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Showing 13 results for Vigor Index
Effect of Seed Rate and Efficiency of PGPR on Quality of Alfalfa (Medicago sativa) Seed, Using Standard Germination and Accelerated Aging Tests
Hassan Habibi, Mehdi Agihghi Shahverdi, Zahra Nasiri, Mohammadreza Chaichi, Mohammad Hossein Fotokian,
Volume 1, Issue 2 (1-2015)
Abstract

The effect of seed rate of alfalfa (Medicago sativa L.) and efficiency of plant growth promoting bacteria (PGPR) that facilitates phosphorus uptake with different doses of phosphate fertilizer was evaluated on seed quality. For this purpose, the germination and seed vigor tests before and after accelerated aging were performed in a split split plot experiment based on randomized complete block design with three replications in 2010 in the field of education and research in the College of Agriculture and Natural Resources, Tehran University, Karaj. Phosphorus factor at 4 levels (0, 30, 60 and 90 kg Phosphorus.ha-1) in main plots, PGPR (Pseudomonas) in three levels (no bacteria, bacterial strains, No. 9 and bacterial strains No. 41) in subplots and rate of seed factors on three levels (2, 6, and 10 kg of seed per hectare) were the sub-subplots. The results showed the highest rate of germination and seed vigor obtained by use of 6 kg seeds per hectare, PGPR No.41 strains with 30 kg Phosphorus per hectare and after accelerated aging. The highest rate of germination and seed vigor at 10 kg of seed per hectare were found for PGPR No.41 strains, with 60 kg Phosphorus ha-1 treatments. After accelerated aging practices to achieve maximum germination index and vigor, seed rates and phosphorus requirement were more than standard conditions. Based on obtained results for the storage conditions, bacterial strains No. 41 had a better effect on increasing seed vigor than bacterial strains No. 9. To produce alfalfa seed with high vigor and obtain better results, use of optimum seed rates and phosphorus (6 and 30 kg.ha-1, respectively) along with PGPR (strain No. 41) could be considered in crop plants.


Effect of Harvesting Time and Drying Temperature on Soybean Seed Quality
Hossein Sadeghi, Hossein Heidari Sharifabad, Aidin Hamidi, Ghorban Nourmohammadi, Hamid Madani,
Volume 2, Issue 2 (2-2016)
Abstract

In order to evaluate the effect of seed moisture content at harvesting time and drying temperature on soybean seed germination characteristics, an experiment was conducted as factorial (2×3×2) based on Randomized Complete Block Design with three replications in Karaj and Moghan areas. The first factor was cultivar with two levels (Williams and L17), the second factor was seed moisture content with three levels (15, 20 and 25%) and the third factor was drying temperature with two levels (30 and 45 °C). Results show that the germination percentage of producing seeds in Karaj (81.3%) were higher than Moghan area (77.4%). The difference between the germination percentage of dried seeds at 30 and 45◦C with initial seed moisture content of 15% was about 5.5%, while this difference for seeds with 25% initial moisture content was about 18.5%. There was no significant difference between seedling vigor index of seeds with 15% moisture content of two cultivars that have been produced in Karaj, but at 20% moisture content, the seedling vigor index in Williams cultivar (139.7) was higher than L17 cultivar (107.3). The highest (51.42 µsm cm-1 g-1) electrical conductivity of seed leakage soluble was obtained from the L17 cultivar with 25% moisture content and 45◦C and the lowest (28.46 42 µsm cm-1 g-1) rate of it was observed in Williams cultivar with 20% moisture content and 30◦C. According to these results, we must harvest and dry soybean seeds at 30◦C when its moisture content reached under 20%.


