Mina Zahedi; Mehdi Sarcheshmehpour; Homayoun Farahmand
Abstract
Arbuscular mycorrhizal fungi (AMF) have a mutualistic relationship with a great number of plants. This can offer promising approaches to managing arid ecosystems. In the present study, the effects of native AMF inoculums were evaluated on morphological and physiological traits of Cercis siliquastrum ...
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Arbuscular mycorrhizal fungi (AMF) have a mutualistic relationship with a great number of plants. This can offer promising approaches to managing arid ecosystems. In the present study, the effects of native AMF inoculums were evaluated on morphological and physiological traits of Cercis siliquastrum and Prosopis cineraria seedlings under drought stress conditions. The study was carried out in two independent experiments as a full factorial design with two factors: AM fungal (non- AMF and AMF) and three levels of drought stress (80%, 50%, and 30% of field capacity). The results showed that shoot dry weight and root growth were reduced in response to an increase in drought stress levels on Prosopis cineraria. In C. siliquastrum, however, the shoot dry weight, root volume and root dry weight increased moderately as a result of AMF but decreased in response to severe drought stress. Native AMF inocula increased proline content by about two-fold, while also increasing root and shoot dry weight and root volume of the inoculated plants of both species. Drought stress increased proline content in both AMF plants and in uninoculated C. siliquastrum seedlings. The native AMF colonized the roots of C. siliquastrum and P. cineraria, by at least 80% and 70%, respectively, which was significantly higher than AMF from soils. Drought stress reduced catalase activity (CAT) in P. cineraria, but this was lower in inoculated plants than in uninoculated plants. In response to moderate and severe drought stress, ascorbic peroxidase (APX) activity increased by over 29 and 44%, respectively, compared to well-watered and inoculated P. cineraria seedlings. P. cineraria seedlings tolerated drought stress by both enzymatic and non-enzymatic ways, while C. siliquastrum accumulated osmotic solutes such as proline under drought stress. In conclusion, both species were recommended for xeriscaping purposes, although mesquite proved to be more reliable in adverse conditions.
Sahar Toupchizadeh Tabrizian; Jafar Hajilou; Sahebali Bolandnazar; Gholamreza Dehghan
Abstract
Strawberry is one of the most important commercial fruits. This research aimed to ameliorate the negative effects of water deficit stress using silicon application on strawberry. The experiment was conducted as a factorial in a completely randomized design with three factors including cultivar (‘Selva’ ...
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Strawberry is one of the most important commercial fruits. This research aimed to ameliorate the negative effects of water deficit stress using silicon application on strawberry. The experiment was conducted as a factorial in a completely randomized design with three factors including cultivar (‘Selva’ and ‘Gavioita’), Na2SiO3 (Sodium silicate) concentrations [0, 3, and 6 mM), as the source of silicon, and water deficit stress (40%, 60%, 80%, and 100% of field capacity (FC)], in three replications. ‘Gavioita’ cultivar showed the highest superoxide dismutase enzyme activity in leaves under sever water deficit stress (40% of FC) following Na2SiO3 (3 and 6 mM concentrations) application. Application of Na2SiO3 at concentration of 6 mM increased the catalase enzyme activity significantly in the leaves of ‘Gavioita’cultivar under severe water deficit stress (40% of FC). The activity of peroxidase enzyme was enhanced considerably under 80% of FC and lower water deficit in the fruits of both cultivars. The fruit total anthocyanin level was increased significantly by application of Na2SiO3 at 3 and 6 mM concentrations under water deficit stress (60% of FC). Also, Na2SiO3 (at concentrations of 3 and 6 mM) enhanced the proline level significantly in ‘Gavioita’ cultivar compared to the control treatment under normal conditions (100% of FC). In conclusion, the results of present study indicated that application of Na2SiO3 at 6 mM concentration is useful treatment to cope with sever water deficit stress (40% of FC) especially in ‘Gavioita’ cultivar of strawbery
Kobra Mahdavian
Abstract
Soil salinity is one of the critical challenges for development of culture area of agricultural crops. In the present study a pot experiment was conducted in factorial based on completely randomized design aimed to investigate the impact of exogenous application of salicylic acid (SA 0, 0.75 and 1.5 ...
