Breeding plants for stress conditions
Hossein Nazary; Mozaffar Roostaei; Seid Mohammad Alavi Siney
Abstract
IntroductionDrought is one of the major limitation on food production worldwide (Hu et al., 2020), which is a growing problem caused by an increasing world population. In wheat cultivation in the Mediterranean climate, mainly the stages of flowering and grain filling are exposed with drought stress. ...
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IntroductionDrought is one of the major limitation on food production worldwide (Hu et al., 2020), which is a growing problem caused by an increasing world population. In wheat cultivation in the Mediterranean climate, mainly the stages of flowering and grain filling are exposed with drought stress. Drought stress reduces the yield of wheat in all growth stages, but its negative effect on grain yield is very severe in the stages of flowering and grain filling. Terminal drought and moisture stress are the main factors of wheat yield reduction under rainfed condition compared to irrigation conditions in Iran. Therefore, one solution to increase the yield is the breeding under drought stress conditions. Due to the low heritability of yield and the complex mechanisms of drought tolerance, little progress has been made in wheat grain yield under drought conditions. Therefore, the grain yield of wheat should be improved indirectly through improving the traits that greatly affect grain yield. Therefore, it seems necessary to identify the quantity and quality of relationships between different traits and grain yield under rainfed conditions. The use of multivariate statistical methods such as path analysis and canonical correlation analysis can help to identify important and effective traits in determining seed yield. This research was carried out with the aim of finding effective agronomical traits on yield and investigating the relationship between these traits and physiological traits under rainfed conditions.Materials and methodsIn order to determine the effective trait on wheat grain yield under rainfed conditions and investigate the relationship between agronomic and physiological traits, an experiment was conducted with 21 lines along with Baran, Hashtroud and Sardari cultivars as control in the form of a randomized complete blocks design in four replications during two years at Khodabande Rainfed Research Station. Plant height (PLH), Day to Heading (DHE), Day to physiological maturity (DMA) at the same time as peduncle yellowing, 1000 grain weight and yield after physiological maturity were measured. To determine the variability between the studied genotypes, descriptive parameters and compound variance analysis were performed based on the expected of mean square, the effects of year and replication was randomly considered and the effect of genotype as a fixed effect using SAS (9.4) software. Simple correlation analysis, path analysis and canonical correlation analysis were used to determine the relationship between traits and to determine effective traits.Results and discussionANOVA showed significant difference between genotypes in terms of all studied traits. Simple correlation analysis showed 19 significant correlation and other correlation were not significant. There is a positive and significant correlation between grain yield and Photosynthesis rate, height and 1000-grain weight, but the relationship between day to heading and grain yield was negative and significant. Path analysis revealed that day-to-heading and day-to-maturity traits with -1.05 and 0.84 had the most direct and negative direct effects on grain yield, respectively. Canonical correlation analysis also showed a significant canonical correlation (r = 0.74) between the set of physiological traits and agronomic traits. According to the results of this study, it was found that agronomic traits of day to heading, day to maturity and height are effective in determining grain yield under dryland conditions.ConclusionThe investigation of the relationship between traits also showed that selection for physiological traits such as transpiration rate and lower stomatal conductance led to selection of genotypes with high height, low day to heading and shorter growth period and finally higher yield under rainfed conditions.Therefore, genotypes with shorter growth periods that can escape terminal-season stresses and lose less water by closing stomata are suitable for high yields under rainfed conditions.
Biotechnology and environmental stresses
Shahrbano Abootalebi; Nasser Zare; Parisa Sheikhzadeh Mosadegh
Abstract
IntroductionTranscriptomics studies speed up the basic and applied research on the identification of genes involved in the biosynthesis of medicinally significant primary and secondary metabolites as well as plant responses to biotic and abiotic stresses. The adequate quality and quantity of RNA are ...
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IntroductionTranscriptomics studies speed up the basic and applied research on the identification of genes involved in the biosynthesis of medicinally significant primary and secondary metabolites as well as plant responses to biotic and abiotic stresses. The adequate quality and quantity of RNA are essential for successful transcriptomics investigations such as RNA sequencing (RNA-seq) and microarrays. It is extremely difficult to isolate RNA from medicinal plants with high levels of polyphenols and polysaccharides, such as Borago officinalis. Moreover, isolating nucleic acids from tissues exposed to stressful conditions of heavy metal toxicity such as cadmium is challenging due to the increased accumulation of reactive oxygen species (ROS) and secondary metabolites. Any RNA-seq experiment requires high-quality RNA because the isolated RNA should meet stringent quality control requirements in order to be sequenced on the various platforms. In the present study, we evaluated different RNA extraction methods to obtain an efficient protocol for isolating high-quality total RNA from borage tissue exposed to cadmium stress.Materials and methodsThe borage seedlings were grown in hydroponic containers containing half-strength Hoagland's nutrient solution in a growth chamber. Borage seedlings were exposed to 162 μM Cd using cadmium nitrate (Cd (NO3)2.4H2O) at 5-6 leaves stage and sampled at 48 h after treatment. The roots and leaves were subjected to five RNA isolation methods, including phenol/chloroform-based method, CTAB-based method, SDS-based method, RNX-plus protocol, and modified RNX-plus method to obtain an efficient protocol for isolating high-quality total RNA. The concentration and purity of the RNAs extracted using the abovementioned protocols were determined using gel electrophoresis and NanoDrop spectrophotometer. The quality and integrity of selected total RNA were approved with cDNA synthesis, RT-PCR, Bioanalyzer System, and transcriptome sequencing. After evaluating the extraction methods, a quick, simple and efficient instruction based on the modified RNX-Plus extraction method was afforded.Results and discussionThe results showed that the modified RNX-plus method was a fast and efficient protocol for the isolation of RNA from the borage leaf and root when compared with other methods. The method overcame the limitations posed by poor quality and low concentration of isolated RNA from borage samples exposed to cadmium stress. The A260/A280 and A260/A230 ratios of the RNA extracted using the modified RNX-plus method were 2.1 and 2.07, respectively, revealing its high purity. The key factors in the optimized protocol that resulted in removing the impurities were included the increasing ratio of extraction buffer to the amount of the powdered plant sample, using the optimized volume of chloroform, raising the RNA precipitation time at -20°C, washing RNA with lithium chloride and washing again with ethanol. Also, the yields of 333±15 and 463±43 ng μl-1 of RNA with RNA integrity (RIN) numbers of 8.6 and 9.05 were obtained from roots under cadmium stress and control conditions using the described optimized method, respectively.ConclusionIn general, the results of this study showed that the modified RNX-Plus method is convenient, fast, and effective for the isolation of total RNA from borage root and leaf tissues that contain different levels of polysaccharides, polyphenols, and secondary metabolites, and no solution is needed to be prepared before, except for ethanol and Lithium chloride. Since the RNA extracted from this procedure was successfully used for cDNA library construction, RT-PCR, and RNA sequencing, it can be considered as a simple and efficient method for the isolation of RNA from medicinal plants.