Effect of Seed Priming with Gibberellic Acid and Salicylic Acid on Germination Characteristic and Seed and Seedlings Physiological Quality of Lentil (Lens culinaris)
Mohsen Azarnia, Abbas Biabani, Hamid Reza Eisvand, Ebrahim Gholamalipour Alamdari, Saeed Safikhani,
Volume 3, Issue 1 (8-2016)
Abstract

One of the important strategies for increasing germination speed and germination percentage, to produce high-quality seedling and plant optimal establishment is seed priming. In order to evaluate reactions of a lentil seed to priming duration and concentrations of the applied material as priming, a factorial experiment based on a completely randomized design with three replications was done in the agronomy laboratory of agriculture and Natural Resources College of Gonbad Kavous University in 2013. Factors included priming duration (4, 8 and 12 h) and various concentrations of the priming (hydro priming, hormonal priming by gibberellic acid and salicylic acid with the concentrations of 50, 100 and 150 ppm and non primed seeds). Results showed that the interaction effect of the concentrations and duration of the priming was significant on whole measured traits except the seed vigor index, germination percentage and seedling dry weight at 1% probability level. The lowest duration of germination (5, 10, 90 and 95%) obtained in the hydropriming treatment (2.72, 5.43 and 18.17 hour). The highest radicle fresh weight was observed in hydropriming treatment in three studied durations priming. In this study; the highest rate of germination obtained from GA50ppm during 12 hours. GA50ppm increased Germination percentage (98%). The greatest radicle length, shoot length and relative growth rate was obtained in the treatment of the gibberellic acid 100 ppm during 8 hours. All the average, gibberellic acid 100 ppm in 8h had an additive effect on the most of the measured traits of the lentil seed. Therefore, it can be introduced as the best mixture treatment.


The Effect of Pre-Chilling and Gibberellic Acid on Breaking Seed Dormancy of Two Medicinal Plants Species Silybum Mrianum and Citrulus Colocynthis
Almas Nemati, Hamid Sharifi, Mohammad Gerdakaneh, Zeynab Sharifi,
Volume 3, Issue 1 (8-2016)
Abstract

The seeds of two species (Citrulus colocynthis) and (Silybum mrianum) gathered from natural habitat located in the Koohdasht city (Lorestan province) and transferred to Kermanshah Agricultural and Natural Resources Research and Education Center in the summer of 2014. For each species, separate experiments in a completely randomized design with 14 treatments and 4 replications were done. Treatments included moist-chilling time (control, 10, 20, 30, 40, 50, 70 and 90 days at 4 °C), gibberellic acid concentration (200, 400, 600 and 800 PPM) and integrated treatment of gibberellic acid 400 ppm with moist-chilling for 30 days and 70 days. The results showed that for both species increasing of moist-chilling duration and concentration of gibberellic acid significantly increased germination percentage, germination rate and seed vigor index. The best breaking seed dormancy treatment was moist-chilling of 90 days for seeds of (Citruluus colocynthis) and gibberellic acid 800 ppm for (Silybum mrianum). The result showed that seeds of two species had the combination of physiological (related to seed inside inhibitors) and physical dormancy (related to hard coat).


An Investigation into Germination Patterns of Common Lambsquarters (Chenopodium album) in Reaction to Temperature, Salinity and Waterlogging Stress
Shahram Nazari, Reza Deihimfard, Javad Faraji,
Volume 3, Issue 2 (2-2017)
Abstract

Gaining insights into the germination and emergence patterns of weeds as well as the factors which have an impact on these patterns is beneficial for weeds management programs. In order to investigate the effect of temperature, waterlogging and salinity on germination and emergence of common lambsquarters, three separate experiments were conducted, adopting a completely randomized design with four replications. The results of the temperature experiment showed that the highest germination percentages, which were 87, 93 and 88%, were obtained in the temperature range of 15, 20 and 25°C, respectively. Maximum values of germination rate, radicle length, plumule length, and seedling dry weight were obtained at 20°C. In addition, optimum seed vigor index of 796.29 was observed at 20°C. The results of the Regression Model showed that germination percentage decreased with an increase in waterlogging duration and halted after 8 and 10 days of consecutive waterlogging. Mean comparisons revealed that radicle and plumule length, seedling dry weight and vigor index decreased significantly by increasing the period of waterlogging. Salinity adversely affected germination percentage, germination rate and seedling dry weight of common lambsquarters. These factors were at their highest amounts in the control and 50 mM NaCl treatments. A downward trend was observed in these factors as NaCl concentrations increased and finally the germination process stopped in concentrations ranging from 300 to 400 mM NaCl. Radicle and plumule length also decreased from 10.51 and 9.23 cm in the control treatment to 3.57 and 2.47 cm at 250 mM NaCl. Overall, the results revealed that the maximum seed vigor index of 851.84 was obtained in the control treatment and seed vigor halted when the salinity level increased to more than 250 mM NaCl. Finally, the results showed that optimum temperature for germination of common lamsquarters was 20 °C and the existence of salinity and waterlogging stress can decrease growth indices of this weed at germination and seedling stages.


