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Effects of Seed Priming Methods on Germination Parameters of Ajowan (Carum copticum) Seed
Somayeh Malekzade, Seyfollah Fallah2,
Volume 1, Issue 2 ((Autumn & Winter) 2015)
Abstract
In order to investigate the effect of priming techniques on germination parameters of ajowan (Carum copticum L.) seed, an experiment was conducted in completely randomized design with four replications. The experiment treatments included a control (no priming), three hydropriming levels with distilled water (24, 36, and 48 h), three osmopriming levels with PEG (solutions with osmotic potential of -4, -8 and -12 bar), three hormone priming levels with GA3 (50, 100 and 150 ppm), three halopriming levels with KNO3 solution (2, 3, and 4%) and three zinc sulfate levels (0.1, 0.2 and 0.3 %). The results showed that priming treatments had a significant effect on all traits. The rate and percentage of germination were declined in some priming treatments compared to control. Radicle length and root dry weight were decreased in polyethylene glycol -8 bar. Polyethylene glycol -4 bar and 24h hydropriming treatments significantly decreased shoot length and allometry coefficient. However, the treatment of 100 ppm hormone priming significantly increased these traits. Hydropriming 24 h treatment significantly increased germination rate, percentage and seed vigor, but hydropriming 48 h significantly increased radicle and shoot length compared to control. In conclusion, according to the priority of germination or radicle, shoot growth and seed priming cost as well, the hydropriming 24 or 48 h can be recommended as most appropriate priming type for ajowan seeds.

Investigation of Electrical Conductivity and Seedling Growth of Red Bean (Phaseolus vulgaris) Seed Grown under Drought Stress and Foliar Application of Zinc and Manganese
Mehdi Baraani-Dastjerdi, Mohammad Rafieiolhossaini, Abdorazagh Danesh-Shahraki,
Volume 1, Issue 2 ((Autumn & Winter) 2015)
Abstract
In order to evaluate the electrical conductivity and seedling growth characteristics of red bean seed grown under drought stress and foliar application of zinc and manganese, a split factorial experiment was conducted in a Randomized Complete Block Design in the field and also laboratory experiment at Shahrekord University in 2011. Factors included three levels of drought stress (irrigation after 50, 70 and 90 mm evaporation from class A pan) as the main plot and three levels of zinc foliar application (with water, 100 and 200 grams per hectare zinc), and three levels of manganese foliar application (with water, 150 and 300 grams per hectare manganese) in a factorial combination as subplot. The results showed that severe drought stress led to decrease of electrical conductivity while the seedling and root length of red bean seed were increased. In the measured characteristics, Mn foliar application had a significant effect on electrical conductivity and root dry weight. In different Mn foliar application treatments, the lowest electrical conductivity was related to control while the maximum seedling dry weight was observed at 150 g Mn foliar application per hectare. Zn foliar application had a significant effect on all the traits measured during this experiment. Based on means comparison, the highest seedling dry weight, shoot, seedling and root length, as well as the lowest electrical conductivity, belonged to the 100 g Zn foliar application per hectare. The highest root dry weight was obtained for 200 g Zn per hectare which no significant difference was observed with 100 g Zn per hectare. According to the results of this experiment, mild stress and foliar application of zinc and manganese led to increasing the quality of the produced seeds. In total, foliar application of zinc and manganese (at the amount of 100 and 300 g ha-1 respectively) with mild stress (irrigation after 70 mm evaporation from class A pan) are recommended for the production of seeds with high vigor under this region conditions.

