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Showing 241 results for Type of Study: Research
Evaluation of Different Methods in Seed Dormancy Breaking and germination of Redroot Pigweed (Amaranthus retroflexus)
Vaghef Enayati, Ezatollah Esfandiari, Alireza Pourmohammad, Kamal Haj Mohammadnia Ghalibaf,
Volume 5, Issue 2 (3-2019)
Abstract



Extended Abstract
Introduction: Weeds, as the most important biological stress, reduce the efficiency of water use, waste of food, shading and secretion of toxic substances, leads to a 10 to 100 percent reduction in crop yields. The first step of the weed control understands the biology and life cycle of the weed particularly seed Eco physiological characteristics. Dormancy in weed seeds, including Redroot Pigweed seeds, is common. So, due to the importance of dormancy breaking and germination studies of weed seeds, the present study was designed to identify the methods for dormancy breaking and the germination of Redroot Pigweed seeds.
Materials and Methods: This research started in autumn 2013 by collecting Redroot Pigweed seeds from fields of Alajujeh village, Khoda Afrin County, East Azerbaijan Province, and then it was carried out at the Laboratory of the Faculty of Agriculture of the University of Maragheh in 2014 and 2015. For data analysis, the GenStat 12.1 program was used and the Duncan test was used at 5% probability level to compare the averages. Excel 2013 was also employed for drawing the diagrams.
Results and discussion: Analysis of variance demonstrated that the effect of treatments on germination percentage and germination rate in Redroot Pigweed seeds at 1% probability level and the mean germination time at 5% probability level was significant. The results showed that among studied treatments, seeds holding for 18 months were most efficient seeds dormancy breaking at Redroot Pigweed. So that the highest germination percentage (92%), germination rate (29.18 seed/day) and lowest the mean germination (4.2 day) time were obtained in seeds holding treatment. Pre-chilling treatment also had significant effects in stimulating germination. As regards treatments of seed holding in low temperature and Pre-chilling accelerate the germination process and increase germination percentage, so, having precise information of these traits enables to study, a better management and control of this troublesome weed.
Conclusions: In general, the results of this study show that among the treatments, holding seeds for 18 months at 6 ° C is the best method for solving Redroot Pigweed seeds weeds.

 
Highlights:
1- Seed holding in low temperature and Pre-chilling accelerates the germination process.
2- Seed holding in low temperature increases germination percentage.


Allelopathic Effects of Mustard (Sinapis arvensis) on Germination, Morphological and Biochemical Characteristics of Barley (Hordeum vulgare)
Yaser Alizadeh, Ehsan Zeidali, Hamid Hassaneian Khoshro,
Volume 5, Issue 2 (3-2019)
Abstract



Extended abstract
Introduction: Crop rotations are practiced to eliminate the effect of monoculture, but the succeeding crop may be influenced by the phytotoxins released by the preceding crop. Among plants, Brassica species contain allelochemical compounds as glucosinolate that is, under special conditions, released to environment and affects seed germination and plant growth. Wild mustard (Sinapis arvensis L.) as a weed of 30 crops in 52 countries which has a series of allelopathic effects that prevent germination of other plants. Products of glucosinolate- like ionic thiocyanate (SCN-) inhibited the root or shoot growth of many crop species. Also volatile compounds like isoprenoid and benzenoid released from Brassica tissue degradation may suppress many crops growth. It was also found in many studies that allelochemicals, which inhibited the growth of some species at certain concentrations, might stimulate the growth of same or different species at lower concentrations. The present research was conducted to evaluate the effects of aqueous extract concentration of various mustard parts on barley seed germination and seedling growth.
Materials and Methods: In order to evaluate the allelopathic effect of mustard in agro ecosystems, a factorial experiment based on completely randomized design with three replications was carried out in botany laboratory of agriculture faculty, Illam University in 2014. Experimental treatments included five concentrations of mustards foliage and root aqueous extract (0, 10, 30, 50, and 70 percent) that were studied at germination and early growth stage of barley (cv. Abidar) in two separate experiments. In the seed germination section, the effects of aqueous extract of mustard on germination rate and germination percentage of barley seed were measured. In the study of the effect of aqueous extract of mustard on barley seedlings, weight and length of root and shoot, leaf chlorophyll content, proline and soluble sugars content were measured.
Results: Results showed that the highest amount of barley seed germination percentage and germination rate (100 and 19.5, respectively) were observed in control and the lowest amount (40 and 9.5, respectively) belonged to mustard root aqueous treatment with 70 percent concentration. The most decrease in barley seedlings length and weight were observed at the highest concentration of aqueous extract. The amount of chlorophyll a decreased from 2.39 in control to 1.66 mg per fresh weight in 70 percent concentration of aqueous extract treatment. The highest amount of proline (66.8 μM per fresh weight) in barley foliage was observed in 70 percent aqueous extract treatment. The results from this study showed that mustard allelopathic effect may be a possible mechanism controlling the barley germination and early growth stage in agro ecosystems.
Conclusion: Generally, we were able to demonstrate short term auto toxicity and possible short-term allelopathy due to mustard has harmful effects on barley including reduced seed germination and emergence of barley seedling. Depending on the concentrations of Mustard extract, allelopathic activity will vary Mustard. Further investigations are also needed to determine the influence of cultivar variations, and to identify the active compounds involved in mustard auto toxicity and Allelopathy.
  
Highlights:
1-Mustards aqueous extract reduced seed germination percentage and plant growth in barley.
2-Mustards aqueous extract increased proline and soluble sugars in barley, but it reduced amount of chlorophyll in this plant.