Efficiency of Chemical and Mechanical Priming in Breaking Seed Dormancy and Germination Traits of Malva (Malva neglcta)
Farzad Mondani, Ashkan Jalilian, Atusa Olfati,
Volume 5, Issue 1 (9-2018)
Abstract
Extended abstract
Introduction: Malva (Malva neglecta) is one of perennial plants of the Malvaceae family. One of the most important mechanisms for survival of the plants is dormancy, rest or distance in germination and growth; in this case, despite favorable conditions for germination, the seed remains at rest for an indefinite period of time. Seed dormancy is a consistent feature in some seeds, especially weed seeds to optimize distribution of germination over time. Seed dormancy has a very important role in ecological management. The cause of the physical dormancy lies in skin cells outside tier structure that is impermeable to water. In physical dormancy, the seed coat is so hard that it does not allow the embryo to grow during germination. The chemical dormancy of the plants seeds is caused by the presence of inhibitor substances in the outer shell of many fruits and seeds and may also be due to an Enamel layer that blocks the exchange of oxygen. It goes without saying that understanding the ecology of weed germination and dormancy can contribute to long-term management. Therefore, this study was conducted to determine the effects of breaking seed dormancy and the impact of chemical and mechanical treatments on the germination of the Mallow seeds.
Materials and Methods: In order to recognize the effects of chemical and mechanical treatments on breaking seed dormancy and some of the most important features of seed germination of Malva, the experiment was conducted based on a completely randomized design with 4 replications at Crop Physiology Lab, Razi University, during 2016. Treatments were distilled water (control), sulfuric acid 98% (for 2, 3 and 4 minutes), potassium nitrate 3% (for 3, 4 and 7 days), hydrogen peroxide 30% (for 2, 3 and 4 minutes) and scarification with sandpaper and prechilling (for 1, 2 and 3 weeks). Germination percentage, germination rate, length and dry weight of hypocotyl, length and dry weight of radicle, seedling total dry weight and vigor index were evaluated. Group comparisons, analysis of variance and comparison of means were run based on LSD at 5% level, using SAS software (version 9.4).
Results: The results showed that the highest and the lowest germination percentage were 82% and 5% in scarification with a chilling for 3 weeks and control treatments, respectively. The results of treatment group comparisons also showed that using scarification with a chilling had the greatest impact on seed dormancy breaking. The most hypocotyl length (34.92 mm), hypocotyl dry weight (2.60 g), seedling dry weight (3.29 g) and seed vigor index (58.13) were observed in scarification with a chilling for 3 weeks. The highest germination rate (5.21 in day), radicle length (34.92 mm) and radicle dry weight (0.85 g) also belonged to sulfuric acid 98% for 2 minutes. It seems that seed dormancy of Malva was a combination of physiological and physical dormancy, because the effectiveness of the treatments evaluated in both metabolic and physical processes brought about the increase in the seed germination percentage.
Conclusion: Out of the treatments examined and given the results of group comparisons, scarification with sandpaper and prechilling had the most effect on breaking Malva’s seed dormancy. As scarification with chilling had the main role in breaking seed dormancy, it could be said that the dormancy is physiological and factors contributing to this dormancy are the embryo, the existence of inhibiting factors or both. The results indicated that the germination of Malva (Malva neglcta) seeds mechanically scratched with scarification increased. Therefore, seed dormancy is due to hard coated seeds. The seed coat is as one physical barrier against growth of embryo or radicle that inhibits absorption of water and gas exchanges.
 