Drought stress
Somayeh Miri; Yaser Alizade; Hamzeali Alizadeh; Ekhlas Amini
Abstract
IntroductionUnder water stress conditions, intercropping can be used as a strategy for maximum use of sunlight and limited water resources. Due to the difference in morphological and physiological traits, the two plants corn and mung bean may be suitable for intercropping under drought stress; Therefore, ...
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IntroductionUnder water stress conditions, intercropping can be used as a strategy for maximum use of sunlight and limited water resources. Due to the difference in morphological and physiological traits, the two plants corn and mung bean may be suitable for intercropping under drought stress; Therefore, this research was conducted with the aim of investigating the effects of drought stress on the physiological traits and yield of corn and mung beans in monocultures and intercropping in order to study the possibility of reducing water consumption in this production system.Materials and methodsAn experiment was carried out as a split plot based on randomized complete block design with three replications at Ilam University during 2019-2020 growing season. The main plot were four water regimes including (40, 60, 80, and 100% of the plant's water requirement) and the subplots were include the planting pattern at four levels (additive intercropping series 100% corn + 50% mung bean, replacement intercropping series 50% corn + 50% mung bean and monocultures of mung bean and corn). The application of drought stress started after the establishment stage of the plant and continued until the harvest. At the end of the growth period, some physiological traits of both plants were measured, including photosynthetic pigments, photosynthesis rate, transpiration rate, intercellular CO2 concentration, proline amount, leaf relative water content and grain yield. Finally, analysis of variance (ANOVA) was performed using Minitab 14 and SAS 9.1 softwares and the means compared by HSD test at 5% probability level (p≤0.05).Results and discussionThe results showed the highest rate of photosynthesis (25.4 µmol CO2.m-2.s-1) was obtained in the treatment of 100% water requirement and the lowest rate of photosynthesis was obtained in 40% water requirement, which showed a decrease of 68.5% compared to the well-watered conditions. The rate of photosynthesis of corn in the replacement intercropping of 50% corn + 50% mung bean was 18.3% higher compared to monocultures corn. The highest rate of mung bean photosynthesis was observed in replacement intercropping under conditions of 100% water requirement and additive intercropping series under 80% water requirement, and the lowest rate of mung bean photosynthesis was observed in intercropping under conditions of 60 and 40% water requirement. Dehydration stress decreased the amount of total chlorophyll in mung beans and corn. The highest intercellular CO2 concentration (475.5 mmol of CO2.m-2.s-1) and the temperature of the corn leaf (36.7 °C) belonged to the 40% water requirement treatment. The rate of transpiration of corn and mung bean decreased by 55.56 and 61.43% in the condition of 40% water requirement compared to well-watered conditions. Water stress reduced the relative water content of corn and mung bean. The highest proline in corn and mung leaves (46.3 and 45.23 µmol.g-1.FW-1, respectively) was obtained in the treatment of 40% water requirement, which had no significant difference with 60% water requirement. Corn grain yield in the treatment of 40% water requirement showed a decrease of 52.76% compared to 100% water requirement. Monocultures (3945.8 kg.ha-1) and intercropping (3875.1 kg.ha-1) had the highest corn grain yield, and the lowest corn grain yield in replacement intercropping was 2700 kg ha-1. At all irrigation levels, the highest grain yield of mung bean was obtained in monocultures, and the yield decreased in additive and replacement intercropping, and additive intercropping had the lowest grain yield. The values of land equality ratio of all intercropping patterns were greater than one, which indicates the advantage of corn and mung bean intercropping patterns to use land and increase yield.ConclusionConsidering the occurrence of recent droughts in arid and semi-arid regions of the country and the need for forage in these regions, the cultivation of forage plants, especially corn, is inevitable. Therefore, one of the appropriate strategies to protection in management and water consumption is the intercropping of this plant with plants of the legume such as mung bean. Intercropping can partially moderate the effects of drought stress on plant water conditions. In general, it seems that the patterns of intercropping and substitution, due to having higher grain yield potential, is a suitable strategy for producing higher yield and stability of this plant compared to monocultural under well-watered and stress water.AcknowledgmentsThis research has been carried out using the research credits of Ilam University, by which we express our thanks and appreciation to the respected Assistance of Research and Technology of Ilam University.
Physiology of crops under stress conditions
Ramin Lotfi
Abstract
IntroductionPlants in the environment are affected by various stresses, depending on the duration, intensity and growth stage of the plant, these stresses can reduce the process of photosynthesis and affect their growth and performance. However, traditional methods, even technically advanced ones such ...
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IntroductionPlants in the environment are affected by various stresses, depending on the duration, intensity and growth stage of the plant, these stresses can reduce the process of photosynthesis and affect their growth and performance. However, traditional methods, even technically advanced ones such as the measurements of photosynthetic rates through the gas exchange (CO2, H2O, and O2), are time-consuming and provide incomplete information on overall photosynthetic function. The development of knowledge in the field of chlorophyll fluorescence shows that this indicator has a high ability to study the photochemical efficiency of plant photosynthesis.MethodsFor measuring the chlorophyll fluorescence in plants, leaves were dark-adapted for 30 minutes using leaf clips provided by the producer of handy-PEA. Measurements were performed on the middle of plant leaves following the standard protocol with illumination with continuous red light (peak in 650 nm wavelength; the spectral line half-width of 22 nm) provided by an array of three light-emitting diodes. The light pulse intensity used was 3500 μmol(photon).m–2s–1 and the duration of the light pulse was 1 s. The measured data were used for the calculation of the photosynthetic parameters using Biolyzer v. 3.06 HP software (a software provided with handy-PEA). Some of the parameters we discussed in this article due to their significance are FO = minimum fluorescence, FM = maximum fluorescence, FO/FM = The maximum quantum yield of basal non-photochemical energy losses, FV/FM = the maximum quantum efficiency of PSII, VJ = the relative variable fluorescence in step J after 2 ms, VI = the relative variable fluorescence in step I after 30 ms, N = the number of QA redox turnovers until FM, SM = the pool size of the electron acceptors on the reducing side of PSII, PIABS = performance index.Main FindingsThe study of chlorophyll fluorescence can analyze with high detail the function and state of PSII reaction centres, and light-harvesting complexes. This index has a high correlation with other physiological parameters under different environmental stresses. In this article, an overview of the results of chlorophyll fluorescence analysis of crops underenvironmental stressesis given, and the key steps to stresses are presented. Under drought stress the ratio of active reaction centers in chlorophyll, primary photochemical reactions, and electron transfer are affected. By salinity stress in crops, the values of variable and, maximum fluorescence, the energy required to close the reaction centers, and the photosynthetic efficiency index decrease, while the time required to reach the maximum fluorescence increases. Under cold stress conditions, electron transfer flow per reactive centers, the quantum performance of photosystem II, and the efficiency of the water splitting complex in photosystem II decrease. Potassium affects light-dependent steps such as the size of receiving antennae and the electron connection of photosystem II reaction centers. The electron acceptor part of photosystem II is the main site of inhibition of photosynthetic electron transfer under the application of herbicides.Conclusion and ImplicationsThis article has provided an overview of the information about the wide opportunities of using the chlorophyll fluorescence technique in plant science, agriculture and ecological research. The measured parameters of chlorophyll fluorescence are called the JIP-test and its analysis can be used to evaluate the effects of environmental stresses on plants. This technique requires more practical studies in biotic and even non-biotic stress conditions to provide reliable information to investigate the growth and development of plants, and this leads to an increase in our knowledge of the physiological basis of crop photosynthesis under stress conditions.
