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Hossein Nastari Nasrabadi, Mehdi Moradi, Mohammad Naser Modoodi,
Volume 5, Issue 2 (3-2019)
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:
- Effect of salinity on seed germination characteristics of melon.
- Effect of biofertilizer and salicylic acid on germination and seedling growth of melon under salt stress.
Farnaz Porali, Farshid Ghaderi-Far, Elias Soltani, Mohammad Hadi Palevani,
Volume 5, Issue 2 (3-2019)
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:
Hasan Teimori, Hamidreza Balouchi, Ali Moradi, Elias Soltani,
Volume 5, Issue 2 (3-2019)
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:
- Study of germination and biochemical properties of fenugreek seed aged under different level of osmotic potantials and temperatures.
- In areas with a lower osmotic potential it is better to cultivate Fenugreek seed at temperatures below 20 °C.
Maryam Mokhtari, Sina Fallah,
Volume 6, Issue 1 (9-2019)
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:
- Gibberellin and salicylic acid treatments make pumpkin seedling tolerant to low temperatures.
- Application of gibberellin and salicylic acid increases the activity of antioxidant enzymes.
- By using gibberellin and salicylic acid, the effect of possible chilling can be reduced at the beginning of the growing season.
Narjes Hojati Fahim, Mohamad Sedghi, Mehrdad Chaeichi, Rraouf Seyed Sharifi,
Volume 6, Issue 1 (9-2019)
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:
- Evaluation of germination indices for recent cultivars of rainfed wheat, released by rainfed Research Institute of Iran.
- Investigating and comparing fertilizers with various multifactorial compounds (fungi and bacteria) and with each other.
- 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)
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
Mahsa Nazer, Seyed Mohammadreza Ehteshami, Masoumeh Salehi, Ali Kafighasemi,
Volume 6, Issue 1 (9-2019)
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:
- To investigate the qualitative indices of Guar seed on the mother plant during seed filling period
- To determine the best harvest time and its adaptation with the highest quality of Guar seed
Saman Sheidaei, Aidin Hamidi, Hossein Sadeghi, Bita Oskouei, Leila Zare,
Volume 6, Issue 1 (9-2019)
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:
- Introduction of proper storage conditions and initial seed moisture in order to decrease fungal damage and soybean seed deterioration.
- Determination of different fungal damages during the storage of soybean seeds.
- 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.
Ashraf Alizadeh-Amraie, Abdollah Javanmard, Hamdollah Eskandari,
Volume 6, Issue 1 (9-2019)
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:
- Seed quality of mung bean during seed growth and development was evaluated.
- Effect of deficient irrigation induced by partial root zone irrigation on seed quality of mung bean was determined.
- The effect of planting pattern of mother plants on seed quality was investigated.
Mahnaz Tatari, Ebrahim Gholamalipour Alamdari, Zeinab Avarseji, Mehdi Zarei,
Volume 6, Issue 2 (3-2020)
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.
Marzie Soltani Alikooyi, Ali Abbasi Surki, Mohsen Mobini Dehkordi, Shahram Kiyani,
Volume 6, Issue 2 (3-2020)
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:
- Acinetrobacter calcoaceticus bacterium increased the percentage and rate of germination of alfalfa seeds under salt stress.
- Enterobacter aerogenes bacteria efficiently adjusted the negative effects of salinity on alfalfa seedlings length and dry weight.
Mohammad Ghayour, Majid Taherian, Sadegh Baghban, Saeed Khavari,
Volume 6, Issue 2 (3-2020)
Volume 6, Issue 2 (3-2020)
Abstract
Extended Abstract
Introduction: The effect of environmental factors on the developmental stages of a plant causes the planting date to vary from one region to another. Temperature is a very important factor in the maximum percentage germination and germination rate. Priming improves germination rate, brings about the uniformity of germination and reduces seed susceptibility to environmental factors. The purposes of this experiment were to study the effects of priming treatments at different temperatures on the germination characteristics of Hibiscus sabdariffa under laboratory conditions, to investigate priming treatments on different planting dates and to compare early planting dates on the farms.