 
Highlights:
1- Investigating dormancy breaking and germination traits of neglcta species of Malva.
2- Evaluation of efficiency of different chemical and mechanical treatments in the germination traits of Malva.

Effect of Methyl Jasmonate Pre-Treatment on Germination Indices and Biochemical Traits of Stevia Seedlings (Stevia rebuadiana) under Salt Stress
Elnaz Mohamadian, Hormozdyar Kianmehr, Hojjat Ataei Somagh, Neda Azad Nafas Mahjor, Fatemeh Safari, Arezo Safarzadeh,
Volume 5, Issue 1 (9-2018)
Abstract
Extended abstract
 Introduction: Stevia is a perennial short day plant, belonging to the Asteraceae family. It is also called sugar leaf. Poor germination of this plant serves as a barrier for its planation on a large scale, which contributes to its scarcity and expensivenss as a medicinal herb. In many plants, seed germination is sensitive to salinity, which determines the survival of the plants in saline soils. High levels of soil salinity can significantly reduce germination and seedling growth due to the effects of high osmotic potential and ion toxicity. Jasmonates represent new plant growth regulators that play an important role in increasing the resistance of plants to environmental stresses, including salinity stress. Therefore, this experiment was conducted to study the effect of pre-treatment of seed with methyl jasmonate on germination indices and biochemical traits of stevia, as a medicinal herb, under salinity stress.
Materials and Methods: They study was conducted, adopting a completely randomized design with three replications in the year 2016 in the Professor Hassabi’s Laboratory of Plant Biology, Islamic Azad University, Islamshahr Branch. The factors were pre-treatment of methyl jasmonate in 5 levels (0, 2.5, 5, 10 and 15 μM) and salinity stress at 4 levels (0, 3, 6 and 9 dS m-1). At the end of the experiment, germination traits percentage and germination rate, mean germination time, germination value, seedling length, seedling index, total chlorophyll, proline, activity of the enzyme catalase, peroxidase and superoxide dismutase were measured.
Results: The results of the study showed that effects of salinity stress, methyl jasmonate and interaction between salinity and methyl jasmonate were significant on the germination percentage and germination rate, mean germination time, germination value, seedling index, total chlorophyll, proline and catalase enzyme activity. Seed priming with 5 μM methyl jasmonate at salinity level with electrical conductivity of zero ds/m, had the highest germination percentage and rate, germination value, seed vigor index, and total chlorophyll content. Increases in salt stress and methyl jasmonate increased the activity of catalase enzyme. Salinity reduced germination index and seedling stoichiation and increased activity of peroxidase and superoxide dismutase enzymes. However, seed priming with methyl jasmonate improved seed germination through germination percentage, germination rate and seed vigor index and moderated the effects of salt stress.
Conclusions: Given the results of this study, it could be said that methyl jasmonate, as a potent inhibitor, can reduce the negative effects of salinity and by increasing germination indices such as germination percentage and germination rate, it can be effective in improving the growth of Stevia. Of course, further research can produce more definitive results.
 
 
Highlights:
  1. Salinity had a negative effect whereas methyl jasmonate had a positive effect on germination indices and activity of antioxidant enzymes of Stevia seeds.
  2. Application of 5 μM of methyl jasmonate, as a pre-treatment, can be effective in improving the growth of the stevia plant and reducing the negative effects of salinity.

Effect of Seed Priming with ZnSO4 and FeSO4 on Dormancy Break Optimization and Germination Traits of Shallot (Allium hirtifolium)
Elahe Hoseinpur Askarian, . Ali Abbasi Surki, Abdolrazagh Danesh Shahraki,
Volume 6, Issue 1 (9-2019)
Abstract


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

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 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.