Salinity stress
Shakiba Shahmoradi; Azita Nakhei; Seyed Ali Tabatabaie
Abstract
IntroductionThe combination of the effects of drought stress and soil salinity causes a severe limitation in the production of agricultural crops. Irrigation with saline water has caused the expansion of more saline lands. Salt tolerant genotypes are very important in the development of agricultural ...
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IntroductionThe combination of the effects of drought stress and soil salinity causes a severe limitation in the production of agricultural crops. Irrigation with saline water has caused the expansion of more saline lands. Salt tolerant genotypes are very important in the development of agricultural systems suitable for saline lands. Soil salinity through soil amendment and or the cultivation of tolerant crops can be adjusted. Of course, soil amendment is a costly process and the cultivation of tolerant species and varieties is the most practical solution in conditions where soil salinity is low. It is clear that the genotypes show a significant difference in response to salinity stress. One of the ways to deal with salinity is to select and find salinity-tolerant cultivars through the use of breeding methods. It is also possible to select and modify salinity-tolerant species in some fodder plants of temperate regions. This research was modified, with the aim of evaluation of selected barley genotypes from past years' experiments, under salinity stress conditions and identification and introduction of tolerant genotypes and direct and indirect use of them in breeding programs.Materials and methodsIn this experiment, the genotypes were evaluated during two crop years in the form of a rectangular lattice design with three replications at the research station of South Khorasan Agriculture and Natural Resources Research Center, Birjand. The experiment was conducted under normal conditions and salt stress separately. In order to compare these genotypes with modified cultivars, six cultivated barley cultivars, including two salinity-tolerant controls, including Mehr and Khatam cultivars and the semi-sensitive Yusuf control, were also included in the experiments (Table 1). In addition to evaluating the phenological traits of days to flowering and days to maturity, the traits of plant height, seed yield, and 1,000-seed weight were recorded. Stress indices including stress tolerance index (STI) were calculated based on grain yield in barley genotypes.Results and discussionThe combined analysis of phenological, morphological and agronomic traits in the evaluated genotypes in two cropping years and two normal conditions and salinity stress showed that the interaction effect of year, salinity stress and genotype on the traits is significant. This showed that the reaction of genotypes was different in different years and different salinity conditions, so the results in different years were analyzed separately. In the salt research station in the first year of the experiment, genotypes number 31 (TN4006), 30 (TN3947), 50 (TN5008) and 28 (TN3646) along with Yusuf, Nusrat and Gohran cultivars, in terms of agronomic traits and stress indices were superior. While in the second year, the top genotypes were genotypes No. 44 (TN4904), 25 (TN3477), 23 (TN3470) and 32 (TN4104) along with Nimroz and Mehr cultivars.ConclusionThe information related to the trend of temperature changes and rainfall in different months in Birjand showed that the amount of rainfall was significantly higher in the first year of the experiment. In addition to reducing the salinity of the soil by adjusting the temperature, it reduces the amount of evaporation and transpiration and the intensity of the salinity stress. Therefore, it seems that the level of salinity stress was milder in the first year and more intense in the second year, and this was also observed in the stress intensity index. Based on this, the difference in the results in the two years of the experiment can be justified, in other words, in the first year, tolerant genotypes were introduced in mild stress and in the second year, tolerant genotypes were introduced in severe stress. Overall, these results showed that climate changes in different years have a great impact on the response of genotypes to salinity stress.
Drought stress
Zeynab Tamasoki; Babak Andalibi; Sajjad Nasiri
Abstract
IntroductionWater shortage has become a global problem and has caused many problems in agriculture and food supply for the growing world. Barley (Hordeum vulgare L.) as the fourth mostly-cultivated cereal, is one of the most strategic crop plants which is produced almost all over the world as a source ...
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IntroductionWater shortage has become a global problem and has caused many problems in agriculture and food supply for the growing world. Barley (Hordeum vulgare L.) as the fourth mostly-cultivated cereal, is one of the most strategic crop plants which is produced almost all over the world as a source of and important staple food and animal feed (Thabet et al., 2020). Food uncertainty is a comprehensive obstacle becomes more serious hazard all over the world in particular in developing countries for the sake of overpopulation and dwindling accessibility of croplands, water and other resources related to agricultural scopes. Water scarcity, results in plenty of disturbances in plant functions like cell division and elongation, water and nutrients relations, photosynthesis, enzymes activity, stomata movement, assimilate partitioning, respiration, oxidative damage, growth, and productivity, as several types of researches show that water shortage in the soil cause many disorders in plant tissues, which in turn leads to a punctual diminish in the photosynthesis rate (Todorova et al., 2022). In such a trouble circumstances, most of the plants are not capable to absorb abundant water, which is required for optimized growth (Danish et al., 2020).Materials and methodsTo investigate the impact of different irrigation regimes as well as foliar application of methyl jasmonate on growh, physiological and biochemical characteristics of barley varieties, an experimental research using factorial split plot design in 3 replications was carried out in experimental farm of the faculty of agriculture at the University of Zanjan in 2021-2022 cultivation season. In this experiment, irrigation regimes as the main factor, including complete irrigation as the control, withholding water in flowering stage, withholding water in grain filling period and complete dry farming, varieties as the secondary factor including Bahman, Sahand, Jolgeh, Abidar as well as Ansar, and foliar application of methyl jasmonate including without spraying (control) and spraying 50 μmol of methyl jasmonate were investigated. Results showed that the effect of irrigation regime had significant impact on almost all of the characteristics except chlorophyll a/b.Results and discussionVarieties showed considerable difference from the aspect of height, concentration of soluble sugar and grain yield. Effect of Methyl jasmonate on the relative water content (RWC), photosynthetic pigments, soluble sugar content, proline content, Malondialdehyde (MDA) and grain yield was significant. The highest grain yield (4762 kg ha-1) was detected when variety of Jolgeh was irrigated normally and was sprayed by 50 μmol of Methyl jasmonate and the lowest grain yield (432 kg ha-1) was seen when variety of Bahman was dry-farmed without foliar application of methyl jasmonate.ConclusionThe current study illustrated that barley can be grown in drought stress conditions if the right management is set on its cultivation. Methyl jasmonate showed a significant impact on the growth characteristics, biochemical and physiological attributes of the barley, despite the fact that drought had substantial adverse effects on the studied parameters of barley. However, drought resulted in different properties in barley varieties.
