of NPK chemical fertilizer and seed pretreatment of lettuce with PGPR increased the value of antioxidant compounds including total phenol, flavonoid, and anthocyanin contents and catalase and peroxidase enzymes activity under powdery mildew conditions. Inoculation of lettuce seeds with PGPR, in addition to improve plant growth under biological stress conditions, increased anthocyanin contents and induced the resistance of lettuce plants to powdery mildew. Seed pretreatment with PGPR reduced chlorosis and necrosis spots in leaves. Therefore, pretreatment of lettuce seeds with PGPR instead of chemical compounds (fertilizers, pesticides and plant growth regulators) is recommended to improve the yield and quality of lettuce under powdery mildew conditions.
Research Article
Pomology
Sayeede Khodaei; Ebrahim Ganji Moghadam; Mahboobeh Zamanipour
Abstract
IntroductionSince Iran is one of the arid and semi-arid regions of the world and due to the great importance of water in agriculture, it is very important to conduct research to improve drought stress in order to produce more quality products. In this regard, this study was conducted to investigate the ...
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IntroductionSince Iran is one of the arid and semi-arid regions of the world and due to the great importance of water in agriculture, it is very important to conduct research to improve drought stress in order to produce more quality products. In this regard, this study was conducted to investigate the effect of mycorrhiza species on some morphological and physiological characteristics of peach seedlings under drought stress. Arbuscular mycorrhizal fungi coexist with the roots of various plants and have a broad effect on their growth. These fungus are effective in the initial establishment of the plant under drought conditions. Arbuscular mycorrhizal fungi increases plant resistance to dehydration by increasing growth and uptake of nutrients, especially phosphorus. Matherials and MethodsIn order to investigate the effect of three species of Arbuscular mycorrhizal fungi on some vegetative characteristics and phosphorus absorption of peach seedlings under drought stress conditions, a factorial experiment was conducted based on a randomized complete block design with four replications. The experimental factors included: drought stress at four levels (100, 80, 60 and 40 percent of field capacity) and the second factor application of mycorrhizal fungus at four levels: application of three species of mycorrhiza fungi and three species of fungi, each in three concentration (75, 100, 125 g in a pot) with chemical fertilizer (100 g triple super phosphate for each pot) and fertilizer (without mycorrhiza) and control (without fertilizer and mycorrhiza). The measurements were comprised root traits, stem diameter, vegetative growth of branches, leaf area index, vegetation index, relative leaf water content, chlorophyll fluorescence, leaf electrolyte leakage, leaf phosphorus and colonization root percent. Results and DiscussionResult showed that application of mycorrhizal fungi seems to be effective in reducing the effects of dehydration stress. The use of these fungi had a positive effect on reducing leaf electrolyte leakage under severe dehydration. According to the results obtained in this experiment, the highest efficiency in drought stress conditions was observed in G. mosseae and G. intraradices. Under drought stress conditions, the lowest values of root volume, greenness index, chlorophyll fluorescence, leaf electrolyte leakage, root colonization and leaf phosphorus content were observed. With increasing of drought stress, all of the mentioned traits reduced and mycorrhiza fungi had a positive significant effect on all studied traits. In this study, it was found that with increasing stress intensity, the traits were negatively affected and led to irreparable damage to the product. Therefore, it is expected that by preventing or minimizing the effects of stress, an effective step was taken to increase performance. The significant decrease in root colonization with increasing stress is probably due to the decrease in the growth of hyphae. The most important step after spore germination is the growth of hyphae resulting from germination, which plays an essential role in root colonization. Apparently, hyphae growth is more affected by osmotic potential than spore growth. The results obtained from this research showed that the roots of peach seedlings have significant symbiosis potential with arbuscular mycorrhizal fungi (Peymaneh & Zarei, 2013). According to Miyashita et al. (2005) Leaf photosynthesis activity can be used as a useful tool for classification of drought tolerant plants. Sajjadinia et al. (2010) regarding the relative water content and photosynthesis of several pistachio cultivars reported high correlation and high diversity in different stages and cultivars and stated that the decrease in relative water content strongly reduces transpiration, stomatal conductance and photosynthesis, which our results are consistent. With the escalation of tension, the greenness index also decreased; So that in the conditions of severe stress (40% of crop capacity), the amount of greenness index reached the lowest value. In the conditions of severe stress due to interruption of continuous irrigation, the plants entered from the stage of mild stress to the stage of severe dry stress, which seems that under these conditions, the decrease in the concentration of chlorophyll, in addition to the decrease in the amount of synthesis, is caused by the decomposition of chlorophyll due to the increase in the amount chlorophyllase, peroxidase and phenolic compounds. According to Schutz and Fangmier (2001), the decrease in the amount of chlorophyll in stress conditions is related to the increase in the production of oxygen radicals in the cell. These free radicals cause peroxidation and as a result the decomposition of this pigment. The greenness index is considered one of the most important growth parameters, which is reduced by drought stress conditions, and the results indicate that the treatment of mycorrhizal fungi in all three types of inoculated mushrooms has improved the greenness index and the adverse effects It has removed the drought stress to a great extent (Figure 6), which can be attributed to the improvement of water and food absorption by mycorrhizal roots (Larsson et al., 2008). Conclusion In general, this study showed that the best treatment related to the mycorrizha fungi was mosseae, which had the most effect on reducing the negative effects of stress
Research Article
Growing vegetables
Farzad Abdollahi; Alireza Motallebi-Azar; Gholamreza Gohari; Bahram Dehdar; Amir Kahnamoii; Fatemeh Shariat
Abstract
IntroductionGrapheneis one of the new carbon nanomaterial that has unique physical properties and potentially important biological applications. Nanosheet Graphene Oxide has shown great potential to improve plant performance in various areas. Microtuber production technology is also used as a tool to ...
