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Showing 7 results for Stratification
The Study of Seed Germination and Dormancy of Chenopodium album, Convolvulus arvensis and Setaria viridis in Pistachio Orchards of Rafsanjan, Iran
Mostafa Alinaghizadeh, Mohammad Khajeh-Hosseini, Seyed Ahmad Hosseini, Mohammad Hasan Rashed Mohasel,
Volume 3, Issue 2 (2-2017)
Abstract

In order to study the seed germination behavior and dormancy breaking methods of three weed species (i.e., Chenopodium album, Convolvulus arvensis and Setariaviridis) of pistachio orchards in Rafsanjan, Iran, three separate factorial experiments (with 2 factors) were conducted based on a completely randomized design with four replications, at the Faculty of Agriculture, Vali-E-Asr University of Rafsanjan, Iran, in 2014. Weed seeds were collected from five different regions of Rafsanjan, such as Markazi, Anar, Koshkoiyeh, Kabotarkhan and Nogh. Dormancy breaking treatments for Chenopodium album involved distilled water (control), KNO3 (at 500 and 1000 ppm), chemical scarification by sulfuric acid (for 5 and 10 min), and cold stratification (for 1, 3 and 5 weeks). Treatments for Convolvulus arvensis involved distilled water (control), scarification by sandpaper, chemical scarification by sulfuric acid (20 and 30 min), and boiling water (for 15 and 30 min). Treatments for Setaria viridis involved distilled water (control), gibberellic acid (250, 500 and 1000 ppm), KNO3 (500 and 1000 ppm), and cold stratification (for 1, 3 and 5 weeks). The results showed that seed germination percentage (SGP) and mean germination time (MGT) of three weed species were significantly different among weed populations and dormancy breaking methods. For Chenopodium album, cold stratification of 5 weeks resulted in highest SGP (97%) in Nogh population. For Convolvulus arvensis and Setaria viridis, the highest SGP was obtained after scarification by sandpaper (98% in Kabotarkhan population) and using 1000 ppm gibberellic acid (60% in Kabotarkhan population), respectively. In addition, increasing the weight of 1000 seeds in the three weed species in question increased SGP.
 
 


Facilitating Seed Germination of Eight Species of Hawthorn (Crataegus spp.) Native of Iran, Using Chemical Scarification and Cold Stratification
Masume Hematifar, Ali Tehranifar, Hasan Akbari Bishe, Bahram Abedi,
Volume 4, Issue 2 (3-2018)
Abstract

Given the medicinal and ornamental properties of Hawthorn (Crataegus spp.), and given that there are some problems in its propagation, which is due to the hard cover of the seeds and immature embryo, working out techniques that can facilitate the process of seeds’ germination is of great import. Thus, the present study sought to identify the best method for the purpose of breaking the seed dormancy of 8 species of native hawthorn of Iran. The study was carried out as factorial with a completely randomized design and had three replications. The first, second and third factors were, respectively species of Hawthorn in eight levels, sulfuric acid in three levels (half and an hour versus non-treated (control) and chilling treatment in three levels (90, 105 and 120 days, respectively). The results showed that the highest percentage of germination (32%) and germination rate (9.1 day-1) were obtained under the interaction of sulfuric acid treatment for one hour, followed by a 120-day chilling period in C.turkestanica, which had a significant difference with other treatments. It is concluded that hawthorn seeds have deep endocarp and physiological dormancy. The interaction of Sulfuric acid treatment and moist chilling play an important role in increasing the percentage and speed of germination of Hawthorn seeds.

Highlights:

  1.  Achieving the best way to break the dormancy of Hawthorn seeds in different species and genotypes.
  2. Shortening the seeds’ germination time.