Heavy metals
Elham Jam; Saeid Khomari; Ali Ebadi; Esmaeil Goli Kalanpa; Akbar Ghavidel
Abstract
IntroductionHeavy metal contamination in soil refers to the excessive accumulation of elements called heavy metals, which are capable of causing significant levels of biological toxicity. These metals, in concentrations higher than of tolerable threshold of plants, often cause metabolic disorders, inhibition ...
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IntroductionHeavy metal contamination in soil refers to the excessive accumulation of elements called heavy metals, which are capable of causing significant levels of biological toxicity. These metals, in concentrations higher than of tolerable threshold of plants, often cause metabolic disorders, inhibition of growth and physiological process and eventually lead to death of plants. Lead (Pb) and zinc (Zn), as the two common coexisting mineral heavy metals around the world, accumulate in the soil due to mining activity and can adversely affect the crop productivity, the agro-ecosystem components and ultimately the human and environmental health. Biochar, as a potent soil amendment agent, is often obtained by pyrolysis of agricultural organic wastes such as crop residues under low oxygen pressure condition. Trichoderma harzianum, as a plant growth promoter, has capability in stimulating plant growth under varying environmental stresses and therefore, inoculation of plant roots with this fungus could be a conceivable approach to cope with the heavy metal stress. Hairy vetch (Vicia villosa Roth) is a winter annual forage species that shows better growth performance than the other forage legumes such as alfalfa or clover under the severe environmental conditions, especially winter frost and drought.phosphorus supplementation and their interactions on the growth, physiology and P, Pb and Zn uptake by hairy vetch in heavy metal-polluted soil.Materials and methodsThe experiment was carried out in the greenhouse of Faculty of Agriculture and Natural Resources of Mohaghegh Ardabili University as a factorial experiment based on a completely randomized design (CRD) in three replications. Heavy metal contaminated soil was collected from wheat fields around Angouran village (Angouran Rural District, Angouran District, Mahneshan County, Zanjan Province, Iran), downstream of the Zanjan's lead and zinc processing plant (Calcimin® Co.; 36°34'13.2"N 47°37'21.4"E), from a depth of about 0 to 25 cm. Two levels of biochar application (non-biochar control, 5% peanut hull-derived biochar), two levels of Trichoderma inoculation (non-inoculation control and inoculation with conidial suspension) and three levels of P supplementation (0P, non-supplementation; 11P, 11 mg P.kg-1 and 22P, 22 mg P.kg-1) were applied as the three experimental factors. The feedstock of peanut hull (PH) used in the present experiment were purchased from the local market. After thorough washing, PHs were air-dried and then well ground with a lab-scale mill and sieved using a 100 mesh sieve size. T. harzianum Rifai - T22 isolate acquired from the Laboratory of Plant Pathology, Faculty of Agriculture and Natural Resources, University of Mohaghegh Ardabili was revived on PDA (potato dextrose agar) medium and further incubated for at least one week at 28 °C. This experiment was conducted in an open-air vegetation yard with mean day/night temperatures of 25/17 °C, respectively. The experiment lasted for 50 days, in the period from May 16, 2020 (sowing the seeds) until July 5, 2020 (final sampling). In each plastic pot (25 cm in diameter × 20 cm in height), pre-filled with the pot mixture according to the treatments, 20 surface-sterilized hairy vetch (Vicia villosa Roth., Local landrace from Ardabil, Iran) seeds were sown and irrigated with tap water (EC = 0.21 dS m-1 and pH = 7.2) to 100% field capacity. Throughout the experiment, all the pots were re-irrigated when the soil water content dropped to 70% of the field capacity.Results and discussionApplication of biochar and Trichoderma fungus at not using phosphorus (P0), resulted in higher aerial biomass. Trichoderma fungus alone or with P11 level had a better result in increasing plant height. The concentration of chlorophyll a was in highest level by biochar combined Trichoderma, and P0 phosphorus applied, as well as the application of Trichoderma caused the highest concentration of chlorophyll b. The changes in relative leaf water content ranged from 85.5 to 90.5% among the treatment combinations. Phosphorus consumption at the maximum level (P22) showed the same effect in improving leaf protein compared to the P0 level. Moderate phosphorus consumption (P11) combined with biochar and Trichoderma caused the highest soluble sugar content. The highest proline content of leaves was obtained by using Trichoderma without applying biochar and phosphorus. The use of biochar alone or with Trichoderma could improve the amount of phosphorus absorption as much as the use of phosphorus fertilizer alone. Combined application of biochar and Trichoderma fungus with P11 and P22 fertilizer levels increased phosphorus absorption by 41.6% and 22.3% respectively compared to P0 level. Trichoderma fungus had no significant effect on the amount of Pb and Zn absorption in the aerial parts, but biochar significantly reduced their absorption in the aerial parts of Hairy vetch plants.ConclusionBased on the results, the application of biochar alone or in combination with Trichoderma fungus improved the vegetative traits and physiological characteristics, including increasing the concentration of photosynthetic pigments, the relative content of leaf water and soluble sugar, the content of protein and proline in the cluster flower vetch. Phosphorus absorption increased significantly when using biochar and Trichoderma. It seems that biochar helps to increase photosynthesis by creating suitable conditions in soil porosity, humidity, increasing cation exchange capacity and reducing the concentration of heavy elements, with better absorption of elements and thus improving plant growth and development. Trichoderma fungus with biological control increases the availability of elements including phosphorus by increasing the transfer of sugar and amino acids and creating induction resistance and stimulating the growth of beneficial microorganisms, and by making changes in the physiological characteristics, it increases the resistance of the plant against the stress of heavy elements.