Materials and Methods: The experimental study was carried out as a factorial experiment in a completely randomized design with four replications in the Laboratory of Seed Technology of Kashmar University Jihad. The first factor is five primings (Concentrations of ZnSO4 (10 mM), Humic acid (2.5 cc) and the combination of Humic acid and Zinc sulfate, Biological materials (Pota Barvar 2), no treatment (control) and the second factor is five levels of temperature: 10, 12, 14, 16 and 18 °C. Field studies were carried out in Agricultural and Natural Resources Research Center of Kashmar in three separate experiments in 2018. The research was carried out in a completely randomized block design with three replications on three planting dates (March 25th, April 15th, and May 4th, 2018). In each experiment, priming treatments were applied similarly to field experiments.
Results: The results of the current experimental study showed that temperature, priming and temperature interaction with priming had a significant effect on all the traits studied. The highest percentage and rate of germination were observed at 18 °C and priming with Pota Barvar 2. The results also showed that planting date had a significant effect on all the traits studied in the field experiment. Priming showed a significant difference only in stem fresh weight. The interaction effect of priming and planting date was not significant for the traits studied. The highest germination percentage was obtained on April 15’s planting date. By planting later than March 25 to 15 April, a decrease of 74% was observed in the rate of germination. Among priming treatments, the combination of Zinc Sulfate and Humic acid showed a significant superiority, compared with other treatments.
Conclusion: The findigns suggest that due to the high sensitivity of seed germination of sour tea at low temperatures, the planting date in each area should be carefully chosen so that it does not coincide with temperatures below 18 °C.
Highlights:
- Evaluation of the effect of seed priming treatment at different temperatures on germination characteristics of Roselle under laboratory conditions.
- A different priming treatment leads to increases in germination characteristics of Roselle.
Maryam Akbari, Mehdi Baradaran, Mohammadreza Amerian, Naser Farrokhi,
Volume 6, Issue 2 (3-2020)
Volume 6, Issue 2 (3-2020)
Abstract
Extended abstract
Introduction: A wide range of deteriorative conditions (especially moisture content and temperature) may affect seed quality during storage which may lead to seed aging. As the most important component of the phenylpropanoids pathway, trans-cinnamic acid, found abundantly in plants and its endogenous levels is influenced by stress conditions. The present study was conducted to investigate germination features, seed reserve mobilization, electrolyte leakage and malondialdehyde content in aged cowpea seeds affected by different concentrations of cinnamic acid.
Materials and Methods: The research has been performed in the laboratory of Faculty of Agriculture, Shahrood University of Technology, Iran. The experiment was designed as a factorial (two factors of the experiment included two levels of seed quality including non-aged and aged seeds and five levels of cinnamic acid concentrations including 0, 15, 30, 45 and 60 µM) based on a completely randomized design. Accelerated aging was applied as an efficient method to mimic storage conditions in the presence of accelerating factors. Cowpea (Vigna unguiculata) seeds (Bastam local variety) were incubated in a relative humidity of 95% and a temperature of 43 °C for 72 h to accelerate aging. Both seed lots were treated with 5 different concentrations of cinnamic acid for 6 h followed by standard germination and vigor tests. Data of germination and vigor tests were processed using the GERMINATOR software. Heterotrophic growth, seed reserves mobilization, electrical conductivity and membrane lipid peroxidation were assessed using the available methods.
Results: In this study, cowpea seeds responded to cinnamic acid differently based on their primary quality. In deteriorated seeds, concentrations of 45 µM and 60 µM could successfully enhance seed germination percentage, as compared with the aged seeds (i.e., control). A concentration of 45 µM also improved the vigor of deteriorated seeds. Seed pretreatment of 15, 30 and 45 µM enhanced seed reserves utilization in non-aged seeds. Aging negatively affected area under curve, germination uniformity and seedling dry weight of the deteriorated seeds. Application of 30 µM cinnamic acid improved germination uniformity. The area under the curve was positively affected by 15µM and 30µM. Concentrations of 45 µM and 60 µM enhanced seedling dry weight. Applying 45 µM cinnamic acid decreased electrolyte leakage by 38% and improved efficiency of seed reserves mobilization. Moreover, seed malondialdehyde content, as an indication of membrane lipid peroxidation, showed a sharp decline by applying increased concentrations of cinnamic acid.
Conclusions: Based on our results, cowpea seeds respond to cinnamic acid differently based on their primary quality. These results imply that seed pretreatment with 45 µM cinnamic acid may successfully invigorate aged cowpea seeds. We also conclude that cinnamic acid application cannot improve physiological traits and can be regarded as a potent antioxidant in the invigoration of the aged seeds.