Germination Model for Arizona Cypress (Cupressus arizonica) in Response to Temperature and Drought Stress
Fatemeh Aliyari, Ali Soltani, Mehrdad Zarafshar,
Volume 2, Issue 2 ((Autumn & Winter) 2016)
Abstract

Select the appropriate tree species and compatible with harsh environmental conditions, with a high survival rate and optimal growth, is very important in the principled forestation projects. Offering moisture - temperature - time seed germination model is one of the solutions to the prediction of seed germination patterns as in this study, germination behavior model in four replications of 50 seeds of Cupressus arizonica (dishes 11cm) on the incubator was examined by applying five levels of water stress (0, -0.5, -1, -1.5, -2 MPa) and temperature treatments (10, 15, 20, 25, 30 °C). The results showed that the optimum temperature (To) and the basic temperature (Tb) for germination is 19.23±0.5 and 6.54 ± 0.0 °C respectively, and amount of the hydro time constant (θH) for this species is 0.29±0.11. According to the results, temperature and water potential factors and their interaction affected significantly on time and percent germination. Value of the hydrothermal time model was determined by using θHT= [(Ψ-Ψb (g)) (T-Tb)] tough model that its rate was 126.3 MPa°C. d with 0.87 coefficients of determination.


Effect of Titanium Dioxide Nanoparticles and Carbon Nanotube on Seed Germination Characteristics of Some Hordeum vulgare Hulled Varieties
Mahmod Reza Tadayon, Mohammad Rahimi,
Volume 3, Issue 2 ((Autumn & Winter) 2017)
Abstract

The purpose of this study was to evaluate the effect of Nano TiO2 and Nano CNT on some germination indices and growth parameters of some hulled barley cultivars. The experiment was conducted in a laboratory at Shahrekord University during 2014. The study was a factorial, adopting a completely randomized design with four replications. Treatments consisted of titanium dioxide nanoparticles and carbon nanotube (CNT) in four concentrations (0, 10, 30 and 60 mg.l-1) which were applied to seeds of hulled barley cultivars such as Bahman, Makoii and Nosrat. The traits measured were the dry weight of seedling and seedling length, germination percentage, germination rate, mean germination time, the percentage of resistance of radical, seedling vigor length and weight index. The results showed that carbon nanotubes treatments with 60 mg.l-1 had a significant impact on germination percentage, germination rate, seedling vigor length and weight index and seedling dry weight, as compared with other treatments. In this experiment, the highest percentages of resistance of radicle, seedling vigor weight index and seedling dry weight of Nosrat Cultivar were obtained under 60 mg.l-1 carbon nanotube treatment, which was 70, 122.2 and 64.9%, respectively, as compared with control treatment. In addition, 60 mg.l-1 carbon nanotube treatment increased the seedling vigor of Makoii cultivar by 39.8%, as compared with the control treatment. The findings were that in terms of seedling vigor length and weight index, seedling length, seedling dry weight and the percentage of resistance of radical, the Nosrat Cultivar showed better morphological characteristics than Bahman and Makoii cultivars, under laboratory conditions.
 