Drought stress
Fatemeh Aghaei; Raouf Seyed Sharifi; Salim Farzaneh
Abstract
IntroductionWater limitation is one of the most important abiotic factors that can limit plant growth and yield due to production of reactive oxygen species (ROS) like H2O2 and the reduction of chlorophyll content. To protect against oxidative stress, plant cells produce both antioxidant enzymes such ...
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IntroductionWater limitation is one of the most important abiotic factors that can limit plant growth and yield due to production of reactive oxygen species (ROS) like H2O2 and the reduction of chlorophyll content. To protect against oxidative stress, plant cells produce both antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT) and peroxidase (POX), and non-enzymatic antioxidants such as low weight molecules like proline, sugars and ascorbate. Also water limitation disturbs the mineral-nutrient relations in plants through their effects on nutrient availability and numerous of physiological and biochemical destruction in the vegetative and reproductive periods of plant development. Several strategies have been suggested in order to improve yield under abiotic and biotic stresses in plants, among them application of Plant Growth Promoting Rhizobacteria (PGPR) and nano particles such as nano iron-silicon oxide play a key role in yield improvement. A better understanding of physiological responses under water limitation may help in programs which the objective is to improve the drouht resistance of crop. During the course of these stresses, active solute accumulation of compatible solutes such as proline and the activities CAT, POD and PPO enzymes are claimed to be an effective stress tolerance mechanism. Therefore, the aim of this study was to evaluate the effects of bio-fertilizers and nano iron oxide and nano oxide on some physiological and biochemical (i.e., antioxidant enzyme activity, chlorophyll, protein, soluble sugars and proline) responses of triticale under water limitation conditions.Materials and methodsAn experiment was conducted as factorial based on randomized complete block design with three replicates at the research farm of faculty of Agriculture and Natural Resources, University of Mohaghegh Ardabili in 2021. The experimental factors were included of irrigation in three levels (full irrigation as control, irrigation withholding at 50% of booting and heading stages as severe and moderate water limitation respectively (BBCH 43 and 55 respectively), application of bio fertilizers in four levels (no application as control, application of Azospirilum, Pseudomonas, both application Azospirilum and Pseudomonas) and nanoparticles foliar application at four levels (foliar application with water as control, nano iron oxide foliar application (1 g.L-1), nano silicon oxide (50 mg.L-1), both application nano iron-silicon oxide). Psedomunas and Azospirilum were isolated from the rhizospheres of wheat by Research Institute of Soil and Water, Tehran, Iran. For inoculation seeds were coated with gum Arabic as an adhesive and rolled into the suspension of bacteria until uniformly coated. The strains and cell densities of microorganisms used as PGPR in this experiment were 1×108 colony forming units (CFU). In each plot there were 5 rows with 2 m long. In each experimental plot, two marginal rows and 0.5 m from beginning and ending of planting lines were removed data were measured from the middle lines. The used nano silicon-iron oxide had the average particle size less than 30 nm and special surface of particles was more than 30 m2.g-1. They were product of Nanomaterial US Research which was provided by Pishgaman Nanomaterials Company of Iran. Nano iron oxide and nano silicon powder added to deionized water and was placed on ultra sonic equipment (100 W and 40 kHz) on a shaker for better solution. Foliar application of nano silicon oxide and putrecine were done in two stages of period growth BBCH 21 and 30.Results and discussionThe results showed that total chlorophyll content (48.16%), quantum yield (36.05%), relative water content (35.83%) and grain yield (43.28%) increased in dual application of bio fertilizers and nano particles foliar application under full irrigation conditions compared to no application of bio fertilizers and nano particles under irrigation cut off at booting stage. But under such conditions, electrical conductivity, hydrogen peroxide and malondialdehyde content decreased 35.67, 53.16 and 56.32% respectively compared to no application of PGPR and nanoparticles under irrigation withholding in booting stage. Also, the application of PGPR and nanoparticles under irrigation cut off in booting stage increased the activity of catalase, peroxidase and polyphenol oxidase enzymes (47.06, 55.69 and 36.53% respectively), proline and soluble sugars content (45.41 and 46.93% respectively) compared to no application of PGPR and nanoparticles under full irrigation conditions.ConclusionBased on the results of this study, the application of plant growth promoting rhizobacteria and nonoparticle can increase grain yield of triticale under water limitation conditions due to improving biochemical and physiological traits.
Heavy metals
Hadis Kakaei; AliAshraf Amirinejad; Mokhtar Ghobadi
Abstract
IntroductionHeavy metals are non-biodegradable and persistent in nature thereby disrupting the environment and causing huge health threats to humans. Cadmium (Cd) is a toxic heavy metal that enters the environment through various anthropogenic sources, and inhibits plant growth and development. Cadmium ...
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IntroductionHeavy metals are non-biodegradable and persistent in nature thereby disrupting the environment and causing huge health threats to humans. Cadmium (Cd) is a toxic heavy metal that enters the environment through various anthropogenic sources, and inhibits plant growth and development. Cadmium toxicity may result from disturbance in plant metabolism as a consequence of disturbance in the uptake and translocation of mineral nutrients. The use of plant hormones has been introduced as a simple and suitable strategy to reduce the effect of heavy metals in plants. A new method for reducing the effect of cadmium on plants is the use of growth regulators such as salicylic acid (SA). Tomato (Lycopersicon esculentum) is an important vegetable that is rich in minerals, various vitamins and antioxidant compounds. Since the cultivation of tomatoe, as an important and highly productive crop, is very common in many parts of Iran, there is a possibility of contamination of the soil under cultivation with cadmium. Therefore, the present study was conducted to evaluate the the effects of foliar spraying of salicylic acid on reducing Cd-induced stress in tomato (Lycopersicon esculentum L.).Materials and methodsA factorial experiment based on a complete randomized design with three replications was conducted in a greenhouse of Razi University. Factors included Cd at three levels (0, 15 and 30 mg kg-1 as Cd(NO3)2) and SA at three levels (0, 250, and 500 μM). The solutions containing Cd-(NO3)2 were sprayed uniformly on the sub-samples separated from the original soil sample according to the desired concentrations. The samples were kept moist for 30 days at moisture conditions close to field capacity. At the four-leaf stage, SA solutions were sprayed three times on the foliage of the plants, until the beginning of flowering. After harvesting, some characteristics including soluble sugars and proline contents, plant height, dry weights of shoots and roots, and root volume and length were determined. All plant parameters were then averaged for each pot. Also, Cd concentrations in extracts obtained from the digestion of leaf tissues, were measured by Varian AA220 atomic absorption spectrophotometer. The analysis of variance (ANOVA) and comparison of means (Duncan's multiple range test) were performed using SPSS-16 software.Results and discussionThe results revealed that Cd stress reduced all plant characteristics, such as plant height, root volume and root length, as well as, dry weights of shoots and roots, and elevated leaf Cd concentration, proline content and soluble sugars in tomato. However, the SA application resulted in improvements in growth parameters. Also, the results showed that the interaction effects of Cd and SA on the most growth characteristics such as plant length, shoot and root dry weights, stem diameter, leaf area, and proline content, soluble sugars and Cd concentration were significant (P <0.01). The highest amount of soluble sugars (0.48 mg kg-1), proline content (26.3 mmol g-1) and Cd concentration (0.685 mg) were obtained in 30 mg kg-1 of Cd and 0 μM SA. Also, the highest amount of soluble sugars (0.53 mg kg-1), plant length (44.6 cm), root length (19.6 cm), shoot dry weight (7.51 g), and leaf area (268.2 cm2) were found in the treatment of 500 μM SA and 0 mg kg-1 Cd.ConclusionThe application of salicylic acid effectively increased the all measured growth parameters, including plant biomass, and total root volume. Cd stress reduced growth indices and, increased proline content and soluble sugars in tomato. Also, it seems that under Cd-induced stress, SA is an effective approach for improving crop growth by increasing plant resistance. In general, the application of appropriate concentration of salicylic acid (500 μM), as a plant hormone, is an effective, simple and low-cost strategy to reduce the adverse effects of Cd (30 mg kg-1 soil) stress in tomato.