Highlights:
- This is the first study focusing on the role of cinnamic acid in alleviating deterioration in aged seeds.
- Cinnamic acid has been introduced as a robust antioxidant, which is effective in reducing the deleterious effects of seed deterioration.
Akram Rostamipoor, Ali Mordai, Hamidreza Eisvand,
Volume 6, Issue 2 (3-2020)
Volume 6, Issue 2 (3-2020)
Abstract
Extended Abstract
Introduction: Seed dormancy, as a technique to avoid environmental stress, is important in preserving plant species and could be of various types including physiological, physical, morphological and morph-physiological dormancy. Seed testa hardness is one of the main causes of dormancy in leguminous family plants. A common method for breaking seed dormancy in leguminous plants is the use of scarification treatments. Given that oxygen deficiency is a factor that induces dormancy, scarification treatments through acceleration of gas exchanges, especially oxygen and carbon dioxide, can reduce seed dormancy and finally increase germination percentages. In addition, priming with gibberellic acid can help dormancy breaking in plant species that have physiological dormancy, finally leading to germination. Therefore, the present study investigated seed dormancy and germination to find the most appropriate treatment for the elimination of seed dormancy in three ecotypes of Astragalus cyclophyllus.
Materials and Methods: A factorial experiment based on a completely randomized design with three replications was carried out at Agriculture Laboratory of Lorestan University in 2013. The first factor was three ecotypes of Astragalus Semirom, Damavand and Zanjan, and the second factor was seed dormancy breaking treatments. The applied treatments were: control, (mechanical scarification plus chilling time with 10, 20 and 30 days prechilling at 4°C, mechanical scarification + gibberellic acid at concentrations of 400 and 500 ppm for 48 hours, scarification with sulfuric acid 96% for 2 and 4 min, mechanical scarification and 2% potassium nitrate for 72 h, mechanical scarification and gibberellic acid 400 ppm for 48 h and 20 days prechilling. The measured indices included germination percentage, mean germination time, seedling length, seedling fresh weight, seedling dry weight and alpha-amylase activity.
Results: The results showed that the interactions between seed dormancy breaking treatments and ecotype were significant for all the traits. Based on the results of mean comparison, Damavand ecotype exhibited better performance in terms of most of the traits studied, as compared with Semirom and Zanjan ecotypes. Compared with the treatments applied, mechanical scarification plus gibberellic acid 400 ppm was more effective in germination parameters and seedling vigor index. Mechanical scarification and gibberellic acid 400 ppm for 48 h along with 20 days prechilling increased total germination percentage by an average of 67.68% in Semirom ecotype and was more effective in increasing the activity of α-amylase enzyme.
Conclusion: It seems that seed dormancy of Astragalus cyclophyllus is not of physiological type and increased germination can be due to mechanical scarification in physical dormancy breaking and priming effect of prechilling and gibberellic acid.
Highlights:
- The effect of different dormancy breaking treatments on seed germination was investigated.
- Alpha-amylase activity of Astragalus Seed increased under dormancy breaking treatments.
Mohsen Malek, Farshid Ghaderi-Far, Benjamin Torabi, Hamid Reza Sadeghipour,
Volume 6, Issue 2 (3-2020)
Volume 6, Issue 2 (3-2020)
Abstract
Extended Abstract
Introduction: Priming is one of the most commonly used seed enhancement techniques. Events such as increased synthesis of nucleic acids, activation of repair processes, increased respiratory activity, and improved antioxidant capacity during priming lead to advanced metabolism in seeds. The most important effects of priming include increased percentage, speed and uniformity of germination and emergence. However, the longevity of primed seeds in storage is the major concern for researchers as it restricts widespread use of this technique. Some researchers believe that priming reduces the storage capacity of seeds, while others have reported increased seed shelf life after using priming treatments. Therefore, this study sought to investigate the effects of priming on the storage capacity of the seeds of canola cultivars under different storage conditions.