Evaluating Hetrotoxic Potential of Aqueous Extract of Datura stramonium Shoots on Germination Traits and Content of Photosynthetic Pigments of Wheat Cultivars
Vahdat Rajaee, Ebrahim Gholamalipour Alamdari, Zeinab Avarseji, Masoumeh Naeemi,
Volume 5, Issue 2 (3-2019)
Abstract 


Extended abstract
Introduction: Nowadays exploitation of hetrotoxic characteristics  of hetrotoxic plants regarding  harmful effects of synthetic herbicides can most important role in weeds management and their control. In fact chemical compounds which is released by root, stem, leaf, flowers, seeds pollen, fruit and seeds can be used as bio herbicides and bio pesticides. The purpose of this srudy was evaluation of hetrotoxicity potential of Datura stramonium L. shoots on germination traits and photosynthetic pigments of wheat cultivars.
Materials and Methods: An experiment was conducted to evaluate hetrotoxicity potential of aqueous extract of different organs of Datura stramonium L. such as stem, leaf, fruit and mixed of them on germination traits and photosynthetic pigments of two cultivars of wheat (Kohdasht and N8720) as factorial experiment based on compeletly randomized design in three replications in Weeds Scince Laboratory of Gonbad-e- Kavous University in 2017. Datura stramonium shoot was collected at fruit formation stage in the Moghan plain and seprated into stem, leaf and fruit firstly. Five ml of studied extracts as well as mixed of them were added on 25 disinfected seeds of studied cultivars separately.
Results: Results showed that wheat cultivars had a different response to organs extract and this difference also were significant for various organs extract as well as interaction effect of cultivars in organs extract. Mean comparison of interaction of cultivars and organs showed that germination percent of Kohdash were decreased under experimental treatments. The highest decrease effect was obtained in the leaf extract about 98.33%. In return, stem, fruit and mixed organs had an increase effect on germination percent of N8720 about 5.72, 5.72 and 1.41% respectively. Result of the germination rate was similar with result of germination percent. Radicle and shoot length of both cultivars under experimental treatments were decreased. Leaf extract had an highest inhibition effect on radicle and shoot length about 96.70 and 89.21% respectively. Content of total chlorophyll of both cultivars of Kohdast and N8720 were increased under aqueous extract of stem (24.64%) and fruit (14.62%). Where as, extract of other organs and mixed of them had a decrease effect on studied trait. The result of carotenoid also was similar with result of total chlorophyll. Persumably, difference in allelochemicals concentration in various organs of Datura stramonium and physiological chracteractics of studied traits in cultivars caused different behavior.
Conclusions: According to the results, use of Datura stramonium biomass esspecially leaf, it is suggested as natural herbicides and strategy of non- chemical management. To accomplish this need to analyze phytochemical compounds of this weed.
 
Highlights:
  1. Extract of different parts of Datura stramonium weed had a different effect on germination traits and content of chlorophyll and carotenoids  of both cultivars of Kohdast and N8720.
  2. Leaf extract of Datura stramonium significantly decrease germination traits and content of chlorophyll and carotenoids of Kohdasht cultivar seedlings.
3- Use of Datura stramonium can be a good option for appearance of natural herbicides.

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 (3-2019)
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 Growth Promoting Bacteria and Salicylic Acid on Melon (Cucumis melo) Seed Germination and Seedling Growth under Salt Stress
Hossein Nastari Nasrabadi, Mehdi Moradi, Mohammad Naser Modoodi,
Volume 5, Issue 2 (3-2019)
Abstract


Extended abstract
Introduction: Using of plant growth regulators is one of the methods can improve plant growth against environmental stresses such as salinity. Salicylic acid plays an important role in physiological processes regulation, including germination. Today, using of growth promoting bacteria has been increased and it causes to raise the seed vigor, uniformity, germination percentage and better seedling establishment. Growth promoting bacteria can be effect on increasing plant resistance to adverse environmental conditions by interposition in plant hormones production such as auxin, GA, cytokinins, and as well as the stabilization of nitrogen or phosphorus availability and other nutrients
Materials and Methods: This experiment was conducted as factorial in a completely randomized design with three replications. Salicylic acid factor (SA) was selected at two levels (0 and 1 mM). The bacterial treatments included Azotobacter (AZ), Azospirilum (AZP), complex of Azotobacter and Azospirillum (AZ + AZP), and without inoculation (C) and salinity treatment (S) was at five levels (0, 50, 100, 150 and 200 mM).
Results: Results showed that all treatments had no significant effect on germination percentage. Radicle and plumule length, seed vigor index and seedling fresh weight was significantly increased at 50 mM NaCl. Generally speaking, the elongation of plant organs when treated with low concentrations of salts may induce osmotic adjustment activity in the plants which may improve growth. Germination rate, Radicle and plumule length and seed vigor index were significantly increased by salicylic acid treatment. AZ and AZ+AZP increased germination parameters significantly than control. Generally germination factors were better improved by combination salicylic acid with AZ than AZP and AZ+AZP. These results could indicate the synergistic relationship between growth promoting bacteria and salicylic acid.
 Conclusion: According to the results pre-treatment of melon seeds by 1 mM salicylic acid and Azotobacter can be proposed to improve seed germination and seedling establishment under salinity stress.

 
Highlights:
  1. Effect of salinity on seed germination characteristics of melon.
  2. Effect of biofertilizer and salicylic acid on germination and seedling growth of melon under salt stress.

Comparison of Different Models for Determining Time up to 50% Maximum Germination: A Case Study of Cottonseeds (Gossypium hirsutum)
Farnaz Porali, Farshid Ghaderi-Far, Elias Soltani, Mohammad Hadi Palevani,
Volume 5, Issue 2 (3-2019)
Abstract


Extended abstract
Introduction: Germination speed is one of the most important germination indices, used in most studies to compare the effects of different treatments on seed germination. Researchers use the reverse time up to 50% maximum germination (1/D50) to calculate the germination rate. One of the methods used for calculating the D50 is the utilization of nonlinear regression models such as Logestic, Gompertz, Richard, Weibull and Hill. In addition, for the purpose of calculating this parameter, simple empirical models such as the model presented by Farooq et al. and Ellis and Roberts are used. The question which arises is which of these methods has more precision predicting D50. The purpose of this study was to calculate D50, using different methods in seed germination of cotton.
Material and Methods: In this experiment, cottonseeds were placed at three temperatures of 15, 25 and 40°C with three replications, and germinated seeds were counted daily several times. To calculate D50, several nonlinear regression models including Gompertze, Logestic, Hill (the four-parameter), Richard and Weibull models were used. Moreover, for the purpose of calculating D50, the models presented by Farooq et al. and Ellis and Roberts were used.
Results: The results showed that all nonlinear regression models exhibited suitable fit to germination data. However, logestic, Hill and Weibull showed better predictability of D50, compared with other models. Besides, D50 calculated by the Farooq model was similar to that estimated by nonlinear regression models, whereas D50 estimated by the Ellis and Roberts model was higher than that estimated by other models.
Conclusions: The results of this study showed that both non-linear regression models and the model developed by Farooq could be used to calculate D50 of cottonseed. In general, the results of this study showed that nonlinear regression models could be used to calculate D50. In this research, Logestic, Hill, and Weibull showed good fit for cumulative seed germination data of cotton seeds versus time at different temperatures. These models have coefficients that have a biological concept that includes maximum germination percentage, time to 50% maximum germination and time to start germination. Moreover, when researchers only seek to measure D50 and are not familiar with the statistical software, they can use the empirical formula presented in this research.
 
