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Showing 9 results for Omidi

Kazem Badeleh, Mehdi Aghighi Shahverdi, Haeshmat Omidi,
Volume 1, Issue 2 ((Autumn & Winter) 2015)
Abstract

To evaluate the effect of priming on seed germination of Cucurbita pepo in drought stress conditions, a factorial experiment was conducted as completely randomized design with three replications. Treatments included drought stress at five levels of osmotic potential (zero, 0.3, 0.6, 0.9 and 1.2 MP), priming at levels of GA3 (250 ppm to 24 hours), KNO3 (0.2% for 24 hours) Hydro prime (H2O) (to 24 hours) and control. The results showed that priming effect was significant on germination percentage, germination rate, mean daily germination, the average time required for germination and germination rate index. A significant difference was found between drought stress on seed germination rate. In addition, the interaction of seed priming and drought stress was significant on all traits (germination percentage, germination rate, average daily germination, the average time required for germination, germination rate daily, the coefficient of germination rate and the seed vigor). Seed priming, particularly in severe drought stress levels, led to significant increase in mean germination percentage, germination rate and seed vigor. Furthermore, the results of our study indicated that Cucurbita pepo seed priming had partial resistance to drought. Gibberellin acid in the first grade and the hydro priming in second grade can improve the germination and growth of the seedlings under drought stress.

Razieh Sarami, Heshmat Omidi, Abdol Amir Bostani,
Volume 3, Issue 2 ((Autumn & Winter) 2017)
Abstract

The present study was conducted to investigate the efficiency of hormonal pretreatment on increasing germination and early growth of seedling in the Seed Technology Laboratory of Shahed University in 2015 as a factorial experiment, adopting a completely randomized design with 4 replications. The treatments were: 5 levels of IAA (indole-3-acetic acid) namely, zero, 0.1, 0.5, 1 and 1.5 mg/L and 5 levels of PBA (Tetrahydro pyranyl ­benzyl­ adenine), which were zero, 0.5, 1, 1.5 and 2 mg/L. Analysis of variance showed that the use of the two hormones and their interactions had a significant effect on all traits such as seed germination, biomass, leaf relative water content and photosynthetic pigments. The highest percentage of germination (66.66%) was obtained in 1.5 mg/L IAA with 1 mg/L PBA. 0.5 mg/L PBA and in 0.1 mg/L IAA the longest shoot (1.28 and 1.17 cm, respectively) was obtained. Germination coefficient decreased by about 12.5% by increasing IAA from 0.1 to 1.5 mg/L. The greatest relative water content (42.73% and 37.38%) was obtained with 0.5 mg/L PBA and 1.5 mg/L IAA, respectively. Combination of IAA+PBA (0.1+0 mg/L) had a positive effect on both the length of the root and seedling. The high concentration of PBA and the lowest amount of IAA had similar results in terms of plant biomass. The highest plant biomass (4.33 mg) was obtained in seeds treated with 2 mg/L of cytokinin and 0.1 mg/L of auxin. Photosynthetic pigments were also affected by these two hormones through the IAA was more effective than PBA. The finding was that auxin and cytokinin increase germination and improve the morpho-physiological indicators and thus increase the yield of Stevia.
 


Mehdi Aghighi Shahverdi, Heshmat Omidi, Sayed Esmail Mousavi,
Volume 3, Issue 2 ((Autumn & Winter) 2017)
Abstract

For the purpose of evaluating the effect of chitosan on seed germination and some biochemical characteristics of the milk thistle herb in the conditions of salinity, an experiment was conducted as factorial in a completely randomized design (CRD) with three replications in the Laboratory of Seed Science and Technology of Shahed University, Tehran in 2015. Experimental factors comprised salinity levels (0, 4, 8 and 12 dS.m-1) and different levels of Chitosan (0, 0.25, 0.5, 0.75 and 1 percent). The results showed that salt stress reduced germination percentage, germination coefficient, germination speed, weight and length vigor index, radical, plumule and seedling length and total biomass and increased mean germination time. Seed priming with chitosan up to 0.5% concentration increased germination coefficient, weighted index vigor and plumule length. The highest amounts of total chlorophyll and total protein were obtained in seed priming with 0.5% chitosan levels in zero salinity level (control). By increasing salinity levels, the activity level of catalase and peroxidase increased, so that the highest level of the activity of these two enzymes was obtained in the salinity level of 12 dS.m-1 in pre-treatment with 0.5% Chitosan. The results showed that seed priming with chitosan of 0.5% could reduce harmful effects of salt stress on some traits of milk thistle seedlings and could even improve their growth.
 