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Soil salinity is one of the critical challenges for development of culture area of agricultural crops. In the present study a pot experiment was conducted in factorial based on completely randomized design aimed to investigate the impact of exogenous application of salicylic acid (SA 0, 0.75 and 1.5 mM) and calcium chloride (CaCl2 0, 50 and 100 mM), solely or in combination, on plant growth, photosynthetic pigments (total chlorophyll (Chl), carotenoids, anthocyanin), and some metabolic parameters (reducing sugars, proline, lipid peroxidation and scavenging ability on DPPH (2,2-diphenyl-1-picrylhydrazyl) radical) of red bean exposed to salt stress (0, 25 and 75 mM NaCl). Results showed that exogenous application of SA or calcium (Ca) alone improved plant performance under NaCl stress. Growth slowed down under salinity. Malondialdehyde (MDA), DPPH radical, anthocyanin, and proline content were increased under salinity stress. However, application of SA and Ca enhanced the growth parameters, improved the Chl, carotenoids, and reducing sugars content, and significantly reduced MDA and DPPH radical in plants. Therefore, induced tolerance to salinity as the result of SA and Ca application may be related to the regulation of antioxidative responses. Furthermore, the beneficial effect of SA and Ca were achieved by applications of 0.75 mM SA and 50 mM CaCl2, which are recommended to improve red bean performance under saline conditions. In conclusion, exogenous application of SA and Ca improved salinity stress tolerance through the regulation of antioxidant system.
Hassan Sarikhani; Mohammad-Sadegh Safariyan-Nejad
Abstract
One of the most important problems of strawberry cultivation in temperate regions is winter cold injuries. Current study investigated impacts of foliar application of glycine betaine (GB) at 0, 0.5, 1, 2 and 4 mM concentrations on the cold hardiness of strawberry. The plants were divided into two groups: ...
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One of the most important problems of strawberry cultivation in temperate regions is winter cold injuries. Current study investigated impacts of foliar application of glycine betaine (GB) at 0, 0.5, 1, 2 and 4 mM concentrations on the cold hardiness of strawberry. The plants were divided into two groups: one group for evaluation of cold hardiness at temperatures of -6, -9, -12, -15 and -18 °C; and the other for study of some biochemical characteristics. Results showed that GB treatment increased soluble carbohydrate and proline concentrations in both leaf and crown tissues, total protein concentration in leaf, and relative water content in leaf as compared to those in control. Based on LT50 calculated from electrolyte leakage and tetrazolium staining test, the GB application increased cold hardiness in strawberry plant based on its concentration. The highest cold hardiness was found in the 2 mM GB concentration based on electrolyte leakage and tetrazolium staining tests at -13.3 and -15.3 °C. Meanwhile, the lowest values of cold hardiness were observed in the control treatments based on electrolyte leakage and tetrazolium staining tests at -10.2 and -11.0 °C. Significant correlations were found between soluble carbohydrate and proline concentrations in leaf and crown, and total protein concentration with LT50 calculated from electrolyte leakage and tetrazolium staining test. We conclude that application of 2 mM GBhas the capacity to increase the freezing tolerance of strawberry and could be used as a prophylactic tool to reduce winter cold injury.
Fatemeh Nasibi; Khosrow Manouchehri Kalantari; Zahra Manzari Tavakoli
Abstract
One of the major abiotic stresses limiting the productivity and the geographical distribution of many important crops is low temperature. Hydrogen sulfide (H2S) is an important signaling molecule involved in several stress-resistance processes such as drought, salinity and heavy metal stresses in plants. ...
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One of the major abiotic stresses limiting the productivity and the geographical distribution of many important crops is low temperature. Hydrogen sulfide (H2S) is an important signaling molecule involved in several stress-resistance processes such as drought, salinity and heavy metal stresses in plants. The aim of this study was to investigate the effects of exogenous H2S on improving chilling tolerance of cucumber seedlings. The results indicated that seedlings exposed to chilling stress (4 ºC) increased the level of electrolyte leakage, lipid peroxidation, hydrogen peroxide, proline content and guaiacol peroxidase (GPX) activity; while sugar soluble content decreased. Pretreatment with sodium hydrosulfide (NaHS), a hydrogen sulfide donor, slightly reduced the malondialdehyde content, hydrogen peroxide content and electrolyte leakage, which were induced by chilling stress and also elevated the activity of antioxidant enzymes, soluble sugar and proline levels, and reduced glutathione content in plants under chilling stress condition. Pre-treatment with other Na+ and sulfur-containing components including Na2S, Na2SO4, Na2SO3 showed no significant effect on lipid peroxidation and hydrogen peroxide content under chilling stress. It can be concluded that the effect of NaHS pretreatment on alleviation of cold stress damages is probably related to its ability to release H2S because Na+- or sulfur-containing compounds (except NaHS) had no similar effects on alleviation of chilling damages.
Majid Rahemi; Fateme Yazdani; Sahar Sedaghat
Abstract
Selection of frost tolerant cultivars and understanding the mechanisms of frost hardiness could help to improve freezing resistance in olive plants. Olive cultivars may differ in frost hardiness due to differential survival of specific organs. The aim of this study was to screen different olive cultivars ...