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IntroductionGrapheneis one of the new carbon nanomaterial that has unique physical properties and potentially important biological applications. Nanosheet Graphene Oxide has shown great potential to improve plant performance in various areas. Microtuber production technology is also used as a tool to reduce the time needed to produce economic plant resources, increase the quality of seed tubers, and produce microtubers throughout the year. The aim of this study was to evaluate the effect of Nanosheet Graphene Oxide on the improvement of micropropagation and microtuberazation in potato var. Agria under in vitro conditions. Materials and MethodsSingle node explants obtained from in vitro virus-free plantlet (maintained in tissue culture laboratory, Department of Horticultural science, University of Tabriz) were cultured into modified Murashige and Skoog (MS) medium containing four concentrations of Nanosheet Graphene Oxide (0, 25, 50 and 75 mg/L) carried out in the completely randomized design (CRD) with four replications and kept at 25±2 degree centigrade and a photoperiod of 16 hours of light. The proliferation traits such as leaf length, leaf width, plantlet fresh weight, number of leaves and shoots were recorded. Then, single node explants were transferred to Murashige and Skoog (MS) medium with four concentrations of Nanosheet Graphene Oxide (0, 25, 50 and 75 mg/liter) and kept for two months in complete darkness and at 18±2 ºC and microtuber production indices such as microtuber number, diameter, length and weight, microtuberization percentage, shoot length, microtuber with dormancy were measured. Results and DiscussionThe results of analysis of variance showed that different concentrations of Nanosheet Graphene Oxide had a significant effect on all traits in proliferation and microtuberization stages. Among different levels of Nanosheet Graphene Oxide, application of 75 mg/L showed the best response for leaf length, leaf width, and plantlet fresh weight, followed by 50 mg/L for the number of leaves and shoots, and lastly, 25 mg/L for shoot length. At a concentration higher than 50 mg/L (75 mg/L graphene oxide), the number of leaves not only remained constant but also showed a decreasing trend. Effect of different NGO concentrations on the shoot length showed that there was no significant difference between different concentrations of NGO and the shoot length remained constant, but the difference between the control treatment and NGO was significant. The maximum shoot length was obtained at a concentration of 25 mg/l NGO. The different concentrations of NGO had significant effect on all microtuberization traits at 1% probability level. Mean comparison results for different concentrations of NGO showed that the highest value of the microtuber length, diameter and number were obtained at 25 mg/liter NGO. However, all microtuber traits were not increased at above 25 mg/liter NGO. With the increase in NGO concentrations, the yield of microtuber weight and microtuberization rate remain constant, and it is also possible that these traits will decrease significantly with the increase NGO concentration. The highest yield of microtuber weight and microtuberization rate were obtained at the 25 mg/L NOG, and higher concentrations did not increase them. There was a significant difference between different concentrations of NGO and the control treatment in the number of lateral shoots, so that the maximum number of lateral shoots was obtained at a concentration of 25 mg/L of NGO. Also, concentrations above 50 mg/L of NGO had less effect on the number of lateral shoots and with increasing concentration, the number of shoots decreased significantly. The maximum microtuber weight was obtained at high concentrations of NGO. In other words, with the increase of NGO concentration, the microtuber weight increased, and the most effective concentration was 75 mg/L of NGO for this trait. Although all concentrations of NGO are favorable for this purpose, it is possible that the concentration of 25 mg/l is the most NGO concentration. ConclusionThe results of this research showed that the of 50 and 75 mg/L of Nanosheet Graphene Oxide were the best concentrations micropropagation and microtuberization. 25 mg/L of Nanosheet Graphene Oxide was most efficient concentration . Although these experiments were performed without the use of growth regulators, the addition of Nanosheet Graphene Oxide to the medium increased micropropagation and microtuberization. Therefore, Nanosheet Graphene Oxide can be used as a tool for efficient micropropagation and increasing the quantity and quality seed tubers.
Research Article
Medicinal Plants
Mina Amani; Saeideh Alizadeh Salteh; Mohsen Sabzi-Nojadeh; Mehdi Younessi Hamzekhanlu
Abstract
IntroductionMedicinal plants have long had a special place in the traditional agricultural system of Iran and the use of these plants as medicine to prevent and treat diseases has been considered by traditional medicine experts since ancient times. Medicinal plants with rich sources of secondary ...