Vahid Mansouri Gandomany, Heshmat Omidi, Mohammad Rezaei Charmahin,
Volume 3, Issue 2 ((Autumn & Winter) 2017)
Abstract

In order to investigate the effect of pretreatment of chitosan biological compounds on seeds of soybean (Glycine max L. cv. Williams) under salt stress conditions, a factorial experiment was conducted, adopting a completely randomized design with three replications at Shahed University in 2015. Factors examined included the combination of chitosan at three levels (0, 0.25 and 0.5 the weight-volume) and salinity at 4 levels (0, 5, 5.7 and 10 dS/m). The results showed that the interaction of chitosan and salinity had a significant impact on seed germination characteristics such as germination percentage, germination rate, mean germination time, normal seedling and physiological characteristics such as proline and soluble sugars of shoots. In contrast to salt stress increase of 30%, and an increase of 24 and 35% of proline and soluble sugars of the shoot, pretreatment of chitosan (0.25%) improves seedling germination characteristics of soybeans. Given the impact of the treatments of chitosan on seed germination and seedling growth of soybean, it is possible to introduce 0.25% W/V chitosan as a treatment to deal with conditions of salinity.
 


Ali Mansouri, Heshmat Omidi,
Volume 5, Issue 1 ((Spring and Summer) 2018)
Abstract

Extended abstract
Introduction: Quinoa, with the scientific name (Chenopodium quinoa Willd), belongs to the Spencer family. Seeds vigor can be improved with a variety of seed priming methods. In this method, the seeds are soaked in water or various osmotic solutions and then dried to the original moisture. After priming treatment, seeds are stored and cultivated as untreated seeds. Potassium nitrate is the most frequently used chemical for the purpose of increasing seed germination and is recommended by the Society of Official Seed Specialists and the International Association of Seed Testing for germination experiments of many species. In recent years, the use of nanoscale materials has been of great interest to researchers. Chitin, one of the most abundant polysaccharides in nature, is a polymer chain of N-acetyl glucosamine and is associated with other proteins and other organic compounds, and numerous industrial, pharmaceutical and agricultural applications have been reported for it. The present study was carried out to investigate the effects of chitosan nanoparticles and potassium nitrate on some morphological characteristics, germination characteristics, chlorophyll content and relative humidity of quinoa plant.
Materials and Methods: In order to investigate the effect of pretreatment of quinoa seeds with chitosan nanoparticles and potassium nitrate solution on the early stages of germination, a factorial experiment was conducted in a completely randomized design with four replications in Seed Processing Laboratory, Faculty of Agricultural Sciences and Natural Resources, Shahed University, Tehran, Iran. Experimental treatments consisted of priming with chitosan nanoparticles in 4 levels (no primers, 0.01, 0.20 and 0.04% w / v) and potassium nitrate in 3 levels (no primers, 0.2 and 0.5% Weight percent) and hydroperime for 2 hours at 25° C. For each replicate of every treatment 100 seeds, using standard priming methods, were treated with the materials mentioned above and were dried in a petri dish on Watman paper No. 1 at 20 ± 1 ° C and relative humidity of 70% and 16 hours of daylight and 8 hours of darkness to make germination work. After that, germination percentage, root length, shoot length, germination coefficient, Allometric coefficient, relative water content, chlorophyll content a and b were measured, using standard methods.
Results: Seed treatment with 0.2% potassium nitrate solution increased germination by 9% and treatment with chitosan 0.01% increased germination by 14%, compared with the non-primer treatment. The priming treatment with a 0.5% solution of potassium nitrate and 0.01% chitosan increased germination by 36%, compared to the non-primer treatment. Potassium nitrate increased root length by 25% and shoot length by 10%. In addition, chitosan 0.01% increased the root length by 6%, and seeds with chitosan 0.02% and potassium nitrate 0.2% increased the root length by 32%. The effects of potassium nitrate, chitosan and their interaction on chlorophyll a and b were significant at 1% probability level. The highest levels of chlorophyll a were obtained in 0.02% chitosan and 0.2% potassium nitrate. This formulation increased the chlorophyll a content by 33%. The highest amount of chlorophyll b was obtained by applying 0.01% chitosan and 0.5% potassium nitrate.
Conclusion: The results of this study showed that treatment with 0.01% w/v chitosan and 0.5% w/v potassium nitrate resulted in the highest germination percentage, chlorophyll content a and b, relative water content, and stem length. Treatment with 0.02% chitosan and 0.2% potassium nitrate resulted in the highest allometric coefficient and root length.
 