Heavy metals
Raheleh Rahbarian; Elham Azizi; Asieh Behdad; Atena Mirblook
Abstract
IntroductionDracocephalum moldavica L. is a herbaceous, annual plant from the Lamiaceae family that is native to Central Asia and domesticated in Central and Eastern Europe. Essential oil of this plant has antimicrobial and bacterial properties and has many uses in the pharmaceutical, cosmetic, food ...
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IntroductionDracocephalum moldavica L. is a herbaceous, annual plant from the Lamiaceae family that is native to Central Asia and domesticated in Central and Eastern Europe. Essential oil of this plant has antimicrobial and bacterial properties and has many uses in the pharmaceutical, cosmetic, food and perfumery industries. Lead stress in plants causes disturbances in mitosis, leaf chlorosis, decreasing of the vegetative and productive growth stages and reduces photosynthesis and enzyme activities. One of the effects of lead toxicity is due to the similarity of the structure of calcium ions and lead, and for this reason, lead ions disrupt many mechanisms related to calcium ions and prevent the activity of key enzymes.Photosynthesis is one of the most sensitive metabolic processes to lead toxicity, and several studies have reported the inhibition of photosynthesis under lead stress in various plants. Lead prevents the absorption of elements such as magnesium and iron. These elements play a role in the structure of chlorophyll and the oxygen-releasing complex in photosystem II. Heavy metals such as lead inhibit chlorophyll biosynthesis by inhibiting the enzymes gamma-aminolevalonic acid dehydrogenase and protochlorophyll reductase. Also the availability of different nutrients in the soil changes significantly under the influence of environmental stress so that using of vermicompost can be useful in stress condition as well as Jasmonate. Jasmonate is the final oxidation product of unsaturated fatty acids such as linolenic acid, that is effective in increasing the activity of plant defense systems under environmental stress conditions such as lead stress. In order to study the effect of pb (0, 100, 200, 300, 400 mg kg-1 soil) and jasmonate (0, 50, 100, 150 mmol l-1) on Dracocephalum moldavica L. under controlled conditions in soil enriched with vermicompost and without vermicompost an experiment designed and it was done under greenhouse conditions.Materials and methodsThis test was done in a random factorial design with 4 repeats and indices including CO2 assimilation rate, transpiration rate, stomatal conductance, water use efficiency(WUE), PSɪɪ photochemical efficiency (Fv/Fm), photosynthesis quantum performance, electron transfer rate (ETR), were measured in vegetative and reproductive growth stages.Results and discussionIn the conducted study, it was found that CO2 assimilation rate, water use efficienty, stomatal conductance and Fv/Fm were significantly decreased as lead concentration was increased. Also jasmonate treatment significantly increased CO2 assimilation rate, water use efficienty, stomatal conductance and Fv/Fm in lead stress condition. So that plant treated with 400 mg kg-1 soil pb and 0 mmol l-1 jasmonate showed the lowest CO2 assimilation rate, water use efficienty, stomatal conductance and Fv/Fm while plant treated with 0 mg kg-1 soil pb and 150 mmol l-1 jasmonate showed the highest CO2 assimilation rate, water use efficienty, stomatal conductance and Fv/Fm. transpiration rate was significantly increased as well as increasing pb concentration so that plant treated with 400 mg kg-1 soil pb showed the highest transpiration rate. Also jasmonate treatment significantly decreased transpiration rate in lead stress condition. Vermicompost increased CO2 assimilation rate, water use efficienty, electron transfer rate (ETR) and significantly decreased transpiration rate in lead stress condition.Jasmonate reduces the destructive effects caused by stress on photosynthetic indicators such as the amount of chlorophyll and carotenoids and also increases the performance of photosystem II and consequently increases plant photosynthesis under stress conditions. It has been reported that methyl jasmonate can maintain the concentration of chlorophyll in the reaction center, thereby improving the speed of electron transfer and increasing the efficiency of photosystem II. In addition, jasmonate can prevent the severe reduction of stomatal conductance under stress conditions and increase the quantum efficiency of photosynthesis.In the response of plants to stress, jasmonates act as genes encoding inhibitory proteins such as theonine, hydroxyproline and proline, and in general, by activating defense mechanisms, they help the plant in reducing the absorption and accumulation of heavy metals. Organic fertilizers can also improve plant performance under environmental stress conditions. Vermicompost fertilizer increases porosity, increases absorption and retention of nutrients, improves ventilation, drainage and microbial activity in the soil.ConclusionHaving nutritious mineral elements and plant growth hormones can improve plant growth in the presence of environmental pollutants such as heavy metals by influencing the physiological characteristics. It can be said based on the results obtained lead stress decreased photosynthesis index through effect on electron transport chain and photosynthetic pigments while jasmonate treatment and Soil enriched with vermicompost can reduce the destructive effects of lead stress. So that using of jasmonate and vermicompost in lead stress condition Recommended.
Breeding plants for stress conditions
Fatemeh Saber; Rasool Asghari Zakaria; Nasser Zare; Salim Farzaneh
Abstract
IntroductionDurum wheat (Triticum turgidum L. var. durum) is the second most crucial wheat and the tenth main crop globally. Salinity stress prevents water absorption from the soil and disturbs the ionic balance of the cell. As a result, metabolic processes such as seed germination, seedling growth, ...