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IntroductionMedicinal plants have long had a special place in the traditional agricultural system of Iran and the use of these plants as medicine to prevent and treat diseases has been considered by traditional medicine experts since ancient times. Medicinal plants with rich sources of secondary metabolites provide the basic active ingredients of many medicines. Although the biosynthesis of secondary metabolites is genetically controlled, but their construction is strongly influenced by environmental factors. One of the important climatic factors that affect the distribution of plants around the world and can cause morphological, physiological and biochemical changes in the plant is the lack of available water. Basil (Ocimum basilicum L.) seems to show little resistance to water stress. For this reason, there is a need for protective mechanisms for the basil plant against stress due to water shortage. Plants are able to reduce or eliminate the effects of water shortage stress by coexisting with a number of soil microorganisms. Coexistence relationship plant with T. harzianum fungi is one of the ways to reduce dehydration in plants. These mushrooms by altering some of the root properties and absorbing nutrients in the host plants, they reduce the destructive effects of water shortage stress. Observing the positive effect of these fungi in increasing the absorption of nutrients from the soil, improving plant water relations, increasing water use efficiency in plants and finally increasing plant resistance to water deficit stresses on the one hand and on the other hand. The existence of water crises in different countries has prompted researchers to further study this aspect of the symbiotic relationship between the host plant and Trichoderma harzianum. Materials and MethodsPresent study was performed to investigate the effect of T. harzianum on the antioxidant content of Ocimum basilicum under water deficit stress. It is also intended to evaluate the effects of an endophytic fungi namely T. harzianum on the shoot yield, photosynthetic pigments, content and yield of essential oil from O. basilicum under water deficit stress. All experiments were performed as the factorial based on completely randomized design blocks with three replications in greenhouse condition. The experimental factors were the different irrigation regimes including 100, 75, 50 and 25% of field capacity and two concentrations of the T. harzianum (106 and 109 CFU/ml). At the beginning of flowering, water deficit stress was applied at four levels of 25, 50, 75 and the control treatment (100 percent) of field capacity until three weeks later. The application of water stress was such that the pots were weighed daily and the moisture deficiency in each treatment was removed by watering the pots until reaching the desired treatment level. After applying the stress, sampling and measuring traits were done at the full flower stage. After the plants reach the full flowering period, various traits including plant height, number of leaves, fresh and dry weight yield of the plant (as the economic yield of basil) and fresh and dry weight yield of roots per square meter, chlorophyll a, b, total (T), carotenoid, colonization percentage, yield and essential oil content were measured in all the plants in the pots. Results and DiscussionIncreasing the level of water stress reduced the economic performance of basil (O. basilicum). Coexistence with Trichoderma reduced the destructive effects of dehydration on the plant. With the application of dehydration stress, the essential oil content increased in mild and moderate stresses, but the yield of essential oil did not differ significantly from the control and plant height, number of leaves and plant pigments decreased under dehydration stress. According to the experimental results, it can be said that Trichoderma with a population density of 106 (spores per ml of inoculum) had a better effect on most growth indices, while the effect Trichoderma with a population density of 109 (spores per milliliter of inoculum) on important traits such as shoot fresh weight yield (212.2 g), percentage (0.7%) and essential oil yield It was higher. According to the obtained results, it can be stated that inoculation of basil with Trichoderma increased the percentage and yield of essential oil in both water stress and non-stress conditions, and considering that in cultivation of plants the goal is to increase the effective substance. It is in these plants. ConclusionFinally, the results indicated that the use of Trichoderma mushroom in comparison with the control (without inoculation with the fungus) under water stress conditions has the ability to improve plant growth and leads to an increase in plant efficiency under water stress conditions.
Research Article
Medicinal Plants
Homeyra Hatami; Ghorbanali Rasam; Alireza Dadkhah
Abstract
Introduction Mint has been used both as a medicinal and aromatic plant since ancient times. Peppermint volatile oil is one of the most important essential oils and has strong antimicrobial activity. The stage at which the maximum essential oil is obtained from the plant is not necessarily ...
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Introduction Mint has been used both as a medicinal and aromatic plant since ancient times. Peppermint volatile oil is one of the most important essential oils and has strong antimicrobial activity. The stage at which the maximum essential oil is obtained from the plant is not necessarily the stage at which the plant has the most biomass, therefore, the appropriate time for harvesting the plant should be determined according to the maximum amount of the effective substance and the yield of dry matter. In most of the methods of producing medicinal plants, quick access to the equipment for extracting effective substances is not possible, especially at high levels, and this requires drying a large part of the plants and extracting the effective substance in subsequent times. The quality of dried medicinal plants is defined by the content of their biologically active compounds. This study was aimed to determine the best time to harvest peppermint and the effect of different drying methods on the shoots biochemical compounds. Materials and MethodsIn order to increase the yield of peppermint medicinal plant essential oil, two separate experiments were designed and conducted in Shirvan Higher Education Complex (N 26 37', E 45 57', altitude 1067 m) in 2015. The aim of first experiment was finding the best harvest time at three levels (Before flowering, at flowering 50 and 100%) and the second experiment was finding the best method for shoot drying with nine levels (Microwave radiation at 90, 180, 360, 600 and 900 watts; Oven at 40 and 60°C; Shade; and Sun), were based on a completely randomized block design (CRBD) and a completely randomized design (CRD), respectively. In the spring of 2015, tillage operations were carried out and after preparing the land, 9 plots (2 × 3 meters) were created in it. The distance between the plots was considered 1.5 m. Rizhomes of peppermint plant was obtained from Mashhad Agricultural and Natural Resources Research Center and transplanted at 20 × 30 cm intervals on May 26. Some morpholocial and biochemical traits were measured. Essential oil extraction was done by distillation method with water and essential oil components were determined by GC/Mass method. Results and DiscussionThe effect of harvesting time was significant (p≤0.01) on the plant height, number of leaves per plant, wet and dry yield of peppermint plant. The height of the plant after 50% flowering stage did not show any significant difference, but the other investigated traits include the number of leaves per plant, the wet and dry yield of the