 
Highlights:
  1. Chitosan nano particle and potassium nitrate increase quinoa germination.
  2. Chitosan nano particle and potassium nitrate increase the content of chlorophyll a and b.

Alireza Gorzi, Heshmat Omidi, Abdolamir Bostani,
Volume 6, Issue 2 ((Autumn & Winter) 2020)
Abstract



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

Seyyed Esmaeil Mousavi, Heshmat Omidi, Ayatollah Saeedizadeh, Mehdi Aghighishahverdi,
Volume 7, Issue 2 ((Autumn & Winter) 2021)
Abstract

Extended Abstract
Introduction: Salinity is one of the most harmful factors in the arid and semi-arid regions in the world that influences crop production. Micro-organisms can play an important role in adaptation strategies of plants to stress and by producing of plant growth promotion hormones such as cytokinin, gibberellic acid, auxin, amino acids, and vitamins of B groups help to more growth of the plant and have an important role in increasing of tolerant in plants in unsuitable environments.
Material and Methods: This experiment was established as factorial in a completely randomized design with three replicates at Shahed University of Tehran. The treatments included salinity in four levels (0, 40, 80, and 120 mM NaCl) and biological pre-treatment at eight levels (control: non-inoculation), inoculation with Trichoderma harzianum fungus strain BI, with inoculation with azotobacter bio-fertilizer, inoculation with phosphate bio-fertilizer, inoculation with both bio-fertilizer, a combination of fungus and azotobacter bio-fertilizer, a combination of fungus and phosphate bio-fertilizer, inoculation with fungus and both bio-fertilizer). In this experiment, germination indices, photosynthetic pigments, proline, sodium, and potassium amount, starch, carbohydrate, electrical conductivity, and soluble protein were studied.
Results: The result showed that the interaction effect of biological pre-treatment and salinity was significant on all indices except chlorophyll b and anthocyanin. Treatment of phosphate bio-fertilizer had maximum positive effect on germination percent with increasing salinity. In the co-application of fungus and azotobacter bio-fertilizer treatment, the amounts of chlorophyll a, b, and total chlorophyll in different levels of salinity were more than the other treatments and were incremental with further increasing of salinity level. The highest amount of potassium (4.10 mg/g FW) obtained in the co-application of a fungus with azotobacter bio-fertilizer under 40 mM of salinity and showed 22.02 percent increase in comparison to control. With rising salinity, fungus treatments were the most effective in preventing more increasing sodium amount and azotobacter bio-fertilizer in preventing more reducing potassium. The number of soluble proteins was the highest amount (13.09 mg/g FW) in the co-application of fungus and both bio-fertilizer and showed 38% increase compared to control at the same level of salinity.
Conclusion: The uses of microorganisms reduced the negative effect of salinity and led to the increase of potassium in shoots. Also, utilization of microorganism led to lower electrical conductivity at the highest salinity level compared to control and thus, positively affected germination.
 

Highlights:
1- The effect of bio- primed bacteria and fungus on physiological traits of Pumpkin was investigated seedlings under salinity.
2- Threshold of tolerance of pumpkin seedlings to salinity was improved by increasing K content and reducing Na under bio- primed treatments.
3- Osmolite components of pumpkin seedlings increased under bio- primed treatments.

Marzieh Ababaf, Heshmat Omidi, Abdolmehdi Bakhshandeh,
Volume 7, Issue 2 ((Autumn & Winter) 2021)
Abstract