Effect of Magnetic Field on Seed Germination of Guizotia abyssinica under Drought Stress Conditions
Samaneh Hosseini, Mohammad Rafieolhossaini, Parto Roshandel,
Volume 5, Issue 1 ((Spring and Summer) 2018)
Abstract
Extended abstract
Introduction: Niger with the scientific name of Guizotia abyssinica (L.F.) Cass. belongs to the Asteraceae family. Niger seed contains 50-75 percentage of oil which is used in the treatment of rheumatism and burns, and as a substitute for olive oil. Its meal is also used for animal feeding. Environmental crises sustained by living systems are considered as stress. Drought stress is one of the non-biological stresses. Yield reduction due to this type of stress is reported to be higher than that related to other stresses. Since plant development starts from germination and for survival, the seeds should germinate to adapt themselves to the environmental conditions and establish themselves in the soil, the success of passing the germination stage will play an important role in other stages of plant establishment. Different studies have shown the positive effect of magnetic field on increasing germination characteristics. In this regard, applying a magnetic field before planting is a safe and inexpensive method for increasing germination and seedling growth. Seed priming is useful for a faster and more powerful response to drought stress and among different types of priming, physical priming is of particular importance for ecological reasons and for not having a negative impact on the environment.
Materials and Methods: In order to study the effect of seed physical pre-treatment and drought stress on seed germination characteristics of Niger, an experiment was conducted as factorial in a completely randomized design with three replications at the Research Laboratory of Seed Science and Technology at Shahrekord University. Different magnetic field intensities at five levels including (0, 50, 100, 150 and 200 mT (at 5 minutes period)) as the first factor and drought stress at five levels (0, -4, -5, -6 and -7 bar Polyethylene Glycol6000) as the second factor were considered.
Results: The results of variance analysis showed that the effect of drought stress, magnetic field intensity and their interaction were significant on all of the evaluated characteristics. The maximum germination percentage and rate and the minimum of T10 and T50 were observed in 50 mT field intensity under normal conditions. The minimum germination index under normal conditions and the maximum length and shoot dry weight under non-treatment conditions and the maximum root and shoot fresh weight in 200 mT field intensity under normal conditions were obtained. The maximum root length and dry weight were observed in 50 and 100 mT field intensity under normal conditions, respectively. 
Conclusions: Seeds which cross through a magnetic field, become swollen and probably as a result, the activity of auxin hormone in these seeds increases. In addition, the respiration level also increases in them and they have higher levels of energy and activity, which results in faster and more uniform germination and the creation of stress-resistant plants. In this study, although by increasing drought stress intensity, negative effects were observed on germination characteristics, the magnetic field under these conditions improved some germination characteristics. In general, for the purpose of improving germination and alleviating drought stress conditions, for 0, -5 and -7 bar potentials, the field intensity of 50 mT and for -4 and -6 bar potentials, the field intensity of 150 mT are recommended.
 
Highlights:
  1. The effect of magnetic field on germination of multipurpose seed of Niger plant.
  2. The effect of drought stress on germination of multipurpose seed of Niger plant, given Iran’s being located in dry belt.
  3. The positive effect of magnetic field on germination of Niger seed to improve the negative effects of drought stress.

Effects of Seed Pretreatments on Seed Germination Characteristics of Sugar Beet (Beta vulgaris) under Drought Stress Conditions
Jamal Kiani, Ali Abbasi Surki, Abdulrazagh Danesh Shahraki,
Volume 5, Issue 1 ((Spring and Summer) 2018)
Abstract
Extended abstract
Introduction: Drought stress is one of the major problems in sugar beet production in Iran, and is the most important limiting factor for germination and establishment of sugar beet in the early stages of growth. Seed priming with chemical, nutrient elements or pre-chilling techniques are the most effective methods to improve germination percentage and speed, leading to uniform and tolerant seedlings in adverse environmental conditions.
Material and Methods:  In order to assess the effect of cold stratification and HCl treatments on the germination of sugar beet seed, cv. Ekbatan, under drought stress conditions, a RCBD factorial experiment with three replications was conducted in Seed Science and Technology Lab of Shahrekord University.  The first factor was stratification in two levels; the second factor was  seven levels of pretreatments including 2, 4 and 6 hours’ soaking in water and 0.03 HCL accompanied with control, and the third factor was four drought levels (control, -2, -4, -6 bar).
Result: Compared with the control, seed germination percentage and germination rate increased by at least 5-fold, relative germination by 50% and root and shoot length by 10%, due to stratification and duration of exposure to HCl treatments. With no stratification, germination traits increased with increases in exposure time in acid, and the highest values were obtained for the seeds exposed to HCl 0.03 normal for 6 hours. Although under optimal conditions, the effect of HCl was compensated for by stratification, in drought conditions, the highest values ​​were observed in stratified seeds and those placed in acid.
Conclusions: Since successful establishment of sugar beet seedlings at drought stress conditions is critical to achieving optimum density and yield, application of stratification treatments for one week and seed exposure to HCl increased the seed performance under stress conditions. This trend continued to increase with drought stress intensity, and placement of seeds in acid doubled seed germination in -2 bar drought conditions, which continued by 4 times in -6 bar, compared with stratified control seeds. Compared to separate application of the treatments, application of stratification and HCl treatments had synergistic effects on sugar beet seed performance, especially under drought stress conditions.
 