Highlights:
  1. Calculating D50 in cottonseeds, using different methods.
  2. Using nonlinear regression models to calculate D50 in cottonseeds.
  3. Developing a proper method which is more accurate, and better lends itself to calculating D50 of cottonseeds.

Effect of Seed Aging and Water Potential on Seed Germination and Biochemical Indices of Fenugreek (Trigonella foenum-graecum) at Different Temperatures
Hasan Teimori, Hamidreza Balouchi, Ali Moradi, Elias Soltani,
Volume 5, Issue 2 (3-2019)
Abstract


Extended abstract
Introduction: Seed germination is one of the first important and complex stages in the plant life cycle and is affected by many hereditary and environmental factors. Various factors affect germination and seedling establishment. Among these factors are the characteristics of the maternal plant (nutrition, genetics), seed treatment stage at harvest time, as well as environmental factors (temperature, water potential, and ventilation and soil compaction). Also, under the influence of seed loss during storage, seed vigor, which is known as the first component of seed quality, decrease. The aim of this study was investigation of germination and biochemichal responses of the aged seed of Fenugreek to different temperature and humidity ranges.
Materials and Methods: This experiment was conducted as a factorial based on a completely randomized design with four replications in the Laboratory of Seed Science and Technology, Faculty of Agriculture, Yasouj University in 2016. The experimental treatments consisted of nine levels of temperature (5, 10, 15, 20, 25, 30, 35, 40 and 45 degrees Celsius), water potential included seven levels (zero (control), -0.2, -0.4, -0.6, -0.8, -1 and -1.2 MPa) and seed aging at two levels (no aged (control) and aged seed).
Results: In this experiment, the effect of seed aging, water potential and their interactions on each environment on germination indices (germination percentage and germination rate, length and weight vigor index) and biochemical indices (soluble sugar, proline, soluble protein and catalase enzymes) of Fenugreek seeds were significant. The results showed that in the aged seed the germination percentage and rate and seedling vigor index tended to decrease with water potential reduce in temperature lower and higher than 20 degrees Celsius, and the amount of biochemical components of the seed (soluble sugar, soluble protein, proline, and catalase enzyme) also increase.
Conclusion: In general, germination and biochemical indices of seed of Fenugreek are sensitive to water potentials, aging, and seed germination temperatures, respectively. In terms of osmotic potential decrese, the germination temperature of less than 20 ° C resulted in increased germination resistance of fenugreek seed to a more negative water potential.
 
Highlights:
  1. Study of germination and biochemical properties of fenugreek seed aged under different level of osmotic potantials and temperatures.
  2. In areas with a lower osmotic potential it is better to cultivate Fenugreek seed at temperatures below 20 °C.

Effect of Gibberellin and Salicylic Acid on Tolerance of Pumpkin (Cucurbita pepo) Seedling
Maryam Mokhtari, Sina Fallah,
Volume 6, Issue 1 (9-2019)
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.

The Effect of Seed Inoculation with Organic and Biologic Fertilizers on Germination and Heterotrophic Seedling Indices in Rainfed Wheat (Triticum aestivum) Cultivar
Narjes Hojati Fahim, Mohamad Sedghi, Mehrdad Chaeichi, Rraouf Seyed Sharifi,
Volume 6, Issue 1 (9-2019)
Abstract


Extended Abstract
Introduction: Iran is located in the arid and semi-arid regions of the world with an average rainfall of 240 mm per year, which requires rethinking of the adoption of methods. One of the alternative ways is to use organic and biological fertilizers. Biological fertilizers are considered as the main and the most important factor in the integrated management of plant foods for sustainable agriculture as they play an important role in product improvement and efficiency. Therefore, this research was carried out with the aim of investigating the effect of seed pre-treatment with some organic and biological fertilizers in rainfed wheat.
Materials and Methods: A factorial experiment with three replications was conducted at the Laboratory of Seed and Plant Certification and Registration of the Center of Agriculture and Natural Resources Research located in Hamedan. Seed inoculation was considered in 5 levels (Seafull, Disper Root Gs., Bio-Health, Trichodermin and control) on 8 different rainfed wheat cultivars (Azar-2, Hashtrood, Baran, Rasad, Owhadi, Sardari, Takab and Homa). First, the seeds were disinfected with sodium hypochlorite, and were then cultured in special containers and were placed in the germinator at 20 ° C. After 4 and 8 days, the number of germinated seeds was counted. Germination seeds were counted in each treatment and germination indices such as germination rate, average daily germination, coefficient germination rate, longitudinal vigor index, weight vigor index, seedling fresh weight, root length/shoot ratio, shoot fresh weight, root fresh weight, seed reserve utilization rate, seed reserve utilization efficiency, fraction utilization seed reserve, seed dry weight were calculated.
Results: With application of different levels of fertilizer, the rate of germination treatment Homa×Bio-Health (155%), average daily germination treatment Hashtrood×Bio-Health (69%), coefficient germination rate treatment Owhadi×Disper Root Gs (60%), longitudinal vigor index treatment Owhadi×Bio-Health (108%), weight vigor index treatment Homa×Bio-Health (64%), root fresh weight treatment Hashtrood×Disper Root Gs (106%), shoot fresh weight treatment Hashtrood×Seafull (23%), seedling fresh weight treatment Homa×Bio-Health (42%), root length/shoot ratio treatment Owhadi×Trichodermin (75%), seed reserve utilization rate treatment Homa×Bio-Health (118%), and fraction utilization seed reserve treatment Homa×Bio-Health (119%) increased, compared with the control. In addition, the application of Bio-Health fertilizer and Hashtrood cultivar had the highest amount in almost all the mentioned attributes
Conclusion: Investigation of the different levels of fertilization showed that in most of the indices related to germination and heterotrophic growth of seedling, pretreatment with Bio-Health biofertilizer had a significant difference with other fertilizer levels.
 