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IntroductionDurum wheat (Triticum turgidum L. var. durum) is the second most crucial wheat and the tenth main crop globally. Salinity stress prevents water absorption from the soil and disturbs the ionic balance of the cell. As a result, metabolic processes such as seed germination, seedling growth, flowering, and seed formation are inhibited. The purpose of this study is to the evaluation of the effects of salinity stress on the germination and seedling growth of different durum wheat genotypes, as well as to identify and select tolerant genotypes using multivariate selection indices such as the ideal genotype selection index (IGSI) and the multi-trait genotype–ideotype distance index (MGIDI).Materials and methodsIn this research, 50 different durum wheat lines and genotypes were prepared by the Agricultural Research, Education and Extension Organization of Iran and were evaluated in terms of tolerance to salinity in the germination stage, as a factorial experiment, based on a completely randomized design with three replications. Salinity levels included 0, 75, 150, and 300 mM sodium chloride concentrations. After one day, counting the number of germinated seeds was started daily. Based on the data obtained from counting the germinated seeds, various parameters of seed germination, including coefficient of the velocity of germination (CVG), germination index (GI), average germination duration (MGT), average daily germination (MDG) and final germination percentage (FGP) were calculated. In addition, after ten days, the characteristics such as root and shoot length and dry weight of root and shoot were measured for each genotype. Also, using the seedling height and dry weight, and the seed germination percentage, the seedling vigor was calculated. The MGIDI index of the studied genotypes was calculated based on factor scores of the first three factors with eigenvalues greater than one in factor analysis based on principal component analysis (PCA). The IGSI index also was calculated considering all the traits.Results and discussionThe analysis of variance showed significant differences (p < 0.01) between salinity levels and between genotypes in terms of all traits. But, the interaction effect of salinity × genotype was not significant for all studied traits. The comparison of the salinity levels showed that the germination components and the length and weight of the root and shoot decreased by increasing salinity levels. Factor analysis based on principal component analysis (PCA) showed that in normal conditions and salinity (150 mM NaCl) stress conditions, the first three factors with eigenvalues greater than one explained 83.89 and 84.97 percent of the total variance among the traits, respectively. According to the MGIDI index, under normal conditions based on the selection intensity of 30%, genotypes G30, G39, G51, G19, G14, G2, G31, G34, G5, G48, G7, G26, G1, G23, and G33 have the lowest values and were favorable. In 150 mM salinity condition, genotypes G9, G2, G29, G5, G12, G47, G30, G1, G31, G10, G34, G41, G13, G49, and G16 were the best genotypes with the lowest MGIDI values. According to the IGSI index in the 150 mM salinity level, genotypes G5, G29, G2, G30, G23, G9, G12, G1, G10, G41, G47, G34, G48, G16, and G13 have the highest values (between 0.60 to 0.80) were considered as desirable genotypes. On the contrary, genotypes G43, G46, G4, G26, G15, G19, G8, G14, G35, G44, G24, and G42, having IGSI values less than 0.40, were considered weak genotypes in this condition.ConclusionIn this study, IGSI and MGIDI indices were used to evaluate the response of different durum wheat genotypes to salinity using all studied traits. In general, the results of the present research showed a considerable genetic diversity among the studied durum wheat genotypes in terms of salinity tolerance at the germination stage, which can be used in the breeding programs of this valuable crop. Also, the IGSI and the MGIDI indices were effective in identifying superior genotypes based on all the studied traits. Using these indices in breeding programs to select desirable genotypes can be fruitful and effective.
Drought stress
Rezvanea Tavosi; Mohammad Sayyari; ALi Azizi
Abstract
IntroductionE. purpurea is a plant that blooms in North America during the summer. It is essential for the pharmaceutical industry because it boosts the immune system and can be used for various external and internal ailments. Abiotic stresses like drought are significant problems for plant productivity. ...
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IntroductionE. purpurea is a plant that blooms in North America during the summer. It is essential for the pharmaceutical industry because it boosts the immune system and can be used for various external and internal ailments. Abiotic stresses like drought are significant problems for plant productivity. Many studies have been done on how these stresses affect agricultural plants because they cause economic losses. Drought affects plant growth and development by reducing crop growth rate, biomass accumulation, cell division and expansion, leaf size, stem elongation, root proliferation, and stomata oscillations. Although the effect of drought stress on various characteristics of coneflower has been studied in many research, few researchers have investigated the changes in the essential oil content of this important medicinal plant under drought stress. Due to a water shortage in Iran and the growing use of herbal medicines, studying how drought stress affects the composition of coneflower essential oil is crucial.Materials and methodsThis research was carried out in 2021 in the greenhouse of the Department of Horticultural Sciences, Faculty of Agriculture, Bu-Ali Sina University, Hamedan, Iran. The study was done as a factorial based on a completely random design with two factors of drought stress (80, 60, and 40% FC) and growth stage (10 leaves, pre-flowering, and flowering stage) in three replications. Took coneflower seeds were planted in cultivation trays. After 60 days, the seeds germinated, and the seedlings were prepared and transferred to pots. The weight method was used to determine soil moisture content. The pots were weighed daily and watered to maintain the intended level of irrigation. After the drought stress period ended, the plants with their roots were transferred to the lab, and some growth, biochemical, and phytochemical characteristics were measured.Results and discussionThe results of the analysis of variance showed that the interaction effect of irrigation levels and phenological stages was significant for the characteristics of leaf area, stem length, flower diameter, flower dry weight, chlorophyll a, chlorophyll b, carotenoid and total phenol and flavonoid of the flower and root. The results showed that drought stress caused a significant decrease in the growth characteristics, chlorophyll a, carotenoid, and increased chlorophyll b content of coneflower in different stages of growth. The concentration of coneflower's total phenol and flavonoid under severe drought stress increased by 37.58 and 25.67, respectively. Also, the antioxidant capacity of the coneflower flower increased under severe drought stress, but drought stress did not affect the antioxidant capacity of the roots. In addition, the results showed that more than 70% of the essential oil components at the time of applying the control in the 10-leaf and pre-flowering stage, and severe stress in all three stages of growth consisted of four compounds: Germacrene D, n-Dodecane, n-Tridecane, and n-Undecane. Compared to the control, most of the essential compounds of coneflower under severe drought stress decreased in the 10-leaf growth stages and pre-flowering but increased in the flowering stage. Severe drought stress caused a decrease in Germacrene D in the 10-leaf and flowering stages (41.6 and 41.3%, respectively) and increased it in the pre-flowering stage (77.2%). During drought conditions, plants reduce the number and area of their leaves as an adaptation strategy and first defense mechanism. Plants exposed to environmental stress can increase their stress tolerance by producing more phenol, flavonoid, and antioxidants. These non-enzymatic antioxidants help reduce the adverse effects of stress on plants. Based on the findings of various research, it can be said that Germacrene D, Spathulenol, β-Caryophyllene, and α-Humulene are the main components of the essential oil of coneflower. In agreement with our results, the research findings showed that severe drought stress (40% FC) caused a significant decrease in the phytochemical compounds of coneflower. Secondary metabolites are influenced not only by genetics but also by changing environmental patterns.ConclusionWith increasing drought stress levels, growth characteristics, chlorophyll a, carotenoid, and root total phenolic content of coneflower decreased significantly. Also, drought stress increased stem diameter, chlorophyll b, total phenol content, total flavonoid, and antioxidant capacity of flowers. Under severe drought stress, four compounds of Germacern D, N-dodecane, N-tridecane, and N-one-decane, which are the dominant components of the root essential oil of this plant in the present study, decreased in the 10-leaf and flowering stages but increased in the pre-flowering stage. In general, it can be concluded from the current research results that applying drought stress can help improve coneflower root essential oil composition.