Material and Methods: In this study, the effects of priming on the shelf life of seeds of three canola cultivars including Dk-xpower, Traper and Hayola50 were investigated. For this purpose, the seeds were first treated with hydropriming and osmopriming methods. Then primed and control seeds with 6, 9, 12 and 15% moisture content were stored for 8 months at 15, 25, 35 and 45 °C. Sampling from different seed treatments was carried out at intervals of 1 to 30 days to assess germination. Finally, by fitting a three-parameter logistic model to cumulative germination data versus the day after storage, the time to germination loss to 50% was calculated and used to compare seed storage behavior between the treatments.
Results: The results showed that the storage behavior of canola seed varies greatly depending on the cultivar, and each cultivar showed a distinct behavior. Priming effects on the shelf life of seeds were different depending on the storage conditions, cultivars and also the priming methods. Comparison of the effects of priming on the seeds’ shelf life under different storage conditions showed that priming treatments were more efficient under higher seed moisture content and storage temperatures than those with lower seed moisture content and storage temperatures. In addition, priming treatments in Dk-xpower cultivar often increased the seeds’ shelf life. However, in the Traper and Hayola 50 cultivars, hydropriming often improved the seeds’ shelf life, and in contrast to osmopriming, it led to a decrease in the shelf life of the seeds.
Conclusion: Based on the results of this study, it was shown that priming effects on canola seed viability can be a function of various factors such as cultivar, storage conditions, and also the type of priming treatment. Moreover, in this study, hydropriming often increased seed longevity whereas osmopriming often increased the deterioration rate and reduced seed longevity.
Highlights:
- Seed storage behavior of canola cultivars was compared under natural storage conditions.
- Priming effects on seed longevity of canola cultivars was investigated under different storage conditions.
Mahboubeh Hajiabbasi, Reza Tavakkol Afshari, Alireza Abbasi, Reza Kamaei,
Volume 6, Issue 2 (3-2020)
Volume 6, Issue 2 (3-2020)
Abstract
Extended Abstract
Introduction: Soybean (Glycine max (L.) Merrill) is the primary source of vegetable oil. Even in desirable conditions, soybean seeds lose their viability in long term storage. Many factors contribute to seed deterioration, including genetic factors, mechanical damage, relative humidity, storage temperature, seed moisture content, existence of microflora, and seed maturity, which reduce seed quality and make seeds unfit for cultivation purposes.
Materials and Methods: In order to investigate the effects of seed deterioration on seed germination and also the effects of salicylic acid and ethylene on the improvement of deteriorated seeds of G. max., accelerated aging test for 0, 6 and 10 days and natural aging test for 6 months were conducted. After aging conditions, seeds were imbibed with 50 µM salicylic acid and 10 µM ACC (precursor of ethylene) for 6 hours at 25 °C. In addition, after natural and accelerated aging tests, a bunch of seeds was used without any hormonal treatment (i.e., dry seeds) as control seeds. The seeds’ germination percentage, total sugar, fructose, and glucose were investigated. Moreover, the gene expression of GAI1 and LOX1 was measured on dry seeds and under imbibition of water, salicylic acid and ACC at 6, 12 hours using Q-RT-PCR method.
Results: The germination results showed that increasing number of aging days led to a decrease in germination. Total sugar content in seeds aged for 6 days did not have a significant difference, as compared with non-aged seeds. However, total sugar content in seeds aged for 10 days was significantly higher than non-aged seeds. Increasing accelerated aging levels from 0 days to 10 days led to increases in glucose and fructose contents in dry seeds. In addition, genes exhibited different expressions in different days and hours. Increasing aging from 0 days to 10 days led to increases in GAI1 gene expression. Moreover, LOX2 expression increased in accelerated aging from 0 to 6 days. LOX2 gene expression in naturally dried aged seeds also increased and was higher than that in non-aged seeds. SA and ACC had different effects on measured values.
Conclusion: In general, it can be concluded that the deterioration of seed quality and vigor result from numerous degradation processes and disruption in seeds’ physiological activity. This study showed that aging is associated with an increase in total sugar, glucose and fructose levels. In addition, the expression of the genes involved in the germination is also affected. Increases in LOX2 gene expression were observed in both accelerated aging and natural aging pathways. GAI1 gene expression increased in accelerated aging. However, in normal aging, it decreased.
Highlights:
- Identifying the role of LOX2 and GAL1 genes in soybean seed deterioration.
- Investigating seeds’ physiological responses under natural and laboratory aging conditions.