 
Highlights:
  1. Evaluation of germination indices for recent cultivars of rainfed wheat, released by rainfed Research Institute of Iran.
  2. Investigating and comparing fertilizers with various multifactorial compounds (fungi and bacteria) and with each other.
  3. Conducting research on commercial compounds and comparison of live biochemical and non-organic matters in a single experiment.

Effects of TiO2 Nanoparticles on Germination and Primary Growth of Mountain Ash (Sorbus luristanica)
Vahid Sayedena, Babak Pilehvar, Kambiz Abrari-Vajari, Mehrdad Zarafshar, Hamid Reza Eisvand,
Volume 6, Issue 1 (9-2019)
Abstract


Extended Abstract
Introduction: Production of nanoparticles and their use are on the rise in different areas of plant science. However, in spite of their increasing production, there is limited information about their effects on plant biology. In the current study, the potential of TiO2 nanoparticles was investigated for the purpose of improving seed germination of Sorbus luristanica and then subsequent effects of nanoparticles on the growth and biomass of the plants were determined.
Materials and Methods: Seeds of S. luristanica were collected from its natural stands. The seeds were primed with different concentrations of 0, 75, 150, 250, 350 and 500 TiO2 nanoparticles miligeram per liter for 24 h. The treated seeds were placed in wet sand at room temperature for 2 weeks and then in cold for 3 months. The expriment was set as a completely randimized design with 4 replications. Aftre 3 months of stratification in moistened sand, the stratified seeds were put in the germinator and with the appearance of seed germination signs, germination data were recorded daily during 22 days. At the end of the seed germination experiment, some germination parameters such as seed germination percentage, seed vigority and mean time to germination were calculated. Moreover, some growth and biomass parameters including leaf number, plant height and dry and fresh biomass of leaf, stem as well as roots were measured. In addition, scaning electron microscopic (SEM) was used for observation of presence and adhesiveness of TiO2 nanoparticles on the seed coat.
Results: Based on the results, all the germination parametres including seed germination percentage, seed vigoroty and mean germination time were improved by the TiO2 nanoparticles treatments. In addition, 500 mg.L-1 treatment considerably improved seed germination characteristics. The peresence of TiO2 nanoparticles on the treated seeds and lack of the nanomatreials on the conrtol seeds were obsereved by scaning electron microscopic pictures. The One-way ANOVA showed that 75 mg.L-1 treatment was more succesful for improving the grwoth (such as shoot length) and biomass production (fresh and dry biomass of leaf, stem and root and total biomass as well).  
Conclusion: It can be concluded that priming of the seeds of this species with different concentrations of TiO2 nanoparticles leads to improvement of seed germination and growth and biomass parameters. However, the patterns of effects were different in each phase. Therefore, the objectives should be formulated first and then the best concentration should be chosen. It seems that with appropriate concentrations, nanoparticles can be useful for breaking seed dormancy and production of the species. Given the promising resutls of 150 mg.L-1 treatment, it can represent a successful treatment for breaking seed dormancy and seedling production of S. luristanica.
 
 
Highlights:
1- Study of seed germination of Sorbus luristanica for the first time
2- Using Nano-materials and their potentials in breaking seed dormancy and improving the species germination
3- Using SEM in order to study presence and adhesiveness of nanoparticles on the seed coat
Evaluation of the Allelopathic Potential of Some Weeds on Germination Characteristics and Photosynthetic Pigments of Cress Seedlings (Lepidium sativum)
Ebrahim Gholamalipour Alamdari, Rashid Poornamazi, Abbas Biabani, Fakhtak Taliey,
Volume 6, Issue 1 (9-2019)
Abstract


Extended abstract
Introduction: Interference includes competition for environmental potentials and allelopathy. By releasing chemical compounds, usually of secondary metabolites, in various ways such as root exudation, decomposition, leaching and volatilization, allelopathic weeds may have positive, negative or even neutral effects on crops. Therefore, the purpose of this experiment was to evaluate the hetrotoxic potential of Sorghum halepense, Portulaca oleracea and Centurea depressa in characteristics of germination, chlorophyll content and carotenoid pigments of cress under laboratory conditions.
Materials and methods: For bioassay experiments, various concentrations of 0, 20, 40, 60, 80 and 100% of the weeds such as S. halepense, P. oleracea and C. depressa were prepared with the help of distilled water and were subsequently separately applied on 50 certified seeds of cress. In this experiment, characteristics such as rate and germination percentage, content of chlorophyll a, b, total chlorophyll content and carotenoids were measured based on the chilled acetone method.
Results: Regression model showed that rate and germination percentage of cress significantly decreased at concentrations higher than 80% of S.halepense only. For every unit increase in the concentration, radicle length, seed vigor, content of total chlorophyll and carotenoids of cress decreased about 0.08 cm, 8.68, 0.007 mg/g and 0.007 mg/g, respectively. According to the results, there was an exponential relationship between different concentrations of the P. leracea extract with germination characteristics and photosynthesis pigments of cress so that in most cases, these characteristics up to concentration of 40% had moderate decline, but beyond this concentration, they showed a steep decline. In case of C. depressa, rate and germination percentage, as well as the shoot length of cress decreased about 14.67, 14.67 and 29.81% respectively, using only a concentration of 100%. However, radicle length and seed vigor of cress decreased with increased concentrations of aqueous extract of C. depressa. The most reductive effects were obtained in the treatment of 100%, which were about 52.38 and 55.44% respectively. Amount of total chlorophyll of cress decreased about 14.37, 27.59 and 25.29% respectively in concentrations of 60, 80 and 100% of C. depressa extract, as compared with the control. On the other hand, concentrations of 20 and 40% of C. depressa had no significant effect on the pigment studied. The result of carotenoids content was the same as total chlorophyll.
Conclusions: Based on the results, the weeds studied, especially P. oleracea, with high concentrations, had strong hetrotoxic effect on germination characteristics and photosynthesis pigments. This requires further investigation in a natural environment where targeted plants grow in close proximity.
 