Effects of Seed Pretreatments on Seed Germination Characteristics of Sugar Beet (Beta vulgaris) under Drought Stress Conditions
Jamal Kiani, Ali Abbasi Surki, Abdulrazagh Danesh Shahraki,
Volume 5, Issue 1 (9-2018)
Abstract
Extended abstract
Introduction: Drought stress is one of the major problems in sugar beet production in Iran, and is the most important limiting factor for germination and establishment of sugar beet in the early stages of growth. Seed priming with chemical, nutrient elements or pre-chilling techniques are the most effective methods to improve germination percentage and speed, leading to uniform and tolerant seedlings in adverse environmental conditions.
Material and Methods:  In order to assess the effect of cold stratification and HCl treatments on the germination of sugar beet seed, cv. Ekbatan, under drought stress conditions, a RCBD factorial experiment with three replications was conducted in Seed Science and Technology Lab of Shahrekord University.  The first factor was stratification in two levels; the second factor was  seven levels of pretreatments including 2, 4 and 6 hours’ soaking in water and 0.03 HCL accompanied with control, and the third factor was four drought levels (control, -2, -4, -6 bar).
Result: Compared with the control, seed germination percentage and germination rate increased by at least 5-fold, relative germination by 50% and root and shoot length by 10%, due to stratification and duration of exposure to HCl treatments. With no stratification, germination traits increased with increases in exposure time in acid, and the highest values were obtained for the seeds exposed to HCl 0.03 normal for 6 hours. Although under optimal conditions, the effect of HCl was compensated for by stratification, in drought conditions, the highest values ​​were observed in stratified seeds and those placed in acid.
Conclusions: Since successful establishment of sugar beet seedlings at drought stress conditions is critical to achieving optimum density and yield, application of stratification treatments for one week and seed exposure to HCl increased the seed performance under stress conditions. This trend continued to increase with drought stress intensity, and placement of seeds in acid doubled seed germination in -2 bar drought conditions, which continued by 4 times in -6 bar, compared with stratified control seeds. Compared to separate application of the treatments, application of stratification and HCl treatments had synergistic effects on sugar beet seed performance, especially under drought stress conditions.
 
 
Highlights:
  1. Cold stratification and hydrochloric acid treatments increase the efficiency of sugar beet seeds under drought stress conditions.
  2. Cold stratification and Hydrochloric acid treatment have a synergistic effect on sugar beet seeds.


Germination Characteristics and Seed Activity of Enzymes of Different Landraces of Indian Cheese Maker (Withania coagulans) in Response to Sodium Hypochlorite and Pre-chilling
Majid Ghanbari, Seyed Ali Mohammad Modarres-Sanavy, Ali Mokhtassi-Bidgoli,
Volume 5, Issue 1 (9-2018)
Abstract
Extended abstract
Introduction: Indian Cheese Maker, an herbage plant, belongs to potatoes family and grows in areas such as Pakistan, Afghanistan, India and Iran. Given its medicinal properties, Indian Cheese Maker plays an important role in traditional Iranian medicine. Lack of dormancy is one of the most desirable agronomic characteristics of its seeds, which is necessary to achieve the highest amount of germination, emergence and plant establishment. Seed germination capacity of medicinal herbs is typically low, which is due to the presence of seed dormancy in these plants.
Material and Methods: This study was conducted to evaluate the effect of disinfection and pre-chilling on germination and enzymatic properties of different Indian cheese maker landraces. The experiment was conducted as a factorial based on a completely randomized design with three replications during 2015-16 at the Laboratory of the Department of Agronomy, Tarbiat Modares University. Two treatments consisting of seeds disinfected at two levels (no application and 30 min with hypochlorite solution 5%), two pre-chilling treatments (no application and 1 week pre-chilling) and four Indian cheese maker landraces (Fanuj, Khash, Saravan and Sarbaz) were the experimental factors. For the purpose of suitable pre-chilling to activate the germination enzymes, the seeds were placed in a coated container, on an aluminum foil with holes in it, without direct contact and close to distilled water at 4 °C. 25 seeds were placed in each sterile petri dish with Watten filter paper 42. Five ml of distilled water was added to each petri. After applying the treatments, the petri dishes were covered with parafilm and were placed in a germinator at 25 °C in the light for 14 days.
Results: The results showed that in the Fanuj, Khash and Saravan landraces, the highest values of final germination percentage, germination rate, mean daily germination and mean time germination were obtained during disinfection of 30 minutes and pre-chilling of one week. However, the Sarbaz landrace showed a reverse trend and indicated the highest values of these traits in non-application of seed disinfection and pre-chilling. In terms of the activity of germination enzymes, the highest values of α and β amylase (0.74 and 0.59 μmol/ml/min) were obtained in the Fanuj landrace with 30-minute disinfection with sodium hypochlorite and one-week pre-chilling.
Conclusion: According to the results, the Fenuj, Khash and Saravan landraces of Indian Cheese Maker showed positive reaction to disinfection with sodium hypochlorite for 30 minutes and pre-cooling for one week. The same treatments increased the properties and activity of germination enzymes. The Sarbaz landrace did not react positively to the treatments applied and reacted negatively in terms of the properties and activity of germination enzymes. The reason for this behavior in the Sarbaz landrace could be attributed to lower annual rainfall, as well as higher temperature, which causes the hardening of the seed’s cover and the increase in the values of germination inhibiting factors, creating seed dormancy, which allows it to survive hot and dry periods. Generally speaking, the use of sodium hypochlorite and pre-chilling can be recommended to break seed dormancy of most Indian Cheese Maker landraces.
 