Leila Karami, Mohammad Hedayat, Somayeh Farahbakhsh,
Volume 7, Issue 1 (9-2020)
Volume 7, Issue 1 (9-2020)
Abstract
Extended abstract
Introduction: Seed germination is a complex and dynamic stage of plant growth, and seed priming is a technique by which the seeds obtain germination potential physiologically and biochemically before being placed on growth media and facing the ecological conditions of the environment. Seed priming increases yield and antioxidant enzymes in plants by increasing germination and seed vigor and as a result, increases percentage of germination. Several studies have investigated the effect of seed priming with organic materials including salicylic acid on improving seed germination in various plant species. Research results have shown that salicylic acid can be used as a growth regulator to increase the germination of plants. Tomato, with scientific name of Lycopersicon esculentum (Mill), belongs to the Solanaceae family and is widely adapted to different climatic and soil conditions. The aim of this study was to evaluate the effect of different concentrations of Salicylic acid on seed germination and some factors of morphophysiologic and biochemical traits of tomato seedlings.
Materials and methods: This research was conducted as factorial in a completely randomized design, including priming treatment in 3 time frames (12, 18 and 24 hours) with three replications. Priming treatments consisted of salicylic acid (2, 2.5 and 3 mg/l) and distilled water. The measured traits were germination parameters including percentage, time, rate, and uniformity of germination and morphological traits including transplant height, crown diameter, root length, leaf number, and leaf area, shoot and root fresh and dry weight and biochemical traits including chlorophyll, peroxidase enzyme, proline, total nitrogen, potassium, calcium, phosphorus, and sodium.
Results: The favorable effect of salicylic acid was obtained at the concentration of 3 mg/l on mean germination time compared to the distilled water. The positive effect of salicylic acid was observed on transplant height and leaf area (at the concentration of 3 mg/l at 18 and 24 hours’ time frame), shoot and root fresh and dry weight (at 24 hours) compared to the control. Immersion in distilled water for a period of 12 and 24 hours resulted in the highest root length, while salicylic acid treatment reduced root length significantly. The highest transplant height (14.3 cm), leaf number (34), chlorophyll index (59), peroxidase enzyme (10873 unit/g.min-1), total nitrogen (2.89%), potassium (9.81%), and proline content (14.80 µM/g fresh weight) were observed in 24 hours treatment with concentration of 3 mg / l salicylic acid.
Conclusion: According to the results of this study, salicylic acid at certain concentration improves seeds germination of tomato plants through the regulation of physiologic and biochemical processes. It seems that salicylic acid led to increase in plant growth and improvement of seed germination and morphophysiological parameters of the tomato via affecting cell growth and division. Seed priming with salicylic acid at the concentration of 3 mg/l and in longer time frames had positive effect on most traits, whereas the results for each trait were different in relation to priming time.
Highlights:
1-Priming of tomato seed in distilled water for 18 hours reduces the time of seed germination.2-Salicylic acid can be used as an appropriate pretreatment for producing seedlings with better quantitative and qualitative characteristics by affecting the morpho-physiologic and biochemical properties of tomato seedlings.
Roya Behboud, Ali Moradi, Hooshang Farajee,
Volume 7, Issue 1 (9-2020)
Volume 7, Issue 1 (9-2020)
Abstract
Extended Abstract
Introduction: Sweet corn (Zea mays var. saccharata) is a corn variety that is distinguished from other varieties due to the presence of genes that affect starch production in the endosperm. Given that the most of plants including sweet corn face with problems such as non- uniform germination and poor seed emergence in the early stages of germination. Thus, the use of organic stimulants is one of the ways to reduce the harmful effects of non-biological stresses, increase seed germination, uniform appearance and increase their yield and quality. The present study was carried out to investigate the effect of different concentrations of chitosan on seed germination and some biochemical traits of sweet corn under osmotic potential conditions.
Materials and Methods: To investigate the effect of chitosan and osmotic stress on germination and biochemical parameters of sweet corn, a factorial experiment was conducted in a completely randomized design with four replications at the Seed Technology Laboratory, Faculty of Agriculture, Yasouj University in 2017. The first factor was osmotic stress at 0, -3, -6, and -9 bar osmotic potentials and the second factor was pre-treatment at five levels of chitosan zero, 0.25%, 0.5%, 0.75% and 1% and one level of distilled water. The seeds were immersed in the desired solutions of chitosan for 3 hours at 25 °C and under dark conditions, and then the pre-treated seeds were germinated under standard germination condition. In each petri dish, 25 seeds were placed on a filter paper and osmotic potential was applied using polyethylene glycol 6000. Seed germination was carried out in the germinator at 25 ± 1 ° C for 7 days under dark conditions. The germination traits and biochemical traits were measured according to standard methods.