 
Highlights:
  1. Hetrotoxic compounds of Portulaca oleracea, especially in high concentrations significantly decrease seed germination and photosynthetic pigments of cress as compared with Sorghum halepense and Centurea depressa.
  2. Given the evidence for the hetrotoxic effect of aqueous extract of the weeds studied, they could be introduced as candidates for production of bio-herbicides.

Quantification of the Best Harvest Time of Guar (Cyamopsis tetragonoloba) Seed with High Quality in Golestan Province
Mahsa Nazer, Seyed Mohammadreza Ehteshami, Masoumeh Salehi, Ali Kafighasemi,
Volume 6, Issue 1 (9-2019)
Abstract

Extended Abstract
Introduction: Guar (Cyamopsis tetragonolob) which belongs to fabaceae and leguminosae families is self-pollinating and is indigenous to India and Pakistan. This plant is suitable for growth in dry, damp and sandy soils, and can tolerate saline and relatively alkaline soils. Determining the best time for harvesting seeds and its timing with maximum quality is one of the important issues in the field of seed production management. The changes in the physiological quality of seeds occur during development until seed treatment. The use of high-quality seeds plays an important role in the final yield of crops. The purpose of this study was to determine the most suitable time for harvesting seeds because seed moisture content at harvest time is one of the most important factors affecting seed quality.
Materials and Methods: This research was carried out in July 2013 at Iraqi Research Station in Gorgan, Golestan, Iran in a split-plot design with four replications. The treatments consisted of the time of harvesting the seeds from the mother's base in six stages (with different moisture content) and harvesting places (upper, middle, and bottom pods) so that, starting from the podding, every 7 days, the seeds were removed from the base. The mother was harvested and such traits as germination rate, germination percentage, seedling vigor, seed moisture content, and alpha-amylase activity were calculated. In this research, a logistic model was used to study the changes in germination percentage, germination rate, seedling vigor index and straw index during seed dressing on Guar.
Results: The results of this study showed that the hypothesis that seed reaches its maximum quality at the end of the period of seed filling is confirmed, suggesting that with a moisture content of 30 and 14% in late seed filling period, Guar seeds have the highest quality. In general, the results of the present study confirm that the stages of development and management of Guar seeds on maternal basis have an impact on its quality. In the early stages of growth (humidity 85, 80 and 62 percent), due to prematurity and lack of essential seed structures, the qualitative traits of germination percentage, germination rate, seedling vigor, and strawberry index were low, and with the evolution of essential structures and reduced seed moisture content (58, 30 and 14%), the quality traits increased.
Conclusions: In general, it can be concluded that the best timing for harvesting Guar seeds with the highest quality in Golestan province is when seed moisture reaches 14% or 100 days after planting, and the pods formed at the bottom are the ones with the highest quality.
 
 
Highlights:
  1. To investigate the qualitative indices of Guar seed on the mother plant during seed filling period
  2. To determine the best harvest time and its adaptation with the highest quality of Guar seed

Impact of Storage Fungi on Soybean Seed Deterioration in Different Storage Conditions and Seed Moisture Content
Saman Sheidaei, Aidin Hamidi, Hossein Sadeghi, Bita Oskouei, Leila Zare,
Volume 6, Issue 1 (9-2019)
Abstract


Extended Abstract
Introduction: Understanding the complex characteristics that control the life span of the seed has ecological, agricultural and economic importance. Inappropriate storage conditions after harvesting destroy a large part of annual yield partly due to microbial activity in the storage. Damage from storage fungi varies based on the climatic conditions, crops and storage facilities. This study was carried out to investigate the effect of storage conditions and initial seed moisture content on the growth of storage fungi and also the relationship between the degree of contamination with fungi and the quality and biochemical changes of the seeds.
Materials and Methods: The present study was carried out as a factorial experiment based on a completely randomized design to assess the impact of storage fungi on soybean seed deterioration at different storage conditions. The treatment included three degrees of initial seed moisture content including low moisture content (10%), medium moisture content (12%) and high moisture content (14%) as the first factor. Moreover, two storage conditions including the seed storage in Moghan and controlled seed storage in Seed and Plant Certification and Registration Institute were considered as the second factor. Soybean seeds of Williams's cultivar were investigated for the infection of Aspergillus flavus, Aspergillus niger, Fusarium and Penicillium fungi and also related biochemical traits and seed quality such as germination percent, seedling vigor index, soluble sugar and total protein.
Results: The results of this experiment showed that the increase of the seed moisture content by 14% can significantly decrease the seed quality. Therefore, the seed moisture content of 14% was identified as unsuitable moisture for the storage of soybean seeds. In addition, the infection with storage fungi has a direct relationship with the degree of seed moisture and seeds with high moisture content are rapidly attacked by the storage fungi which can decrease seed quality and viability. Moreover, the Aspergillus niger infection increased from 27.5 to 43.75 and the germination percent decreased from 52.5 to 23 percent in seeds with a moisture content of 14% in Moghan storage, as compared with the controlled storage. Furthermore, this study showed that when the percentage of storage fungi increases, the soybean seed deterioration increases. Studying the biochemical changes of deteriorated seeds during the storage showed that as the aging of the seeds increases, soluble sugars and protein percentage decrease. The amounts of soluble sugars and total protein of the seed were significantly lower in seeds maintained under unsuitable conditions. Furthermore, the content of soluble sugars and total protein decreased significantly by the increase of the seed moisture, which resulted in the increase in seed deterioration.
Conclusions: Based on the obtained results, initial seed moisture and storage conditions are two important determinants of fungi infestation during storage, which can affect the content of soluble sugars and total protein causing seed deterioration, seed vigor and viability. It can be concluded that the soybean seed moisture content of 12%, which is the standard moisture content of soybean seed production in Iran, is regarded as suitable moisture for seed storage.
 