plant, the yield of essential oil in terms of wet and dry weight, and the inhibition of free radicals in the branches in shoots harvested at the time of full flowering had the highest amount, which showed a statistically significant difference. The yield of essential oil in terms of dry matter in the full flower stage increased 1.8 times compared to the 50% flowering stage and 4.6 times compared to the pre-flowering stage. The percentage of essential oil components was also affected by the harvest time, and the highest amount was observed in the full flowering stage (98.92 percent), include the highest amount in menthol (42.39 percent) and menthone (19.13 percent). The use of micro rays caused the shortest drying time, so that with the increase of power of micro rays, the drying time decreased and the shoots were dried in 0.16 hours at the power of 900 watts. The oven application at 60 and 40 °C were statistically ranked second and third in terms of drying speed with 10 and 14.6 hours. Sun and shade drying needed 46 and 109.6 hours to reach constant moisture, respectively. The highest amount of essential oil was obtained in the shade drying method (2.13%) and the lowest amount was observed in the microwave application at 900 and 600 watt. (0.01%). After shade drying, the highest amount of essential oil was observed in the oven method at 40 °C (2%) and in the sun drying (1.44%). According to the results of this study, it is recommended to harvest the branches at the time of full flowering and dry them using oven at 40 °C to obtain more essential oil yield of peppermint shoots. ConclusionIn general, the harvesting time has a significant effect on the morphological characteristics and essential oil of the peppermint shoots. Harvesting peppermint in the full flowering stage resulted in the highest amount of essential oil and essential oil yield. The maximum height and number of leaves in the plant were obtained by harvesting at the time of full flowering, but the maximum wet and dry yield of shoots was observed at the harvest of 50% of flowering. The amount of menthol and menthone as the most important compounds of mint essential oil in the full flowering stage was higher than the other two harvesting times. Also, based on the results of this experiment, different methods of drying peppermint plant have various effects on the essential oil amount of peppermint shoots. The shortest time until drying was related to the use of microwave, oven, sun and shade, respectively, and the highest yield of essential oil was obtained in shade, oven at 40 °C, microwave at 90 watt and sun, respectively.
Research Article
Pomology
Zohre Rohi Vishekaii; Ali Soleimani; Mahmood Ghasemnejad; Akbar Hasani
Abstract
Introduction Olive tree, with a thousand years of cultivation history, is one of the most important horticultural crops in Iran and has always played an important economical role for orchardists. In olive orchards traits such as an increased formation of incomplete flowers, low yield of fruits and ...
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Introduction Olive tree, with a thousand years of cultivation history, is one of the most important horticultural crops in Iran and has always played an important economical role for orchardists. In olive orchards traits such as an increased formation of incomplete flowers, low yield of fruits and oil are often found as major problems. It should be noted that these traits are affected by numerous environmental and management factors from which the nutrition status is one of the most important ones. Proper nutrition plays an important role in both olive fruit and oil yield. There is a wide range of fertilizer compounds with different formulas and efficiencies available in the world market, among which nano-products are becoming increasingly popular. However, there is limited information on their efficacy in different plant species. Materials and MethodsIn order to evaluate the impact of fertilizers on olive cultivation, a research was conducted during two successive years from 2019 to 2020 in a commercial orchard on 15 year old olive tree cv. ‘Zard’, in Manjil city of Guilan province. Foliar application included five treatments using two types of fertilizers; nano (nano-chelated nitrogen and potassium: nano-NK) and chemical fertilizers (urea and potassium nitrate; NK). Treatments involved application of two concentrations from each fertilizers sources; 1.02g and 0.81g (nano-N1K1 and N1K1), 1.36 g and 1.08 g (nano-N2K2 and N2K2) of pure nitrogen and potassium, respectively. Foliar application was conducted in four stages bud-swelling, before blooming, pit hardening and shortly after harvest of table olive. Spraying with water was considered as the control. The nano-chelated fertilizers were obtained from Khazra Company, Teheran, Iran (http://en.khazra.ir). Spraying with water was considered as control. The experiment was performed in a randomized block design with three replications. The measurement of leaf nutrient status and its chlorophyll and carbohydrate contents were carried out at two times each growing season; in August (during pit hardening stage) and October (shortly after the harvest of table olive). At the green ripening stage, fruits were collected and weighted to determine fruit yield. At the end of the experiment quantity and quality traits of oil were measured. Results and Discussion The results showed that the trees under N2K2 treatment had the highest yield. In terms of mineral content, both forms of fertilizers increased the concentration of nitrogen and potassium leaf elements compared to the control trees. Chlorophyll content was affected by nano-N1K1 foliar application and carbohydrate content was affected by nano-N1K1 in the pit hardening stage and nano-N2K2 in shortly after the harvest of table olive. Nano-N1K1 treatment with the lower crop load not only increased oil content but also improved quality characteristics of olive oil (free fatty acids, peroxide value, specific ultraviolet absorbance K232, K270 and contents of pigments), total phenol content, antioxidant capacity and fatty acid composition. Generally, the results showed that olive trees responded well to fertilizer feeding. These trees produced better crop and higher quality oil in comparison with control trees. According to the results, fruit yield is better under urea and potassium nitrate treatment, and the quality of olive oil is more stable after nano-chelated nitrogen and potassium foliar application. It seems that the reason for the high amount of fruit yield with N2K2 in comparison to the slow-release property of nano-fertilizers is that using nitrogen and potassium in the form of ordinary chemical fertilizer regulates the biosynthesis, conversion and rapid translocation of assimilates and mineral elements into reproductive structures, which resulted in soaring yield. We assumed that nano-N1K1 foliar spray in the pit hardening stage and shortly after the fruit harvest for table olive might export the assimilation into the fruit to fulfill cell metabolism requirements for oil synthesis. Conclusion The current findings indicated that two of four treatments, i.e. nano-N1K1 and N2K2, could be more effective on olive trees in terms of general fruit and oil attributes. It was remarkable that nano treatment with a lower concentration could provide adequate beneficial effects on quality characteristics of olive oil and is in line with good management strategies regarding the preservation of the environment. To the best of our knowledge, the current work is the first report considering the application of nano-chelated nitrogen and potassium and their is use as a foliar application on olive trees. Additional studies would be necessary to further optimize the concentration and timing of the applications with these new formulations.