Comparison of Ecological Aspects of Seed Germination of Syrian mesquite (Prosopis farcta) Ecotypes of Khuzestan and Fars Provinces
Ahmad Zare, Elham Elahifard, Zahra Asadinejad,
Volume 7, Issue 2 (3-2021)
Abstract
  
Extended Abstract
Introduction: Syrian mesquite is introduced as a weed in wheat and barley fields, saffron, cotton and vegetables, and in orchards. The spread of this weed in different climates raises the question of how much native plant conditions can affect germination characteristics. Therefore, the purpose of this study was to evaluate the effect of native plant conditions on germination characteristics in response to environmental stresses (temperature, salinity, and drought).
Materials and Methods: To investigate dormancy elimination and germination response thresholds of two Syrian mesquite ecotypes (Khuzestan and Fars) to environmental factors (temperature, salinity, and drought), four separate experiments were carried out as factorial based on completely block design with three replications at Agricultural Sciences and Natural Resources University of Khuzestan. Treatments included immersion the seeds with concentrated sulfuric acid (96%) (0, 10, 15, 20, 25, and 30 min), different temperature (0, 5, 10, 15, 20, 25, 30, 35, 40, and 45 °C), salinity levels (0, 100, 200, 300, 400, 500, and 600 mM), and different levels of drought stress (0, 0.2, 0.4, 0.6, 0.8, 1 and 1.2 MPa).
Results: The time required for immersion of seeds in sulfuric acid to dormancy breaking for two ecotypes was different. The estimated parameters indicated time of immersion in sulfuric acid to reach 50% germination in the Khuzestan ecotype (11.38 min) was longer than the Fars ecotype (8.10 min). The Khuzestan ecotype was also able to germinate (45%) at 40 ° C, whereas germination in the Fars ecotype was stopped at this temperature. Germination rate and cumulative germination percentage at temperatures below 25 ° C were higher in Fars ecotype than in the Khuzestan ecotype. The results of the salinity experiment showed that 50% reduction in seed vigor index, final germination percentage, and germination rate in the Fars ecotype were 167.48, 404.46, and 307.02 mM respectively and in the Khuzestan ecotype were 0.89. 229, 380.16, and 299.57 mM, respectively. For drought treatments, 50% reduction in final germination percentage, seed vigor index, and germination rate in Fars ecotype were -0.50, -0.38, and -0.39 MPa, respectively, and in Khuzestan ecotype were -0.46, -0.46, and -0.50 MPa, respectively.
Conclusion: Overall, the results showed that native plant climatic conditions (latitude and longitude, elevation, rainfall, and temperature) can affect the degree of seed dormancy, resistance to environmental stresses such as temperature, salinity, and drought.

 
Highlights:
1- Seed germination response thresholds of two ecotypes of Fars and Khuzestan for exposure to temperature and drought and salinity stresses were compared.

Investigating the germination characteristics of Chickpea (Cicer arietinum) in response to titanium dioxide nanoparticles priming and drought stress
Roya Ghorbani, Ali Movafeghi, Ali Ganjeali, Jafar Nabati,
Volume 9, Issue 1 (9-2022)
Abstract
Extended Abstract
Introduction: Drought stress, as abiotic and multidimensional stress, has severe effects on plant growth. One of the new approaches in the management of drought stress is the use of nanoparticles. Nanoparticles infilterate the seeds and increase nutrient and water uptake and ultimately, improve germination. The present research was conducted to evaluate the effects of titanium dioxide nanoparticles on chickpea plant germination factors to modify the negative effects of drought stress.
Materials and Methods: A factorial experiment was conducted in a completely randomized design with four replications on chickpea seeds of Arman cultivar in the Plant Sciences Research Institute of the Ferdowsi University of Mashhad in 2019. Seeds were primed with concentrations of 0, 5, 10, 15, and 20 mg L-1 titanium dioxide for 24 hours. The seeds were cultured in sterilized Petri dishes. Drought stress was applied using polyethylene glycol 6000 with 0, -2, -4 and -8 bar osmotic potentials.
Results: The analysis of variance results showed that the interaction effect of drought stress and titanium dioxide nanoparticles was significant on germination rate, the number of normal seedlings, seed vigor index, germination index, length of seedling, radicle length, and radicle dry weight. All germination traits were inhibited as a result of drought stress. On the other hand, the presence of titanium dioxide nanoparticles partially decreased this inhibition in some traits. Germination percentage, germination rate, normal seedling percentage, seed vigor index, germination index, epicotyl length, radicle length and radicle dry weight decreased as a result of stress.
Conclusion: At all drought stress levels, the concentration of titanium dioxide nanoparticles up to 20 mg L-1 significantly improved traits such as germination percentage, seed vigor index, epicotyl length, and epicotyl dry weight. It seems that nanoparticles can stimulate cell activity and increase the transformation of reserves to translocatable material and consequently, improve germination characteristics. Thus, the application of titanium dioxide nanoparticles up to a concentration of 20 mg L-1 can partially reduce the negative effects of drought stress on the germination characteristics of chickpeas.