 
Highlights:
  1. Introduction of proper storage conditions and initial seed moisture in order to decrease fungal damage and soybean seed deterioration.
  2. Determination of different fungal damages during the storage of soybean seeds.
  3. Determination of relationship between the degree of soybean seed infection of storage fungi and the seed’s quality, its amount of protein and soluble sugars.

Investigation of the Effect of Salinity and Drought Stress on Germination Characteristics of Strangle Wort (Cynanchum acutum) Seeds
Habib Nejadgharebaghi, Esfandiar Fateh, Amir Aynehband,
Volume 6, Issue 1 (9-2019)
Abstract


Extended Abstract
Introduction: Strangle wort (Cynanchum acutum) is a perennial weed that could be propagated by seeds and vegetative organs. This brings about harvesting problems for some crops such as cotton, sugar beet, wheat and maize. In recent years, this weed has caused huge losses in sugar cane fields. The role of environmental conditions in weed management is highly important. Given this, the present study seeks to investigate the effects of environmental conditions (salinity and drought stress) on germination characteristics of strangle wort weed.
Materials and Methods: In order to investe the effect of different salinity and drought levels on strangle wort (Cynanchum acutum), two seperate experiments were conducted at Hakim Farabi Khuzestan Sugar Cane Research Institute in 2014-2015. The experimental design was completely randomized, with four replications. The treatments were different salinity levels at 8 levels (0, 2.5, 4.5, 6.5, 8.5, 12.5, 16.5 and 20.5ds/m) and the second experiment involved different drought stresses (osmotic potential) at 7 levels (0, -1, -3, -6, -9, -12 and -15 bar).
Results: The results of salinity stress experiment showed that with increases in salinity levels from 0 to 20.5 ds/m, germination, radicle length, plumule length and seedling weight decreased by 61, 80, 91 and 99%, respectively. The results of drought stress experiment showed that with increases in salinity levels from 0 to -15 bar, all studied traits, i.e., germination, radicle length, plumule length and seedling weight all decreased by 100%.
The analysis of variance results showed that in all the traits, there were significant differences between salinity and drought stress in 1% probability level. In this research, in the salinity experiment, in most of traits, especially radicle length quickly decreased after 8.5 ds/m salinity to higher levels and in drought stress experiment, after -3 bar to higher levels.
Conclusion: On the whole, it seems that sufficient information about this weed is vital for the adoption of the best control method, and gaining insights into how strangle wort responds to environmental stress, especially salinity stress, could help us to come up with new control approaches for this invasive weed. This can present a proper ecological approach that could be adopted in sustainable agriculture programs, which is environmentally sound as it decreases the use of chemical inputs. In addition, in order to lower the tolerance of this weed to salinity and especially drought stress, it is suggested that it be used for weed management programs. According to the results of this study, soil salinity higher than 8.5 ds/m and drought tension above than -3 bar can cause sizeable reduction in most traits (growth parameters) especially in root length. In most of the traits scrutinized, the tolerance of the weed to salinity and drought stress was 12.5 ds/m and -6 bar, respectively.
 

 
Highlights:

  1. Evaluation of germination characteristics of strangles wort under salinity and drought stress conditions.
  2. Determination of tolerance threshold of strangles wort germination seed to salinity and drought stress.

Effect of Planting Pattern and Irrigation Method on Germination of Mung Bean (Vigna radiate) Harvested at Different Times of Maturation
Ashraf Alizadeh-Amraie, Abdollah Javanmard, Hamdollah Eskandari,
Volume 6, Issue 1 (9-2019)
Abstract

Extended Abstract
Introduction: Pulses are a group of crops which are important in human nutrition and also sustainability of agronomical systems and economic advantage. Regarding optimum planting density of mung beans (40 plant m-2), more than 700 tons of certified seeds of mung bean seeds are needed all over the country, confirming the importance of the production of high quality seeds. Seed quality may be affected by different environmental conditions such as water deficit. Since intercropping can alleviate the negative effects of drought on crop growth, the hypothesis that crops can benefit from intercropping has been formulated in previous studies. Since there is no sufficient information on germination performance and seed weight of mung bean during seed growth and development in response to partial root zone irrigation and intercropping, the current experiment was aimed to evaluate the effect of partial root zone irrigation and intercropping on some quality traits of mung bean and to determine the best time of harvesting to produce high quality seeds in mung bean.
Materials and Methods: The experiment was conducted as factorial (3× 2× 5) based on RCBD with three replications. The first factor was planting pattern (including sole mung bean, inter-row maize-mung bean intercropping and within-row maize-mung bean intercropping). The second factor was irrigation method (partial root zone irrigation and conventional irrigation) and the third factor was harvest time (5-day intervals in 5 stages). Germination percentage, 1000-grain weight, root length, shoot length and seedling dry weight were determined for evaluation of seed quality.
Results: The results indicated that the interaction of cropping pattern× harvest time and cropping pattern× irrigation× harvest time had no significant effect on traits. However, the interaction of irrigation× harvest time on germination percentage, root length and seedling dry weight was significant (P≤0.01). With increasing growth and maturation of seed, germination percentage increased in both irrigation methods. Germination percentage of mung bean was reduced by partial root zone irrigation. The effect of partial root zone irrigation on germination percentage was higher at the end of seed filling period. Partial root zone irrigation resulted in the reduction of root length. The differences between conventional and partial root zone irrigation for root length at different harvest times were 4, 9, 9, 18 and 15 percent, respectively. In both irrigation methods (i.e., conventional and partial root zone irrigation) seedling dry weight increased with increasing the seed growth and maturation. However, deficit of irrigation had negative effects on seedling dry weight of mung bean. With reduced water availability, 1000-grain weight and shoot length were also reduced. 1000-grain and shoot length of mung bean in conventional irrigation were 11 and 10 percent higher than those of partial root zone irrigation, respectively.
Conclusion: Intercropping had no significant effect on seed quality of mung bean. However, deficit of irrigation reduced its seed quality. For harvesting high quality seeds in mung bean, there is a need for plants that experience no drought stress. That the time of reaching the maximum seed quality coincided with the ending of the seed filling period confirms the Harington’s hypothesis.
 