Results: Osmotic stress reduced germination percentage and germination rate, seedling vigour length index, germination uniformity coefficient, allometric coefficient, and soluble protein content and also increased the mean germination time, proline, soluble sugar content and hydrogen peroxide. Pre-treatment of seeds with a concentration of 0.5% chitosan increased protein, proline, and soluble sugars content at all osmotic stress levels. At the osmotic stress levels, the highest and lowest levels of hydrogen peroxide respectively were observed in 0.5% chitosan treatment and distilled water treatment. The results showed that pre-treatment with 0.5% chitosan increased germination percentage and rate and seedling vigour length index, and also reduced the mean germination time and malondialdehyde. Pre-treatment of seed with zero and 1% chitosan led to reduction in some of the germination and biochemical traits in comparison with 0.25, 0.5, and 0.75% chitosan.
Conclusions: The results showed that seed treatment with 0.5% chitosan could reduce the harmful effects of osmotic potential on some germination and biochemical traits in sweet corn seedlings and improve seedling growth.
Highlights:
1-Chitosan increases the germination percentage and germination rate.
2-Chitosan increases soluble sugars, proline, and soluble protein.
3-Chitosan reduces the amount of malondialdehyde and hydrogen peroxide.
Hadi Pirasteh-Anosheh,
Volume 7, Issue 1 (9-2020)
Volume 7, Issue 1 (9-2020)
Abstract
Extended abstract
Introduction: Camelthorn (Alhagi maurorum) has a high tolerance to salt and water stresses, and its forage quality is greater than cereal straw and is equal to alfalfa. Seeds of camelthorn do not germinate easily due to the hard seed coat. Therefore, camelthorn cultivation as an agricultural crop needs more research, especially on breaking seed dormancy and increasing germination. Despite numerous studies about camelthorn as a weed, there are few studies on evaluating agronomic factors of camelthorn as a field crop. Hence, in this study, some aspects of germination and salinity tolerance of camelthorn were examined.
Materials and Methods: In this research, different aspects of camelthorn germination were examined at the National Salinity Research Center in 2018. In the first experiment, different pretreatments including control, sandpaper, hydro-priming, hot water, and sulphuric acid were assessed. With the selection of sulphuric acid as the best treatment, varying durations (0, 5, 10, 15, 20, and 25 min) and concentrations (98% and 75%) of sulphuric acid priming were compared in the second and third experiments. In the fourth experiment, the seeds collected in 2018 were compared with the seeds collected in 2017 and 2016. The effect of different salt stress levels (0, 6, 12, 18, 24, 30, and 36 dS m-1) was evaluated on camelthorn germination and early growth in the fifth experiment. In the sixth experiment, lighting regimes including continuous dark, continuous light, and an alternative period of dark- light were examined and in the seventh experiment sibling factors (together and individual seeds) were evaluated. Seed germination and seedling length were calculated and salinity tolerance threshold levels and 50% reduction threshold were estimated.
Results: The results of the first experiment showed that the highest germination percentage was obtained in sulphuric acid priming (56.6%), which was six folds greater than the control. In the second experiment, it was shown that the highest germination percentage (81.1%) and seedling growth (5.7 cm) was observed in sulphuric acid priming 98% for 25 min. Important note was that these results were related to domestically produced sulphuric acid, and the highest germination and seedling growth were observed in 75% concentration for the imported sulphuric acid. In the fourth experiment, it was found that at least 3 years of seed longevity had no significant effect on seed germination. Considerable losses in germination and growth were observed from 30 dS m-1 salinity level; however, germination did not completely stop even at 36 dS m-1 salinity. In the sixth and the seventh experiments, it was found that there were no significant differences between seeds germination in the continuous dark, continuous light, and an alternative period of dark- light as well as between individual and together seeds. So, camelthorn seed is not photoblastic and had no negative sibling factor.