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Selection of frost tolerant cultivars and understanding the mechanisms of frost hardiness could help to improve freezing resistance in olive plants. Olive cultivars may differ in frost hardiness due to differential survival of specific organs. The aim of this study was to screen different olive cultivars based on their stomatal density and metabolic modifications under cold conditions. The ‘Zard’ cultivar had the lowest while ‘Derak’ had the highest stomatal density, respectively. In another experiment, where entire potted olive plants were subjected to freezing stress (0, -6, -12 and -18 ˚C), ‘Zard’ and ‘Dehghan’ were found to be the most tolerant cultivars. They showed the lowest starch content, ionic leakage and wood injury. They also had the highest reducing sugar, phenolic and proline contents among studied cultivars. We concluded that ‘Zard’ and ‘Dehghan’ are the most tolerant cultivars and ‘Derak’, ‘Dakal’ and ‘Shiraz’ are the most sensitive cultivars to freezing injury.
Taher Barzegar; Pouria Moradi; Jaefar Nikbakht; Zahra Ghahremani
Abstract
To investigate effects of putrescine (Put) and humic acid (HA) on fruit yield and physiological attributes of okra (Abelmoschus esculentus L. 'Kano') under water deficit stress, a field experiment was conducted in split plot based on a randomized complete block design with three replications. Plants ...
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To investigate effects of putrescine (Put) and humic acid (HA) on fruit yield and physiological attributes of okra (Abelmoschus esculentus L. 'Kano') under water deficit stress, a field experiment was conducted in split plot based on a randomized complete block design with three replications. Plants were exposed to three different irrigation regimes (33%, 66% and 100% ETc) and were treated with foliar application of Put (0, 0.5, 1 and 1.5 mM) and HA (0, 150 and 300 mg l-1). The results showed that deficit irrigation significantly decreased fruit yield, relative water content (RWC), vitamin C and water use efficiency (WUE), whereas proline content and catalase and peroxidase activities were increased. Foliar application of HA and Put significantly increased fruit yield, RWC, vitamin C and proline contents, catalase and peroxidase activities and WUE. The results suggested that HA at 300 mg l-1 and Put at 1.5 mM can improve growth, yield and quality of okra fruits.
Mohammad Hosein Shamshiri; Mohammad Reza Hasani
Abstract
This study was conducted to determine the combined effects of salicylic acid (SA) and arbuscular mycorrhizal fungi (AMF) (Glomus mosseae) symbiosis on the growth of pistachio seedlings (Pistacia vera ‘Abareqi’) grown in the greenhouse under different drought stress (DS) levels. The arbuscular ...
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This study was conducted to determine the combined effects of salicylic acid (SA) and arbuscular mycorrhizal fungi (AMF) (Glomus mosseae) symbiosis on the growth of pistachio seedlings (Pistacia vera ‘Abareqi’) grown in the greenhouse under different drought stress (DS) levels. The arbuscular mycorrhizal fungi (AMF) colonization or exogenous SA treatment could increase ‘Abareqi’ pistachio seedlings tolerance to DS. Application of SA on AMF-inoculated seedlings further promoted drought tolerance, as indicated by an alleviated plant biomass and water relations compared to the respective treatments. The analysis of proline and soluble carbohydrates showed that the increased drought tolerance in the treated plants may be associated, at least in part, with increasing of proline accumulation in the leaves of stressed plants.
Ali Akbar Ghasemi Soluklui; Ahmad Ershadi; Zia eldin Tabatabaee; Esmaeil Fallahi
Abstract
Freezing injury is an important limiting factor in the production of pomegranate in Iran.The aim of the present study was to evaluate the effect of paclobutrazol (PBZ) on cold hardiness of pomegranate (Punica granatum L.) cv. ‘Malas Saveh’. Different concentrations of PBZ including 0 (control), ...
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Freezing injury is an important limiting factor in the production of pomegranate in Iran.The aim of the present study was to evaluate the effect of paclobutrazol (PBZ) on cold hardiness of pomegranate (Punica granatum L.) cv. ‘Malas Saveh’. Different concentrations of PBZ including 0 (control), 31, 62, 125 or 250 mg L–1 were sprayed on one-year-old plants in August and the electrolyte leakage of their stems was measured at three acclimation stages (November, January, and March). PBZ treatments, especially at 125 and 250 mg L–1 concentrations increased cold hardiness, and corresponding soluble carbohydrates and proline contents. The highest variation in freezing tolerance was observed between control and PBZ-treated plants in January, and the lowest found in November. Irrespective of PBZ treatment, correlations between cold hardiness and soluble carbohydrate concentrations were stronger, compared to proline. Soluble carbohydrates were higher in January, associated with deep dormancy, whereas the maximum proline content was detected in March, at deacclimation stage. Results suggest that PBZ application can reduce low temperature-induced dysfunction of cell membrane through increasing soluble carbohydrates and proline contents.