 
Highlights:
  1. Seed quality of mung bean during seed growth and development was evaluated.
  2. Effect of deficient irrigation induced by partial root zone irrigation on seed quality of mung bean was determined.
  3. The effect of planting pattern of mother plants on seed quality was investigated.

Effect of Temperature and Light on Germination Characteristics of Japanese Morning Glory (Ipomoea nil): Determination of Cardinal Temperatures of Germination
Hosein Sarani, Ebrahim Izadi, Ali Ghanbari, Ali Rahemi,
Volume 6, Issue 1 (9-2019)
Abstract


Extended Abstract
Introduction: In recent years, Japanese morning glory has been recognized as a new weed in some soybean cultivation areas in the Province of Golestan. Japanese morning glory, an annual herbaceous plant, belongs to Convolvulaceae family. Germination is the first step in the competitiveness of a weed in an ecological niche. Among the factors influencing seed germination, temperature and light are the most important environmental factors. The relationship between temperature and germination rate is mainly determined by nonlinear regression, and various models such as dent-like, segmented, beta, and second-order major models are used for this purpose. In this study, we examined the aspects of germination biology of this weed under the influence of temperature and light.
Materials and Methods: In order to investigate the effect of temperature and light on germination of Japanese morning glory, two separate experiments were conducted. Treatments included constant temperature at 7 levels (10, 15, 20, 25, 30, 35, 40) in the first experiment and alternating temperature at 6 levels (30/25, 10/15, 30/20, 35/25, 40/30, 45/35) and light conditions (14 hours of brightness 250 μmoles/m-2-sec-1) and darkness in the second experiment based on a completely randomized design with four replications. The number of germinated seeds was taken up to 4 days after stopping germination every day. Percentage and speed of germination and time reaching 50% germination were calculated. Three models of dent-like, segmented lines and beta were used to determine the cardinal temperature between the temperature and germination rate.
Results: The results showed that temperature had a significant effect on percentage, speed and time taken to reach 50% (D50) of germination of Japanese morning glory. The highest percentage of germination (95%) and germination rate (19.80 seeds per day) were observed in the alternating temperature of 20/30 ° C treatment, respectively. The lowest percentage of germination (83.33%) was observed at alternating temperatures 25/35 °C, and the lowest germination rate (15.10 seeds per day) was observed at 10-20 °C. The segmented lines, dent-like and beta were best fit based on the highest R2adj 0.95, 0.96 and 0.95, respectively. Light had no significant effect on germination, so that germination occurred under both light and dark conditions. According to the results, Japanese morning glory is able to germinate at a wide range of constant and alternating temperatures, although germination is faster at warmer temperatures. On the other hand, the lack of light for germination is another advantage that increases germination, competition, and expansion in agronomic environments.
Conclusion: The findings of the present study suggest that the highest percentage of germination and rate of germination were observed in alternating temperatures of 20/30 °C respectively. Among the nonlinear regression models, the dent-like model represented the best model for describing the germination rate against the temperature in Japanese morning glory. It seems that this weed has better germination at warmer temperatures. Probably from mid-spring following warmer weather, and upon the availability of water, this weed is in a good situation to germinate and compete. It was also found that light had no significant effect on the germination of this weed.

Highlights:
  1. Non-photoblastic seeds
  2. Superiority of dent-like model for predicting germination of Japanese morning glory

Aqueous Extract Effect of Different Organs of Malva sylvestris Weed on Germination Characteristics and Photosynthetic Pigments of Echinochloa crus-galli
Mahnaz Tatari, Ebrahim Gholamalipour Alamdari, Zeinab Avarseji, Mehdi Zarei,
Volume 6, Issue 2 (3-2020)
Abstract



Extended abstract
Introduction: Due to their aggressive and competitive habits, weeds inhibit the growth of valuable plants. Interference in plants includes environmental competition and allelopathy (Autotoxicity and hetrotoxicity). In hetrotoxicity, chemical compounds released from plants are able to effect the neighboring plants. Proper management of weeds and the exploitation of their hetrotoxicity potential can reduce losses caused by weeds. This could also represent an effective step towards the reduction of the use of herbicides. Therefore, the purpose of this study was to evaluate the effect of hetrotoxicity potential of aqueous extract of various organs of Malva sylvestris L. weed on traits of germination and photosynthetic pigments of Echinochloa crus-galli L.
Material and Methods: An experiment was conducted to evaluate the effect of hetrotoxicity potential of aqueous extract of Malva sylvestris  L. weed including the stem, leaf and flower as well as their mixture on traits of germination and photosynthetic pigments of Echinochloa crus-galli L. as a completely randomized design in three replications in Weeds Science Laboratory of Gonbad Kavous University in 2017. For this experiment, aerial parts of M. sylvestris were first collected at the flowering stage from Ramian field. They were subsequently separated with great care and were powdered. Then from them, 5% suspensions (weight/volume) were prepared, using distilled water. Finally, the extract of each organ of M. sylvestris was added to Petri dishes containing E. crus-galli seeds. After the 7th day, traits such as rate and percentage of germination, radical and shoot elongation, vigor index, total content of chlorophyll a and b and carotenoids were measured.

Results: The results showed that various organs of M. sylvestris and their mixture had different inhibitory effects on traits of germination and seedling length of E. crus-galli weed. The highest inhibition effects on rate and germination percentage and elongation of radical and shoot of E. crus-galli were obtained using leaf extract of M. sylvestris about 64.04, 64.37, 87.69, 62.81%. In this study, radical length is more affected under hetrotoxic compounds of various organs of M. sylvestris, as compared with shoot length. Based on the results, various organs of M. sylvestris and their mixture also have different inhibitory effects on chlorophyll and carotenoid content of E. crus-galli weed. It seems that the differential effects among different organs of M. sylvestris are a function of the threshold concentration of allelochemicals to hetrotoxic compounds of the organs, which causes various response by E. crus-galli.
Conclusion: Given the evidence for the effect of hetrotoxicity potential of various organs of M. sylvestris on traits of germination and pigments of chlorophyll and carotenoid of E. crus-galli and huge biomass generated, it is advisable to exploit allelochemical compounds of this plant as bio-herbicides.
 