Research Article
Growing vegetables
Leyla Cheheltanan; Saeid Khosravi; Seyyed Hossein Nemati
Abstract
IntroductionGrasses are narrow-leaved plants that are used as cover plants in landscape. These plants are one of the basic and necessary components of the green cover of most gardens, parks and as the background color of landscape. In Iran, due to the high costs of planting and management of grass, high ...
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IntroductionGrasses are narrow-leaved plants that are used as cover plants in landscape. These plants are one of the basic and necessary components of the green cover of most gardens, parks and as the background color of landscape. In Iran, due to the high costs of planting and management of grass, high water requirements, climatic incompatibility and damage to water and soil salinity, it is recommended to remove from the green space in some cities, especially in areas with low water and water and soil saline. If it is possible to benefit from the role and influence of these plants by observing the technical points and choosing the best species for each area. Salinity stress is the second limiting factor for the growth of plants in the world after drought, which affects the efficiency and performance of plants. Increase in salinity causes a decrease in the water potential in the soil. In this condition, the plant spends most of its energy to maintain the water potential, cell mass, and water absorption to have minimal growth. The aim of this research is the effect of external application of glycine betaine on the accumulation of osmolality compounds and the antioxidant system of sports grass under salt stress. Materials and MethodsThis research was done in factorial form in completely randomized design with 3 replications on Rashid variety cucumber. The factors included 4 levels of temperature (25, 30, 35 and 40 degrees Celsius) and 3 levels of salicylic acid (0, 0.5 and 1 mM). When the seedlings reached the two-leaf stage, they were sprayed with different concentrations of salicylic acid two times with an interval of five days. One week after the application of salicylic acid, temperature treatment was gradually applied. After applying each heat treatment, the corresponding pots were transferred to the greenhouse with a temperature of 25 degrees Celsius. Then, fresh and dry weight of root and shoot, leaf surface, chlorophyll index, electrolyte leakage, proline, polyphenol oxidase enzyme activity and superoxide dismutase enzyme activity were measured. Results and Discussion The results showed that salinity stress decreased all the study morphological, physiological and biochemical parameters including plant height, shoot fresh and dry weight, number of tiller, leaf area, chlorophyll content, protein and total antioxidant capacity in the studied plants. It also increased peroxidase enzyme, H2O2 and proline in plants, but glycine betaine application significantly improved the morpho-physiological characteristics of plants compared to the control under salt stress conditions. Thus, the highest height, shoot fresh and dry weight, leaf area, number of tiller, chlorophyll content, and protein and antioxidant capacity were observed in plants sprayed with glycine betaine. Also, the highest content of glycine betaine and activity of catalase and peroxidase enzymes and the lowest content of glycine betaine and H2O2 were observed in in plants sprayed with glycine betaine and 10 mM glycine betaine was more effective than 5 mM. The occurrence of salinity in plants disrupts the absorption of ions and causes the reduction of nutrients and increases sodium ions. One of the effects of salinity in plants is the reduction of photosynthetic activity, which results in the reduction of chlorophyll, carbon dioxide absorption, photosynthetic capacity, plant height, shoot fresh and dry weight, number of tiller and leaf area. One of the most strategies to deal with stress is accumulation of osmolyte and increasing the antioxidant activity, which makes plants resistant to environmental stresses. Salinity, through the toxic effect of Na+ and Cl- ions, affects the growth and performance of the plant by reducing the soil water potential, disrupting water absorption and imbalance of nutrients in the plant. The results obtained from comparing the average results of glycine betaine show that glycine betaine increased plant height, shoot fresh and dry weight, number of tiller, leaf area, chlorophyll content, total protein and antioxidant capacity, but on the other hand, it increased proline and H2O2 decreased, which is due to the accumulation of glycine betaine as a protector in plants under salt stress conditions. In stress conditions, glycine betaine can protect photosynthetic activities including photosynthetic enzymes, proteins and lipids in thylakoid membranes in the combination of photosystem II, and also the task of protecting cell membranes against osmotic stresses in the plant. ConclusionThe results obtained from this research showed that salinity stress reduced all the morphological, physiological and biochemical characteristics in the sport grass plants, but glycine betaine application played a positive role in reducing salinity damage and maintaining plant quality. Glycine betaine is known as one of the effective molecules in stress signaling, so it can protect the plant cells against stress by reducing the destruction of the membrane and by increasing the salt tolerance mechanisms. Also, glycine betaine 10 mM is introduced as the best treatment to reduce salinity damage in sport grass during present study.
Research Article
Pomology
Alireza Bonyanpour
Abstract
IntroductionPomegranate is a native fruit tree to Iran and has the best growth and performance in subtropical climate conditions. In recent years, due to environmental stresses conditions such as high temperature, high light intensity and low irrigation water a large number of orchards have faced to ...