Heavy metals
Asma Najarzadeh; Hassan Farahbakhsh; Mahdi Naser Alavi; Rohalah Moradi; Mahdi Naghizadeh
Abstract
IntroductionSoil contamination with heavy metals is one of the most important challenges related to the protection of water and soil resources. Heavy metals are metals that have a density of more than 5 grams per cubic centimeter. Among heavy metals, cadmium is of special importance due to its high solubility ...
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IntroductionSoil contamination with heavy metals is one of the most important challenges related to the protection of water and soil resources. Heavy metals are metals that have a density of more than 5 grams per cubic centimeter. Among heavy metals, cadmium is of special importance due to its high solubility in water and quick and easy absorption by the plant root system. This element has been introduced as the fourth dangerous element for vascular plants (Kok et al., 2010). By accumulating in the root environment, cadmium can cause a decrease in growth, respiration, damage to the mechanisms involved in photosynthesis, and inhibit the activity of enzymes and the lack of nitrogen and phosphorus in the plant. Borage (Borago officinalis L.) is a valuable annual medicinal herb suitable for cultivation in many countries, including Iran. Borage (Borago officinalis L.) is considered as a native of both Europe and Asia. Several species around the globe fall under the denomination of “borage”. The presence of the highest γ-linolenic acid content in the seeds of borage makes borage distinctively important mainly for the nutraceutical and pharmaceutical research. γ-Linolenic acid is an omega-6 polyunsaturated fatty acid which cannot be synthesized in the body and hence falls into the category of essential fatty acids (Evesh et al., 2019). The present study was carried out with the aim of investigating the physiologic and biochemical responses of the medicinal plant Borage (Borago officinalis L.) to cadmium stress. Materials and methodsThis experiment was conducted in the form of a completely random design in the greenhouse of Shahid Bahnar University, Bardsir College of Agriculture, Shahid Bahnar University, Kerman, at an average temperature of 25 degrees Celsius during the day and 20 degrees Celsius during the night, with a relative humidity of 60%. First, concentrations of cadmium (0, 1.25, 2.5, 5, 10, 20, 40, 80, 120, 160 mg kg-1) were prepared using cadmium chloride (Merck company) and the soil was uniformly contaminated with cadmium. The contaminated soil was incubated under constant humidity and temperature conditions for 30 days and then poured into pots with a capacity of 3 kg of soil. Plant seeds were disinfected with alcohol and 5% sodium hypochlorite solution and immediately washed several times with distilled water. Five seeds were planted in the pots containing the studied treatments and at a depth of 2 to 3 cm. Two months after planting, when the plant was in the 50% flowering stage, the growth and performance characteristics of the plant including the number of flowers, number of leaves, branch length, root length, shoot weight, root weight, flower weight were measured. Some biochemical characteristics (catalase, ascorbate peroxidase, guaiacyl peroxidase, protein, proline and photosynthetic pigments) were measured. Results and discussionThe studied treatments significantly (p≤0.01) affected the biochemical, physiologic and performance characteristics of European borage. Increasing the concentration of cadmium had an inhibitory effect on the growth parameters of the plant, and this effect was clearly evident in pollution above 80 mg kg-1. Number of flowers, number of leaves, flower weight, root weight, total weight, root length and branch length decreased significantly with increasing cadmium concentration. The flowering of the plant was 71% at the pollution level of 120 mg per kilogram. At this level of pollution, the root weight was reduced by 69.9%. The weight of aerial parts decreased by 59.7% at the pollution level of 160 mg kg-1. The activity of ascorbate peroxidase enzyme increased up to 20 mg kg-1 treatment and after that the activity of ascorbate peroxidase enzyme decreased with the increase of cadmium concentration. Proline concentration increased with increasing cadmium contamination. Photosynthetic pigments also decreased in high concentrations of cadmium. The cause of the adverse effects of cadmium on plants in contaminated soils can be attributed to more absorption of cadmium by the plant and growth disturbance caused by cadmium toxicity in the plant, reduction of growth rate, reduction of water absorption and absorption of other ions affecting the activities plant growth (Veselov et al., 2003), the reduction of cytokinin hormone activity, which has a significant effect on cell proliferation and growth, or the negative effect of cadmium on energy production in mitochondria was attributed (Fotohi et al., 2011). Cadmium causes disturbances in the overall metabolism of cells. (Xie et al., 2021) Cadmium toxicity in plants can lead to negative effects on the photosynthesis process. This action takes place through damage to some photosynthetic enzymes, especially those involved in the Kelvin cycle and chlorophyll biosynthesis (Mishra et al., 2006). ConclusionThe results showed that the yield of European borage was not affected by cadmium up to a concentration of 1.25 mg kg-1. The activity of antioxidant enzymes increased up to the treatment of 20 mg kg-1 and then decreased with increasing cadmium concentration, which indicates oxidative stress. Photosynthetic pigments and chlorophyll fluorescence index decreased with increasing cadmium concentration. Considering the tolerance and resistance of some medicinal plants to the conditions in soils contaminated with heavy metals, it is possible to use the cultivation of some medicinal plants as a solution for the management and exploitation of lands that have medium contamination with heavy metals. Considering the number of flowers, flower durability and high yield, the European borage plant can be a suitable candidate for cultivation in polluted areas, of course, additional studies with the approach of reducing the adverse effects of stress and reducing the concentration of cadmium element in the soil are needed.