 
Highlights:
  1. Cold stratification and hydrochloric acid treatments increase the efficiency of sugar beet seeds under drought stress conditions.
  2. Cold stratification and Hydrochloric acid treatment have a synergistic effect on sugar beet seeds.


Investigation of Seed Germination Indices and Anthocyanin Content of Niger (Guizotia abyssinica) Seedling under the Effect of Three Nanoparticles
Moazzameh Eskandarinasab, Mohammad Rafieiolhossaini, Parto Roshandel, Mahmoud Reza Tadayon,
Volume 5, Issue 2 ((Autumn & Winter) 2019)
Abstract


Extended abstract
Introduction: The use of nanotechnology as a diverse and applied discipline is ongoing in almost all areas of science. Fertilizers and nano-nutrients have the effective properties which help the production of plants depending on their needs to regulate the plant growth. Plants under stress conditions are willing to produce natural nanoparticles to continue their growth. Nano TiO2 has a high photocatalytic effect and as a catalyst, it is mainly used in water, electronic devices, conversion and storage equipment of Energy as suspension. Sources of SiO2 are very diverse, including natural nanoparticles, anthropogenic particles and engineering nanoparticles. Although, silicon in many crops is not an essential element for growth, it has beneficial effects on plants growth and development. Today, carbon nanotubes are one of the most important materials in industrial programs. These materials, with different methods and specific properties, can play an important role in the production of composite materials, application in medicine, electronic and energy storage. The Niger plant, with the scientific name of Goizotia abyssinica (L.F) Cass, belongs to the Asteraceae family. Its seed, are used in pharmacy, food industry, green manure and for feeding birds and cows. Therefore, the purpose of this experiment was to investigate the effect of type and concentration of three nanoparticles on some of germination characteristics and anthocyanins content in Niger medicinal-oily plant.
 Materials and Methods: In order to evaluate the effect of three nanoparticles on seed germination of Niger, an experiment was conducted as factorial in a completely randomized design with four replications. The treatments of TiO2, SiO2, and CNT were as the first factor while their concentrations in four levels (zero, 10, 30 and 60 mg/l) were as the second factor. In this study the traits of germination percentage, germination rate and mean of daily germination, germination and vigour index, length, fresh and dry weight of radicle and plumule, anthocyanin content and radicle resistance percentage were measured. 
 Results: The germination percentage, germination rate and mean of daily germination decreased by increasing of nanoparticles concentration. The favorable effect of TiO2 on germination index at the concentration of 30 mg/l and radicle dry weight at the concentration of 10 mg/l, was gained compared to control. The positive effect SiO2 on germination index and radicle dry weight at the concentrations of 10 and 60 mg/l, the anthocyanin content and the fresh and dry weight of plumule at the concentration of 60 mg/l was obtained compared to control. Also, the appropriate effect of CNT on germination index at the concentration of 10 and 30 mg/l, the anthocyanin content and radicle dry weight at the concentration of 60 mg/l and plumule fresh weight at the concentration of 30 mg/l, was observed.
Conclusions: According to the results of this study, it seems that the effect of nanoparticles in plants, in addition to the plant, species, type and concentration of nanoparticles, varies depending on the growth stage and physiology of the plant. It seems that nanoparticles at some concentrations can increase the water absorption of seeds and increase seedling growth with their positive effects. Anthocyanins are produced by exposure to stress due to their antioxidant activity. In general, it can be stated that increasing the concentration of nanoparticles caused and increased the oxidative stress in plant. Therefore, it is recommended by investigating the bad effects of nanoparticles on plants, if necessary, use nanoparticles at low concentrations (less than 60 mg/l) to increase the plant's efficiency.
 