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IntroductionPomegranate is a native fruit tree to Iran and has the best growth and performance in subtropical climate conditions. In recent years, due to environmental stresses conditions such as high temperature, high light intensity and low irrigation water a large number of orchards have faced to physiological problems such as fruit cracking, sunburn and a decrease in fruit quality. The high temperature along with high evaporation and transpiration can be considered as the main cause of these abnormalities, which causes disturbances in the process of plant metabolism and finally causes physiological disorders. Sunburn of the fruit is caused by high temperature and high sunlight intensity and has a negative effect on all the quality characteristics of the pomegranate fruit. Using net shade is one of the recommended ways to reduce the impact of climate change. Application of net shading in areas with high radiation levels has led to a decrease in the intensity of light radiation received by the canopy of the trees, which causes a decrease in the temperature of the leaf surface, and decrease the level of evaporation and transpiration in the trees. Materials and MethodsThis research was conducted during 2019-2020 for 2 years in a private orchard in the Kohmar area of Kazeron city of Iran. ́Rabab̕ pomegranate trees that were planted at a distance of 5 x 5 m and 15 years old were used. In this research, the effect of different types of net shading was investigated. The experiment was conducted as a randomized complete block design with 9 treatments and three replications in two years. The experimental treatments included the use of net shading in white and green colors with two different shading (30% and 50%) and two implementation methods (on the base and on the canopy of the tree) which were compared with control trees (without cover). During the growing season, measurements were made in relation to leaf temperature, sunlight intensity, soil moisture, relative water content of leaves, fresh and dry matter of leaves, and prolin content, and at the time of harvest, the percentage of sunburn, cracking and aril paleness of the fruit, thickness of fruit peel and anthocyanin content of fruit juice in all treatments were measured. Results and DiscusionsThe use of net shading increased the quantitative and qualitative characteristics of pomegranate fruits. The results of this research showed that the use of white and green nets 50% and green net 30% on the base had the best results. By using the appropriate type of net shading, the temperature of the pomegranate tree was reduced by about 6 degrees Celsius. Net shading also reduced the light intensity by at least 50%; the reduction of light intensity in green nets was more than in white nets.The highest relative water content was 85% in the green net shade (50% with base) treatment. Net shading significantly increased the water content of the leaves compared to the control.The use of net shading significantly reduced the percentage of sunburn on fruits compared to the control. Sunburn was about 14% in the control treatment and less than 5% in the net shading treatments. Net shading reduced the percentage of fruit cracking from 15 percent in the control treatment to about 7 percent in all shading treatments. ConclusionThe use of net shading as a cover for pomegranate trees reduces the temperature of the canopy of the plant by reducing the radiation of the sun, and by better maintaining the moisture of the soil of the pomegranate tree. It reduces the heat and drought stress condition and has a positive effect on the quantity and quality of the fruit produced. Among the treatments used, the use 3 types of net including 50% white nets on the base, and 30% and 50% green nets on the base had the best results. These treatments better than others in terms of shading percentage, temperature reduction, and improving the quantity and quality of pomegranate fruits . Net shading should be installed when the fruits are about 5 to 7 cm in diameter and will remain on the tree until mid-September. This type of tree shading did not leave any side effects on the quantity and quality of the fruits.
Research Article
Pomology
Esmaeil Khaleghi; Masumeh Zamani Dehbari; Norollah Moallemi
Abstract
IntroductionCitrus fruits are one of the most commercial fruit products in the world, whose growth and production are affected by abiotic stresses. Drought stress is one of the most important abiotic stresses that affects all the vital processes of the plant. One of the ways to moderate the negative ...
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IntroductionCitrus fruits are one of the most commercial fruit products in the world, whose growth and production are affected by abiotic stresses. Drought stress is one of the most important abiotic stresses that affects all the vital processes of the plant. One of the ways to moderate the negative effects of drought stress is the use of polyamines. Polyamines are a group of biochemical compounds that are used as one of the most effective compounds to resist environmental stresses. Polyamines have a wide role in various plant growth processes, such that they play a significant role in modulating various types of biotic and abiotic stresses. Studies have shown that application of putrescine increases the fresh and dry weight of the shoot and root parts, leaf relative water content, photosynthetic pigments, leaf surface, and photosynthesis in plants under drought stress. Materials and MethodsThis study was conducted to investigate the effect of different levels of putrescine (0, 0.5, 1 and 2 mM) and different levels of irrigation (100, 75 and 50% of evotranspiration potential) on morpho-physical traits of lime seedlings as a factorial experiment based on randomized complete block design with 3 replications.Two-year-old lime seedlings were obtained from a commercial nursery located in Dezful city (approved by the Khuzestan Agricultural Jihad Organization). Then, they were located in 15-kilogram pots and kept for 2 months in the greenhouse to adapting to the environmental conditions. In order to apply the irrigation regime, 4 pots were considered as reference plants and the amount of irrigation water was determined by weighing these pots. First, the weight of reference pots was calculated in field capacity mode. Then, after 7 days, the pots were weighed again and the difference between the primary and secondary weights was considered as the amount of irrigation water of 100% plant evaporation and transpiration, and according to that, 75% irrigation and 50% evaporation and transpiration potential were applied. The first foliar spraying with putrescine was done at first of March in Field capacity (foliar spraying was done once every month for 4 months from March to June). At the end of the experiment, the fresh and dry weight of root and shoot, number of leaves, relative water content, leaf water potential, photosynthesis, transpiration, stomatal conductance, were measured. Statistical data analysis was done using MSTATC software and, Duncan's multi-range test was used to mean comparation at the 5% probability level. Results and DiscussionResults showed that