Conclusions: Generally, it was concluded that the best method for improving germination is priming with sulphuric acid 98% (internal) or 75% (imported) for 25 min. According to achievement of high germination in sulphuric acid pre-treatments (chemical scarification), it seems that seed dormancy in camelthorn is presumably physical. Furthermore, although the salinity tolerance threshold of this plant is estimated 14.2 dS m-1, it can germinate minimally even in very higher salinity. Light salt stress not only decreases the germination of this plant but also is necessary for growth promoting. Based on the high salinity tolerance of camelthorn in the germination stage, its cultivation in haloculture systems is recommended for more investigation.
Highlights:
1- Sulphuric acid 98% priming for 25 min led to breaking seed dormancy and acceptable camelthorn germination.
2- In moderate salinity, germination was not significantly changed and seedling growth was promoted compared with the non-stress conditions.
3- Salinity tolerance threshold level of camelthorn was estimated 14.2 dS m-1.
Esmaeil Gholnezhad, Naser Samsami, Abbas Abhari,
Volume 7, Issue 1 (9-2020)
Volume 7, Issue 1 (9-2020)
Abstract
Extended abstract
Introduction: Soybean is a plant that has a moderate tolerance to drought stress. Drought stress is one of the most important abiotic stresses affecting soybean production by about 40%. In addition, drought stress reduces seed vigor as a result of stress conditions. Positive effects of mycorrhizal fungi on the increment of dry matter and plant biomass, especially in low-irrigated conditions and in dry areas have been proven. The reason for the increase in crop yield in mycorrhizal inoculated plants is their water balance in water deficit stress conditions and as a result, absorption of water and mineral elements. Rhizobium bacteria, carbohydrates, and other foods are catched from the phloem vessels and the received energy is used to convert nitrogen to ammonium ion and eventually amino acids. Japonicum rhizobium bacterium is not naturally found in soils of Iran and the bacteria should be added to the soil along with seeds.
Materials and Methods: This experiment was carried out to determine the germination characteristics, seed vigor and its related traits in soybean Kosar cultivar grown under drought stress conditions and inoculation with mycorrhiza and bacteria with three replications during 2018. In the field experiment, drought stress included optimal irrigation (irrigation after 70 mm evaporation), moderate stress (irrigation after 110 mm evaporation) and severe drought stress (irrigation after 150 mm evaporation from class A evaporation pan), mycorrhizal fungus in three levels, mycorrhiza-free, and inoculation with glomus mosseae, Glomus intraradices and Rhizobium bacterium in two levels, including no inoculation and inoculation with Rhizobium japonicum.
Results: The mean comparison showed that the seeds obtained under normal irrigation, inoculation with mycorrhiza and bacteria had the highest dry weight of radicle, plumule and seedling, percentage and germination rate. The lowest electrical conductivity of the seeds and the mean time of germination were obtained under these condition. Severe and moderate drought stress reduced stress tolerance index, root tolerance index and stem tolerance index, seedling vigor index and seed vigor index compared to optimum irrigation about 42-23, 38-18, 30-18, 50-26 and 41-21) percent, respectively. Inoculation with Glomus mosseae and Glomus intraradices increased the seed vigor index, radicle lentgh, plumule lentgh and seedling length compared to non-inoculation with mycorhizal fungi by 48-42, 27-26, 41-37 and 35-33 percent, respectively. Inoculation with Rhizobium japonicum increased radicle lentgh, plumule lentgh and seedling lentgh compared to non-inoculation with bacterium by 21%, 16% and 18%, respectively. The highest water percentage in seedling tissue was obtained under optimum irrigation conditions, inoculation with mycorrhizal fungi and inoculation with rhizobium bacteria.
Conclusion: According to the results of this study, in all three different irrigation conditions to improve germination and increase seed vigor, the use of mycorrhiza fungi is effective especially glomus mosseae and inoculation with Rhizobium bacteria.
Highlights:
- Germination characteristics, germination rate and duration of soybean Kosar cultivar on seeds obtained under different irrigation conditions were investigated.
- The effect of mycorrhiza and bacteria on seed vigor and related traits were evaluated under different levels of drought stress.
- The damage done to the seed membranes due to the interaction of irrigation and inoculation with mycorrhiza and bacterium was investigated.
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Seed Science and Technology, Seed Physiology, Seed Ecology, Modeling, Seed Health, Germination Characteristics, Seed Dormancy, Seed Ageing, Seed Storage, Seed PrimingVote
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