Highlights:
  1. The effect of nanoparticles kind and concentration on seed germination indices and anthocyanin content of Niger seedling.
  2. Investigating the interaction of nanoparticle type and concentration as the physical priming factor of seeds on seed germination of multi-purpose Niger plant.

Effect of Stratification and Its Combination with Gibberellic Acid on Seed Dormancy Breaking of Echinophora platyloba
Ali Abbasi Sourki, Zahra Hosseni, Sina Fallah,
Volume 5, Issue 2 ((Autumn & Winter) 2019)
Abstract



Extended Abstract
Introduction: Seeds are a good option for propagation and protection of medicinal plants. Although Seed dormancy is an adaptive strategy for wild medicinal plants, but it is considered as an undesirable trait in domestication and cultivation of them, need to be solved. Echinophora platyloba seed has dormancy despite its remarkable medicinal properties.
Materials and Methods: In order to break seed dormancy, three separate experiment including stratification, hormonal treatment and combination of both were performed. For stratification 10 samples of were placed in a wet bed at 5 ° C for 2, 4, 6, 8, 10, 12, 14 and 16 Week and were compared using a completely randomized design with three replications. For hormonal treatment, the seeds were placed in GA concentrations of 0, 500 and 1000 ppm for 24 hours and then transferred to germination conditions. However, since the breaking of dormancy did not occur, this experiment was not discussed any more. For combined application of hormone and stratification, seeds were placed at mentioned concentrations of gibberellin for 24 hours at 20 ° C and then gibberellin solutions were removed and the seed transmitted to 5 ° C and compared for 2, 4, 6, 8 weeks with a CRD factorial experiment with three replications. The first factor was concentration of gibberellin in three levels and the second factor was the duration of stratification in 4 levels.
Results: Stratification had a positive effect on seed dormancy breaking and 16 week chilling lead to highest germination percentage and rate and vigor indices. The combined application of hormonal treatments accelerated dormancy release and improved seed germination characteristics, which peaked at 8 weeks. 8-week stratification treatment at 5 ° C with 1000 ppm gibberellic acid was the best treatment to overcoming of dormancy in Echinophora-platyloba seeds.
Conclusion: It seems that seed dormancy of Echinophora seeds is physiological, which broke down by moist chilling and simultaneous application of stratification and gibberellin successfully. Although Gibberellin had no effect on dormancy break, it reduced the need for stratification. Combined application of them showed synergistic effects on dormancy release.
 
 
Highlights:

  1. Echinophora seed’s dormancy was broken under stratification conditions, but GA had no effect on it lonely.
  2. The application of gibberellin reduced the chilling demands of Echinophora seeds and the combined application of them had a synergistic effect on dormancy break

Effect of Gibberellin and Salicylic Acid on Tolerance of Pumpkin (Cucurbita pepo) Seedling
Maryam Mokhtari, Sina Fallah,
Volume 6, Issue 1 ((Spring and Summer) 2019)
Abstract