the rate of photosynthesis, stomatal conductance, relative water content of leaves, fresh and dry weight of aerial part and root decreased by reducing the amount of irrigation from 100 to 75 and 50%, of ETcrop. The reduction of growth parameters under drought stress can be due to the closing of the stomata and the reduction of carbon dioxide emission into the leaves, which can lead to lower levels of chlorophyll and photosynthesis, induction of oxidative stress, and finally less growth in plants. It has also been stated that the decrease in growth caused by drought stress in the initial stages of the stress can be due to the decrease in cell growth and development due to the decrease in turgor pressure and the decrease in the intensity of photosynthesis due to the closing of stomata. Also, the results showed that foliar spraying with 2 mM putrescine increased photosynthesis, stomatal conductance, relative water content of leaves, wet and dry weight of aerial parts and roots at all irrigation levels. The researchers believed that the increase in growth parameters, relative water content and photosynthetic pigments with putrescine foliar spraying can be related to the antioxidant properties of putrescine and its osmolality role in dry conditions. Other researches have shown that putrescine may modulate certain ion channels and increase the permeability of the membrane to calcium and cause a decrease in the entry of potassium into the membrane, which causes a decrease in the exit of water from the cell. Also, putrescine may increase leaf water potential and leaf content through osmotic regulation of the plant by increasing proline. ConclusionIn general, the results showed that foliar spraying of putrescine, especially at 2 mM concentration has the greatest effect on increasing growth parameters, including fresh and dry weight of shoots and roots, leaf area, increasing the relative water content, leaf water potential and Gas exchanges and reducing the amount of ion leakage under drought stress conditions.
Research Article
Growing vegetables
Saeed Mohammadzade; Morteza Goldani; Fatemeh Yaghobi; Mohammad Bannayan Aval
Abstract
IntroductionIncreasing the tolerance to drought and nitrogen stress in tomato cultivars is essential for the sustainable and environmentally friendly production of this product. Also, knowing the morpho-physiological, biochemical and molecular responses to drought and nitrogen stress is important for ...
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IntroductionIncreasing the tolerance to drought and nitrogen stress in tomato cultivars is essential for the sustainable and environmentally friendly production of this product. Also, knowing the morpho-physiological, biochemical and molecular responses to drought and nitrogen stress is important for a comprehensive understanding of plant water tolerance mechanisms and nitrogen limitation conditions in higher plants. Therefore, the purpose of this study was to investigate the effect of different levels of irrigation and nitrogen fertilizer on the quantitative and qualitative characteristics of tomatoes in different Cluster rows under greenhouse conditions. Materials and MethodsThe experiment was conducted at the research greenhouse of the Faculty of Agriculture, Ferdowsi University of Mashhad, in two years, 2021-02 and 2022-03. The experiment was set up as split-plot layout based on randomized complete block design with three replications. Irrigation levels were considered as the main plot at three levels: 75% (I75), 100% (I100), and 125% (I125) of the crop water requirement. Nitrogen fertilizer was considered as the subplot at four levels: control (no nitrogen), 75 kg ha-1 (7.5 g m-²), 150 kg ha-1 (15 g m-²), and 225 kg ha-1 (22.5 g m-²) from urea as the nitrogen source. Tomato seeds (Newton cultivar) were sown in polyethylene seedling trays with a coco peat and perlite mixture as the substrate. The seedlings were transplanted to the main field at 15 cm height with 3-4 true leaves. In all stages of growth, consistent agricultural practices were applied, including weed control, pest and disease management. Fertilization for tomato plants was based on soil analysis. Initially, after transplanting the seedlings, a complete fertilizer with high phosphorus (NPK 10-52-10) was applied at a ratio of 1.5 kg per thousand plants. In the subsequent stages, complete fertilizers (NPK 20-20-20) and high-potassium fertilizers (NPK 20-20-36) were applied through irrigation. Throughout the plant's growth stages, to prevent potential deficiencies and harm to growth and fruit development, micronutrients were applied as foliar sprays. Results and Discussion The results for all three Clusters showed that although nitrate accumulation was higher in the first year compared to the second year, in both years, nitrate accumulation was higher at I75 and 225 kg ha-1 nitrogen compared to the other treatments. The highest nitrate accumulation in the sixth (6.12 mg.kg-1) and seventh (6.29 mg.kg-1) Clusters was observed in I75 and 225 kg ha-1 nitrogen treatment in the first year. In the eighth Cluster, contrary to the sixth and seventh Clusters, the highest nitrate accumulation was obtained in I100 and 225 kg/ha nitrogen (6.43 mg.kg-1) in the first year. Chlorophyll decreased with stress but increased with nitrogen levels. In all four Clusters, the highest chlorophyll a content was obtained in I100 and 225 kg ha-1 nitrogen, with values of 3.75, 3.70, 3.30, and 3.85 mg g-1 fresh weight, respectively. The highest fruit number per square meter was obtained in I125 and 225 kg ha-1 nitrogen treatment in the second year (260 fruits), although there was no significant difference compared to the first year. Furthermore, this treatment produced 11% more fruits than the highest fruit number at 100% moisture. The highest single fruit weight was obtained in I125 and 225 kg ha-1 nitrogen treatment in the first year of the experiment (254 g), although there was no significant difference compared to the second year. Additionally, this treatment showed no significant difference in fruit weight compared to the 225 kg ha-1 nitrogen and I100 treatment in the first year but was 11% higher in the second year. The highest yield (65.1 kg m-²) was obtained at I125 and 225 kg ha-1 nitrogen. However, in the control treatment without fertilizer, there was no significant difference in yield at I100 and I125. Furthermore, the highest water use efficiency was observed at I100, followed by I75. In all fertilizer treatments, I125 treatment had the lowest water use efficiency. The highest water use efficiency (285 kg m-³) was obtained at I100 and 225 kg ha-1 nitrogen. Conclusion In general, the results demonstrated that while excessive nitrogen fertilizer increased nitrate accumulation at different irrigation levels, the increased use of irrigation water reduced nitrate accumulation in tomato fruits while improved yield. Moreover, no significant difference in fruit yield was observed between I125 and I100, but optimum yield and favorable water use efficiency were obtained with less water consumption. Based on the results of this experiment, the recommended treatment under greenhouse conditions is irrigation at 100% of the FC and the use of 250 kg ha-1 nitrogen.