 
Highlights:
  1. Investigating the effect of mucilage inside the capsule on the inhibition of Indian cheese maker’s germination
  2. Assessing the activation pattern of germination enzymes to break dormancy of Indian cheese maker’s seeds
  3. Investigating the reaction of different Indian cheese maker landraces to dormancy-breaking protocols applied

Effect of Stratification and Its Combination with Gibberellic Acid on Seed Dormancy Breaking of Echinophora platyloba
Ali Abbasi Sourki, Zahra Hosseni, Sina Fallah,
Volume 5, Issue 2 (3-2019)
Abstract



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

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

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
Effective Methods for Improving Seed Germination of Medicago scutellata Affected by Salinity and Drought Stresses
Saeed Sharafi,
Volume 7, Issue 1 (9-2020)
Abstract


Extended Abstract
Introduction: Germination and seedling establishment are the primary stages of crop growth that are highly sensitive to salinity and drought stresses. On the other hand, seed hardness affects the quality of plant germination. Therefore, the aim of this study was to analyze the effect of seed pre-treatment on germination characteristics of Medicago scutellata var Rabinson.
Material and methods: In the present study, the effects of pre-treatment methods of scarification (sand paper, knife and sand), stratification (0, -5, -10, and -15 °C), ultrasonic waves (3, 6, 9, 12, and 15 min), and magnetic field (two intensities of 125 and 250 mT in 4 times exposure by 6, 12, 18, and 24 h) on seed germination of annual medic germination affected by salinity and drought stresses (0, -3, -6, -9, and -12 bar) were investigated with three replications. Twenty seeds per Petri dish were used for each treatment. Seedlings were incubated in the dark at 20/18±0.3°C in a growth chamber. After ten days, the dry weight of the seedling was obtained after oven drying at 70°C. Root length, shoot length, seed germination percentage, seedling growth rate (SLGR), the weight of mobilized seed reserve (WMSR), seed reserve depletion (SRDP), and seed reserve utilization efficiency (SRUE) were measured.
Results: Based on the preliminary results using Taguchi method, the -15 °C stratification treatments under salinity and drought, 6 and 9 min of exposure to ultrasonic waves under salinity and drought, and magnetic field intensity of 250 mT for 6 and 9 h were chosen for the experiment of salinity and drought, respectively. In salinity experiment, the maximum root length (23.47 mm), shoot length (15.76 mm), weight of mobilized seed reserve (0.119 mg per seed), and seed reserve depletion percentage (58.9 %) was in scarification treatment; the maximum seed germination (47.2 %) was observed in control treatment; the maximum seedling dry weight (0.195 mg) was identified in magnetic field treatment; and the maximum seed reserves utilization efficiency (0.665 mg.mg.seed-1) was obtained in ultrasonic waves treatments. In drought experiment, the maximum root length (22.84 mm), shoot length (8.09 mm), seed germination (49.93 %), the weight of mobilized seed reserve (0.096 mg per seed), and seed reserve depletion percentage (43.1 %) was measured in ultrasonic treatment; the maximum seedling dry weight (0.09 mg) was found in magnetic field treatment; and the maximum SRUE (0.516 mg.mg.seed-1) was observed in control treatment.
Conclusions: According to the results, there is a direct relationship between the decline in seedling dry weight and the decline in the weight of mobilized seed reserve. However, the scarification and ultrasonic waves' treatments had significant effects on seedlings resistance to salinity and drought, respectively. Furthermore, the use of ultrasonic waves and scarification produced higher germination percentage and more vigorous seedlings under drought and saline conditions. In terms of germination and seedling growth, the differences among the treatments increased by the increase in stress intensity. This advantage led to greater seed reserve utilization. Moreover, pre-treatment methods resulted in longer cotyledon length and improvement in vigorous seedlings. Future studies should focus on the study of enzymes activity and/or hormones affecting seed reserve utilization rate in response to drought and salinity stress.

 
Highlights:
1- The most sensitive growth stage of annual medic (seedling production stage) to salinity and drought stress was evaluated.
2- Various pre-treatments to improve the germination of annual medic to enter crop rotation in arid and semi-arid regions due to self-seeding and short growing period were investigated.

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