Extended Abstract
Introduction: In order to take more advantage of the spring growing season, the mechanisms of germination of spring plants are of great importance at temperatures lower than the optimum temperature. Since one of the ways to reduce damage due to low temperature is enhancing the seedling antioxidant system, in this study the effects of salicylic acid and gibberellin on germination and antioxidant system of pumpkin (Cucurbita pepo) seeds were investigated under low temperatures.
Materials and Methods: A factorial experiment including four concentrations of gibberellin (0, 250, 350 and 450 mg/L), four concentrations of salicylic acid (0, 0.5, 1 and 1.5 mM) and three temperature levels (8, 11 and 14 °C) was performed with a completely randomized design within controlled conditions and six replications at Shahrekord University in 2017. The seeds were immersed in containers containing solutions of 0, 250, 350 and 450 mg/L of gibberellin and solutions with 0, 0.5, 1, and 1.5 mM salicylic acid, were placed in a growth chamber for 24 h under dark conditions at 15 °C. Then the seeds were washed at the desired temperatures, and the germination was recorded every 24 hours based on the 2 mm of radicle length. At the end of the eighth day, after the separation of normal and abnormal seedlings, 20 normal seedlings were selected from each petri dish. Following that, the germination rate, germination percentage, soluble protein, malondialdehyde, superoxide dismutase, guiacol peroxide enzyme, and catalase enzyme were measured. Comparison of means was conducted by the least significant difference test at the 0.05 probability level.
Results: The results showed that none of the treatments used at 8 °C helped germination of the plant and, therefore, 8 °C treatment was removed from the experiment. At the temperature of 11 ° C, the use of salicylic acid 1 mM and at 14 °C, the use of gibberellin 350 mg/L showed the maximum germination rate and germination percentage, compared with the control. At 11 °C, the activity of antioxidant enzymes was more affected by gibberellin hormone so that the highest activity of superoxide dismutase enzyme was observed in 350 mg/L and the highest activity of catalase and guaiacol peroxidase enzymes and the lowest amount of soluble protein were observed in gibberellin 250 mg/L. The salicylic acid hormone was more successful at 14 ° C. The salicylic acid 1.5 mM increased the activity of superoxide dismutase enzyme; and salicylic acid 0.5 mM increased the activity of catalase and salicylic acid 1 mM improved the activity of guiacol peroxidase. This hormone also succeeded in reducing the amount of soluble protein.
Conclusion: In this experiment, seedling tolerance at low temperatures was confirmed by gibberellin and salicylic acid treatments. It is generally concluded that the use of gibberellin and salicylic acid increases the activity of antioxidant enzymes and, as a result, makes pumpkin (Cucurbita pepo) seedlings tolerant to low-temperature stress, and thus, can ameliorate the effect of possible chilling on growth of this crop at the beginning of the season.
 
Highlights:
  1. Gibberellin and salicylic acid treatments make pumpkin seedling tolerant to low temperatures.
  2. Application of gibberellin and salicylic acid increases the activity of antioxidant enzymes.
  3. By using gibberellin and salicylic acid, the effect of possible chilling can be reduced at the beginning of the growing season.

Effect of Seed Priming with ZnSO4 and FeSO4 on Dormancy Break Optimization and Germination Traits of Shallot (Allium hirtifolium)
Elahe Hoseinpur Askarian, . Ali Abbasi Surki, Abdolrazagh Danesh Shahraki,
Volume 6, Issue 1 ((Spring and Summer) 2019)
Abstract


Extended Abstract
Introduction: In addition to dormancy, seeds of Allium hirtifolium have a weak emergence in the field. Among methods for improving the efficiency and emergence of seeds, nutritional priming can be considered for its performance on weak seeds. The presence of micronutrients is one of the factors that may affect the efficiency of the seeds. Therefore, the aim of this study was to investigate the effect of priming with nutrients on optimization of dormancy status, germination, and enhancement of shallot seeds for its conservational, restoration and domestication programs.
Materials and Methods: In order to study effects of nutrients on germination and emergence of Allium hirtifolium, a CRD factorial experiment was conducted with four replications at Seed Science and Technology Lab of Shahrekord University in 2015. Two dormancy breaking treatments (sulfuric acid and sulfuric acid + gibberellic acid) as the first factor and nine nutrition treatments including four levels of ZnSO4 (5, 10, 50 and 100 mM) and four levels of FeSO4 (0.5, 1, 1.5 and 2%) versus control were compared on shallot seeds.
Results: The results showed that dormancy breaking treatments, nutrient pretreatment of seeds and their interaction had significant effects on germination percentage, germination rate, time to reach l0% and 50% germination, germination uniformity, seedling length and vigor index I at 1% probability level. Sulfuric acid and FeSO41% increased germination versus control. Application of gibberellic acid affected the behavior of iron but did not indicate significant effects for zinc. The concentration of 5 mM ZnSO4 increased the rate of germination, compared with the control but decreased with higher concentrations. The gibberellic acid did not show any sharp effects on germination rate. Time to reach 50% germination was also affected by FeSO4 0.5% and 1% and lower levels of zinc. Application of gibberellic acid did not show any significant impact on the germination time reduction, compared with control and increased T50 in higher concentrations. Although germination traits were rarely affected by gibberellic acid, seedling length and vigor index were positively influenced with GA, and the highest seedling length was achieved at 0.5 and 1% of iron and gibberellic acid.
Conclusion: Seed priming with nutrients can improve germination and plant vigur indices. Different concentrations of iron and zinc showed different impacts on the seeds, which showed interaction with dormancy breaking methods. Although application of gibberellic acid did not have an effective role in increasing germination rate and reducing the time to reach 10% and 50% of germination, it enhanced seedling length and vigor index I, especially for iron.
 