Extended Abstract
Introduction: Catharanthus roseus is regarded as a medicinal ornamental plant. This plant has anti-cancer, anti-hypertensive, anti-diabetes, and antimicrobial properties. Catharanthus has a fairly long vegetative period due to its slow initial growth. The long growth period of the plant is considered one of the limitations in its cultivation on a larger scale. By using plant growth regulators such as salicylic acid (SA) in the imbibition phase and pre-treatment, an increase in seed activity and the seedling growth of many crops is observable. Also, jasmonic acid (JA) plant growth regulators play an important role in seed germination and plant growth. Regarding the long growth period of this plant, the small size of the seed, and poor establishment in the field with semi-heavy and heavy textured soils, the present study aimed to evaluate the effect of seed priming with SA and JA in different concentrations and periods on improving Catharanthus roseus seed germination indices.
Materials and Methods: The studies were conducted as a factorial experiment based on a completely randomized design with three replications at the Laboratory of Seed Science and Technology of Shahed University, Tehran, in 2017. Treatments included five different concentrations of SA (0, 0.01, 0.1, 0.5, and 1 mM), concentrations of JA (0, 1, 10, and 100 µM) and five periods of time (0, 6, 12, 24, and 48 hours). At the end of the experiment (10 days) traits such as germination percentage, germination rate, mean germination time, mean daily germination, germination value, seed length vigor index, seed weight vigor index, seedling dry weight, shoot dry weight, radicle dry weight, radicle length, shoot length, and seedling length were measured.
Results: The results indicated that the effect SA, JA, and time were significant on germination percentage, germination speed, mean germination time, mean daily germination, germination value, seedling length, seedling length vigor index, seedling weight vigor index, and radicle dry weight. The best times for pre-treatment with SA were 24 and 48 hours. Among the applied concentrations of SA, 0.5 and 1 mM concentrations showed the best results. Also, the best time and concentration for pre-treatment with JA were 12 and 24 hours and 10 µM.
Conclusions: The results of this study showed that using SA and JA for seed priming improved seed germination components. In addition to the pre-treatment concentrations of SA and JA, the duration of seed contact with growth regulators is important. It was observed that there was a significant difference among the different priming times, therefore, it can be stated that seed pre-treatment time is one of the important factors of seed priming, and the determination of proper priming time prevented the negative effect of pretreatment on germination and seedling growth in primed seeds.

Highlights:
1- The optimum concentrations of salicylic acid and the priming time of the seed were determined.
2- The appropriate concentrations of jasmonic acid and the optimum time for pretreatment of seed were determined.
3- The effect of growth regulators of salicylic acid and jasmonic acid on seed germination indices was evaluated.

Marziyeh Ababaf, Heshmat Omidi, Abdolmehdi Bakhshandeh,
Volume 10, Issue 1 ((Spring and Summer) 2023)
Abstract

Extended Abstract
Introduction: Various strategies have been used to improve growth and productivity of crops through genetic approach, genetic engineering, and breeding. However, economic feasibility and ease of use can pave the way for the application of priming techniques as "stress relievers" in agricultural production. The aim of this study was to evaluate the ability of priming Catharanthus roseus seed with phytohormones of salicylic acid and Jasmonic acid under drought stress to reduce the effect of water limitation during the germination.
Materials and Methods: Two separate studies were conducted as a factorial experiment based on a completely randomized design with three replications at the Laboratory of Seed Science and Technology of Shahed University, Tehran. In the first experiment, treatments included priming in two levels of SA (0.5 and 1mM) and priming duration in two levels (24 and 48 hours), and drought stress with polyethylene glycol 6000 in 6 levels (0, 0.1, 0.5, 1, 1.5 and 2 Mpa). In the second experiment, treatments included JA (10 µM), priming duration in two levels (12, and 24 hours) and drought stress in levels six (0, 0.1, 0.5, 1, 1.5, and 2 Mpa). Dry seeds (without pretreatment) were considered as control.
Results: In this study, drought stress treatments -1.5 and -2 Mpa in the first experiment and -1, -1.5 and -2 Mpa in the second one had no germination. Seed priming with SA and JA improved the percentage of seed germination so that in the first experiment, the highest percentage of germination (97.33) was observed under stress-free conditions with the application of 0.5 mM salicylic acid for 48 hours, which was 12.2% higher than the control treatment. 0.5 Mm of SA treatment with 24 hours of priming showed the highest percentage of germination under drought stresses of -0.1 and -0.5 Mpa. However, under drought stress conditions of -1 Mpa, 0.5 mM SA+48 hours treatment was superior compared to other treatments of salicylic acid and time. In the second experiment, the highest percentage of germination (98.3) was in the concentration of 10 μM jasmonic acid during 24 hours of priming under stress-free conditions, which showed an increase of 40.4% compared to the control treatment.
Conclusion: The results of the present study showed the importance of salicylic acid and jasmonic acid during seed germination stage under drought stress. Seed priming with salicylic acid alleviated the damages caused by drought stress on germination and growth. The process of adaptation to stress started by jasmonic acid can be attributed to pretreatment with jasmonic acid before applying drought stress.

Highlights:
  1. The effect of priming Catharanthus roseus seeds with salicylic acid and jasmonic acid phytohormones on the germination characteristics of seeds under drought stress was investigated.
  2. Priming Catharanthus roseus seeds with salicylic acid improved the germination percentage and characteristics of seeds under drought stress.


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