Research Article
Ornamental plants
Meisam Mohammadi; Fatemeh Khosravifar; Negin Siahi
Abstract
IntroductionGrasses are narrow-leaved plants that are used as cover plants in landscape. These plants are one of the basic and necessary components of the green cover of most gardens, parks and as the background color of landscape. In Iran, due to the high costs of planting and management of grass, high ...
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IntroductionGrasses are narrow-leaved plants that are used as cover plants in landscape. These plants are one of the basic and necessary components of the green cover of most gardens, parks and as the background color of landscape. In Iran, due to the high costs of planting and management of grass, high water requirements, climatic incompatibility and damage to water and soil salinity, it is recommended to remove from the green space in some cities, especially in areas with low water and water and soil saline. If it is possible to benefit from the role and influence of these plants by observing the technical points and choosing the best species for each area. Salinity stress is the second limiting factor for the growth of plants in the world after drought, which affects the efficiency and performance of plants. Increase in salinity causes a decrease in the water potential in the soil. In this condition, the plant spends most of its energy to maintain the water potential, cell mass, and water absorption to have minimal growth. The aim of this research is the effect of external application of glycine betaine on the accumulation of osmolality compounds and the antioxidant system of sports grass under salt stress. Materials and Methods This research was carried out in 2022 in pots in the research greenhouse of Ilam University as a factorial based on a completely random design with three replications. Experimental treatments included three salinity levels with sodium chloride salt (without salinity, 50 and 100 mM sodium chloride) and three levels of glycine betaine foliar spraying (0, 5 and 10 mM). Glycine betaine application was performed after mowing twice with a distance of 48h from each other, and then salinity with sodium chloride salts was applied. 4 weeks after application of salinity stress, some morphological and biochemical characteristics of plants were measured. The results were analysed using SAS software (v.9.2), and Tukey's test was used to compare the means at the 5% probability level. Results and DiscussionThe results showed that salinity stress decreased all the study morphological, physiological and biochemical parameters including plant height, shoot fresh and dry weight, number of tiller, leaf area, chlorophyll content, protein and total antioxidant capacity in the studied plants. It also increased peroxidase enzyme, H2O2 and proline in plants, but glycine betaine application significantly improved the morpho-physiological characteristics of plants compared to the control under salt stress conditions. Thus, the highest height, shoot fresh and dry weight, leaf area, number of tiller, chlorophyll content, and protein and antioxidant capacity were observed in plants sprayed with glycine betaine. Also, the highest content of glycine betaine and activity of catalase and peroxidase enzymes and the lowest content of glycine betaine and H2O2 were observed in in plants sprayed with glycine betaine and 10 mM glycine betaine was more effective than 5 mM. The occurrence of salinity in plants disrupts the absorption of ions and causes the reduction of nutrients and increases sodium ions. One of the effects of salinity in plants is the reduction of photosynthetic activity, which results in the reduction of chlorophyll, carbon dioxide absorption, photosynthetic capacity, plant height, shoot fresh and dry weight, number of tiller and leaf area. One of the most strategies to deal with stress is accumulation of osmolyte and increasing the antioxidant activity, which makes plants resistant to environmental stresses. Salinity, through the toxic effect of Na+ and Cl- ions, affects the growth and performance of the plant by reducing the soil water potential, disrupting water absorption and imbalance of nutrients in the plant. The results obtained from comparing the average results of glycine betaine show that glycine betaine increased plant height, shoot fresh and dry weight, number of tiller, leaf area, chlorophyll content, total protein and antioxidant capacity, but on the other hand, it increased proline and H2O2 decreased, which is due to the accumulation of glycine betaine as a protector in plants under salt stress conditions. In stress conditions, glycine betaine can protect photosynthetic activities including photosynthetic enzymes, proteins and lipids in thylakoid membranes in the combination of photosystem II, and also the task of protecting cell membranes against osmotic stresses in the plant. ConclusionThe results obtained from this research showed that salinity stress reduced all the morphological, physiological and biochemical characteristics in the sport grass plants, but glycine betaine application played a positive role in reducing salinity damage and maintaining plant quality. Glycine betaine is known as one of the effective molecules in stress signaling, so it can protect the plant cells against stress by reducing the destruction of the membrane and by increasing the salt tolerance mechanisms. Also, glycine betaine 10 mM is introduced as the best treatment to reduce salinity damage in sport grass during present study.