 
Highlights:
  1. Addition of iron and zinc sulfate to shallot seeds whose dormancy was broken with sulfuric acid caused higher germination rate of  25.54%, compared with the control.
  2. Gibberellin compensated for zinc effect in germination and was able to replace it, but had a slight synergic effect with iron sulfate.
  3. Although gibberellin application did not affect germination traits, the seedling length and vigor index showed a positive response to it.

Effects of Plant Growth-Promoting Rhizobacteria on Germination and Early Growth of Alfalfa (Medicago sativa) under Salt Stress Conditions
Marzie Soltani Alikooyi, Ali Abbasi Surki, Mohsen Mobini Dehkordi, Shahram Kiyani,
Volume 6, Issue 2 ((Autumn & Winter) 2020)
Abstract



Extended Abstract
Introduction: Salinity is one of the most serious abiotic stresses, causing instability in germination and seed emergence due to low osmotic potential and ionic toxicity. Development of simple and low-cost biologic methods is essential for short-term management of salt stress. The use of plant growth-promoting rhizobacteria increases the rate and uniformity of germination. This research aimed to investigate the effect of bacterial growth-promoting bacteria on the germination and seedling growth indices of alfalfa c.v. Hamedani in different salinity levels.
Materials and Methods: A CRD factorial experiment with four replications was conducted in Seed Science and Technology Laboratory of Shahrekord University in 2016. The first factor consisted of 6 salinity levels 0, 2.5, 5, 7.5, 10 and 12.5 dS/m created with sodium chloride, and the second was four levels of bacterial pre-treatment: no inoculation with bacteria and biopriming, inoculation of alfalfa seeds with Acinetrobacter calcoaceticus PTCC 1318, Bacillus megaterium PTCC 1250 and Enterobacter aerogenes PTCC 1221. The seeds were treated with bacteria and placed at a 20 °C growth chamber. They were then irrigated with desired solutions depending on the salinity treatment. Germinated seeds were counted daily and the parameters of germination percentage and rate, seedling length, seedling dry weight, vigour index I, II and allometric coefficient were calculated after 10 days.
Results: Salinity levels higher than 10 dS/m reduced germination indices and seedling growth of alfalfa. The highest reductions were obtained for 12.5 ds/m salinity level versus control for germination percentage (10.81%), germination rate (49.48%), plumule and radicle length (13.30% and 28.88% respectively) and vigor index I and II, which were 30.27% and 6.28%, respectively. The seed treated with A. calcoaceticus was able to tolerate salinity stresses more than others. For example, the reduction for the seed treated with A. calcoaceticus was only 4%, compared with non-stressed control. In salinity conditions 2.5 and 5 dS/m, the highest rate of germination was obtained, using A. calcoaceticus bacteria. In addition, the seeds treated with E. aerogenes showed higher stability at different levels of salinity for seedling length traits. The highest vigour index related to the use of A. calcoaceticus in salinity was 7.5 ds/m.
Conclusions: A. calcoaceticus had a significant role in reducing the negative effects of salinity on germination percentage and rate, vigour index I and II and allometric coefficient while E. aerogenes bacteria were more effective in reducing negative effects of salinity on seedling length and dry weight.
 