Highlights:
1- Germination percentage and seed vigor index of chickpea increased with the application of titanium dioxide nanoparticles up to 20 mg l-1 at all drought stress levels.
2- The radicle length and dry weight of chickpea increased by titanium dioxide nanoparticles.
3- The negative effects of drought stress on chickpea seed germination decreased by titanium dioxide nanoparticles.

The effect of mesoporous titanium dioxide nanoparticles on germination traits of black saxaul seeds (Haloxylon aphyllum (Minkw.) Iljin) under drought stress
Seyedeh Tina Mousavi Kani, Davoud Kartoolinejad, Zohreh Bahrami, Ali Asghar Zolfaghari, Elahe Nikouee,
Volume 9, Issue 1 (9-2022)
Abstract
Extended Abstract
Introduction: Nowadays, due to land use change and destruction of natural resources induced by human activities, attention to desertification has immensely become widespread. One of the most important species for biological rehabilitation of desert areas on a large scale is the hawthorn plant. Hawthorn is a plant belonging to the family Amaranthaceae, the two species of which are called white saxaul (Haloxylon persicum Bunge ex Boissier & Buhse) and black saxaul (Haloxylon aphyllum (Minkw.) Iljin) are more notorious and widespread in Iran. These plants own extensive root systems and stabilize running sands. The aim of this study was to investigate the effect of mesoporous titanium dioxide nanoparticles on germination traits of black saxaul seeds under drought stress, as an important species in desert areas.
Materials and Methods: The experiment was performed as a factorial experiment in a completely randomized design with 3 replications. Experimental treatments included five titanium nano dioxides with concentrations of 0, 25, 50, 100 and 200 mg / l and six drought stress levels including 0, -4, -8, -12, -16 and -20 bar. After nanopriming, black saxaul seeds were subjected to drought stress for 15 days in a germinator at a temperature of 20 °C with four replications. After germination, in each of the treatments, germination percentage (GP), germination rate (GS), mean germination time (MGT) and seed vigor index (VI) were calculated.
Results: The results of two-way ANOVA and mean comparison of germination indices showed that the highest germination percentage (74%) belonged to the zero level of stress treatment with a concentration of 200 mg/l and the lowest one (3%) belonged to -20 bar treatment with 25 and 200 mg/l nano-titanium dioxide. With increasing drought stress intensity from zero to -20 bar level, germination rate decreased from 7.01 to 0.43 seeds per day. The highest amount of seed vigor index at zero drought level belonged to the treatment of 200 mg/l concentration of nano-titanium, with a rate of 325.77.
Conclusion: The results showed that germination indices and initial growth of black saxaul seeds decreased in all primed and unprimed treatments with increasing drought stress, and nanopriming with titanium dioxide had a positive effect on seed germination traits.

Highlights:

1- Seed priming using mesoporous nano-titanium dioxide improved the germination percentage of black saxaul seeds under drought stress.
2- The concentration of 200 mg/l of mesoporous nano titanium dioxide revealed a better effect on seed germination index, mean germination time, germination rate and percentage
3- Seed nano priming using titanium dioxide did not have much effect on the growth characteristics of black saxaul seedlings at higher levels of drought stress.
 
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