 
Highlights:
1- Study of the the effect of hetrotoxic potential of Malva sylvestris weed on germination characteristics and photosynthetic pigments of Echinochloa crus-galli in Ramian field.
2- E. crus-galli weed exhibits great sensitivity to hetrotoxic compounds of various organs of M. sylvestris,  especially the leaves.
3- Allelopathic characteristics of M. sylvestris weed have huge potentials for the production of bio-herbicides.


Effect of Stevia (Stevia rebaudiana) Seed Priming Treatments with Salicylic Acid, Iron, and Zinc on Some Germination Traits and Photosynthetic Pigments under Drought Stress
Alireza Gorzi, Heshmat Omidi, Abdolamir Bostani,
Volume 6, Issue 2 (3-2020)
Abstract


Extended abstract
Introduction: Stevia (Stevia rebaudiana Bert.) is a herbaceous perennial plant that belongs to the family of Asteraceae. Stevia is a self-incompatible herb and the seeds resulting from this plant have low germination ability. Steviol glycosides found in this plant are 250-300 times sweeter than sucrose and despite their sweet flavor; they are not absorbed by the body. In general, the poor germination capacity of Stevia seeds is a major impediment for its large-scale cultivation. Priming is one of the seed enhancement techniques that could lead to an increase of germination percentage and germination rate under stress conditions. Therefore, the present study was conducted to evaluate the impact of priming with salicylic acid (SA), iron (Fe) and zinc (Zn) on some germination indices, seedling growth as well as the content of photosynthetic pigments in Stevia under normal and drought stress conditions.
Materials and methods: A factorial experiment using a completely randomized design was carried out in the Seed Science and Technology Laboratory of Agricultural College, Shahed University, in 2017. The factors studied comprised four levels of drought stress (0, –0.3, –0.6 and –0.9 MPa) and seven priming combinations with SA, Fe and Zn. Non-primed seeds (dry seeds) were also considered as control. In this experiment, Fe and Zn were supplied by sources of iron (II) sulfate heptahydrate (FeSO4.7H2O, 0.5%) and Zinc sulfate heptahydrate (ZnSO4.7H2O, 0.5%), respectively. The traits examined in this study included germination percentage, radicle length, plumule length, seedling weight vigor index and the content of photosynthetic pigments and carotenoid.
Results: The results of this experiment indicated that the plumule length was more sensitive to drought stress, as compared with the root length. With increased intensity of drought stress from 0 to – 0.9 MPa, the content of photosynthetic pigments in Stevia significantly decreased in all the priming treatments, so that the lowest amounts of chlorophyll a, b and carotenoid were observed at the potential of – 0.9 MPa. Priming with SA + Fe + Zn was found to be more effective than other treatments in improving the germination characteristics and the chlorophyll content of Stevia under normal and drought stress conditions. At the highest level of drought stress, germination percentage, radicle length, plumule length, seedling vigor index and total chlorophyll content increased by 55.7, 50.5, 74.3, 90.3 and 85.5%, compared with the control in the concurrent application of Fe, Zn, and SA.
Conclusion: In general, seed priming by micronutrient elements (Fe and Zn) and salicylic acid, and particularly their integrated application, could be recommended to increase the resistance of Stevia to drought stress in the germination phase.
 
 
Highlights:
  1. Drought stress at the germination stage has a significant effect on the seedling growth and the content of photosynthetic pigments in Stevia.
  2. Seed priming increases drought tolerance of Stevia at the germination stage.
  3. The integrated application of SA, Fe, and Zn is more effective than their separate application to alleviate the drought-induced damaging effects.

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 (3-2020)
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.

Evaluation of Seed Germination and Seedling Growth Characteristics of Sweet Pepper (Capsicum annuum) Under Salinity and Drought Treatment
Mohammad Hossein Aminifard, Hassan Bayat,
Volume 6, Issue 2 (3-2020)
Abstract


Extended abstract
Introduction: Pepper (Capsicum annum L.), which belongs to the solanaceae family, is one of the most important vegetable and garden products. Due to its nutritional value, its use tends to rise all over the world. Germination and seed emergence are strongly influenced by environmental stresses such as salinity and drought. Drought stress affects various aspects of plant growth. It reduces germination, delays vegetative growth and reduces dry matter in the plant. Salinity stress, as an environmental stress, is a limiting factor for the growth and development of crops and garden production.
Materials and Methods: The present study was conducted to evaluate the impact of drought and salinity stress on seed germination characteristics of sweet pepper (Capsicum annuum L.) in two separate experiments, using a completely randomized design with three replications in the Faculty of Agriculture, University of Birjand in 2016. PEG 6000 was used for drought stress and NaCl, for salinity stress. The treatments included drought and salinity stress levels (0, -2, -4, -6, -8, -10 and -12 bars). Seeds were disinfected with sodium hypochlorite (2%) solution for 1 minute, and were then washed with distilled water. The medium was petri dishes with a diameter of 9 cm.  25 seeds were placed on two layers of filter papers in each dish. 5 ml of distilled water or solution was added to each petri dish. The measured traits were germination percentage, germination rate, seed vigor index, radicle length, plumule length, ratio of radicle length to plumule length and dry weight of radical and plumule.
Results: The results indicated that salinity and drought stress had significant effects on seed germination characteristics of sweet pepper so that salinity stress with osmotic potential of -10 and -12 bar decreased the germination of sweet pepper and reached zero. Increasing salinity stress from zero to -12 bar decreased germination percentage, germination rate and seedling dry weight by 43.75, 41.67 and 93.46%, respectively. The results indicated that with increases in both salinity and drought stress, seed vigor index decreased significantly. The results showed that with increasing drought and salinity stress from 0 to -12 bar, seed vigor index decreased 96.58 and 100 percent, respectively.
Conclusions: The results of this study showed that the tolerance of sweet pepper to salinity stress was higher than its tolerance to drought stress at the germination stage, but for more accurate evaluation, it is necessary to conduct additional experiments in the field and in the greenhouse.
 
 
Highlights:
1- Investigation and comparison of germination and seedling growth of sweet peppers under salinity and drought stress.
2- Salinity and drought stress reduce germination indicators of Capsicum annuum.

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