 
Highlights:

  1. Acinetrobacter calcoaceticus bacterium increased the percentage and rate of germination of alfalfa seeds under salt stress.
  2. Enterobacter aerogenes bacteria efficiently adjusted the negative effects of salinity on alfalfa seedlings length and dry weight.

Improving the Emergence, Growth and Some Physiological Parameters of Canola (Brassica napus) by Leaching of Allelopathic Compounds of Soybean, Black Cumin, Dragonhead and Dill Residue
Marziyeh Rostami, Sina Fallah, Ali Abassi Surki, Mohammad Rafieoalhosseini,
Volume 7, Issue 1 ((Spring and Summer) 2020)
Abstract


Extended Abstract
Introduction: Plants release much of bioactive chemicals from different parts such as leaves, stems and roots through different mechanisms to their surrounding environement. These biologically active chemicals are often referred to as "allelochemicals". Allelopathic compounds play a major role in reducing germination and the growth of crops.
Materials and methods: In this study, the effect of leaching on the reduction of phytotoxicity effect of soybean, black cumin, dragonhead and dill was investigated on the emergence and early growth of canola (Brassica napus L.). The experiment was conducted as factorial based on a completely randomized design with four replications in 2016. Treatments included four previous crop residue (soybean, black cumin, dragonhead, and dill), and three levels of leaching (without leaching, one-time leaching, and two-times leaching). The leaching-free treatment (control) was sub-irrigated to maintain the uniformity of environment moisture. Five days after the first leaching, the two leaching treatment was irrigated again. Five days after the second leaching, when the soil moisture was suitable for seed planting, 10 seeds of canola were cultivated in each pot at a depth of 3 cm of soil. After three weeks seedlings of canola were removed from the pot and the traits were measured.
Results: The results showed that the growth characteristics of canola, except root length, were affected by the residues of the previous crop. In non-leaching conditions, the residue of the four plants reduced the rate and amount of canola emergence, and the greatest reduction in canola emergence was recorded for the application of black cumin residue (7.5%). In the leaching conditions, the length of canola leaves increased, which was higher in the twice leaching treatment. This trend shows that as the amount of leaching frequency increased, it is highly likely that more inhibitiing materials leave the soil and conditions become suitable for canola germination and growth.. The highest dry weight of canola root was observed in one-time leaching treatment. The dry weight of canola leaf grown in dill and soybean residues was increased as a result of one-time leaching, whereas the dry weight of canola grown in black cumin and dragonhead residues showed a higher increase in two-times leaching. Results show that four studied plants have canola growth inhibiting compounds and leaching can ameliorate this effect. The response of canola in the soil containing black cumin and dragonhead residues is higher in two-times leaching, and in the soil containing plant residues dill, one-time leaching is sufficient. In soils containing soybean residue, the response index was almost similar in case of one and two-times leaching.
Conclusion: Generally, the results showed that the application of leaching before planting canola reduced the inhibitory effects of plant residue on germination and growth of canola. Therefore, it is suggested that in the agricultural ecosystems in which canola is present in crop rotation, cultivation of canola must be avoided in presence of soybean, black cumin, dragonhead, and dill residue to eliminate their inhibitory effects on canola growth. In areas with water restriction, autumn rainfall can act as leaching and reduce the effect of allelopathic compounds. In case leaching is not possible, cultivation of canola inside the residue of these plants must be avoided.
 
 
Highlights:
1-Leaching can reduce the effect of allelopathic compounds.
2- Allelopathic compounds of some plants such as black cumin showed better response to two-times leaching.

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