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Showing 241 results for Type of Study: Research
Effect of Different Levels of Temperature and Drought Stress on Germination Characteristics of Roman Nettle (Urtica pilulifera)
Zakia Ibrahim Quchi, Gholamreza Mohsenabadi , Hamed Hassanpour ,
Volume 4, Issue 2 (3-2018)
Abstract

In order to investigate the effect of different levels of temperature and drought stress on seed germination parameters of nettle roman (Urtica pilulifera L.), an experiment was conducted as factorial in a completely randomized design with three replications at the Department of Agronomy, College of Agriculture, University of Guilan, in 2014. Treatments included different temperature levels (5, 10, 15, 20 and 25 °C) and drought stress levels (0 (control), -2, -4,-6 and -8 bars). The results showed that treatments and their interactions had a significant effect on germination percentage (GP), germination rate (GR), root length and root dry weight. The highest GP (88%), GR (1.8 seed/day) and root dry weight (0.06 g) were obtained as the result of the interaction between the temperature of 25°C and no-stress condition. In this study, with an increase in drought stress and a decrease in temperature, GP, GR, root dry weight, root length and shoot length decreased. The impact of drought stress on GR and GP was lower at 20°C, compared with the temperature of 25°C. A decrease in water potential from -4 to -6 bars at 20°C caused a reduction of 50% and 30% in GP and GR, respectively. However, these reductions at 25°C were 75% and 70%, respectively. According to the results, it could be stated that the significant reduction threshold of seed germination parameters was -2 bars.

 
Highlights:

  1. The germination characteristics of Roman nettle were studied under drought stress and temperature.
  2. In drought stress of -4 bars, germination percentage and germination rate decreased significantly.

The Effects of Different Priming Methods on the Storability and Germination under Salinity Stress in Rapeseed (Brassica napus) Line Karaj 3
Shirin Taghi Zoghi , Elias Soltani , Iraj Alahdadi , Reza Sadeghi ,
Volume 4, Issue 2 (3-2018)
Abstract

This study was conducted to study the effects of different priming methods on germination rate and percentage under salinity stress and to determine the stability of primed seeds. In order to accomplish this, three different experiments were conducted separately, including the experiment of water uptake, the experiment of salinity stress, and the experiment of storability of primed seeds. Priming treatments were five levels of control (unprimed), hydropriming (Hyd), priming with humic acid (HA), priming with salicylic acid (SA) and priming with gibberellic acid (GA). Salinity stresses were four levels of 0, 4, 8 and 12 ds/m of NaCl. The stability of prime seeds was investigated over a period of 226 days after priming. The results of water uptake showed that rapeseeds entered into the third phase of water uptake after 18 hours of hydration. The results of the salinity experiment showed that salinity levels of 12 and 0 ds/m had the lowest (74.3 %) and highest (83 %) germination percentage, respectively. In terms of germination rate, there were significant differences between GA (0.034 h-1), HA (0.036 h-1) and Hyd (0.036 h-1) with C (0.019 h-1) and SA (0.027 h-1). Generally speaking, primed seeds germinated better than control seeds at all levels of salinity. The storability of primed seeds and control seeds had no significant decrease during storage. Finally, it was concluded that seed priming increased the tolerance to salinity stress; in terms of storability, there was no significant difference between primed seeds and primed seeds could be stored in the same way as control seeds.

Highlights:

  1. At the current research, the stability of prime seeds was investigated for the first time.
  2. There was no significant difference between the storability of primed seeds and control (unprimed) at each sampling time (with an exception for SA).
  3. Primed seeds had better germination performance than control at the all salinity stress levels.
  4. Seed priming treatments using gibberellic acid, humic acid and hydropriming were the best compared with the other treatments.

Evaluation of Salinity Tolerance in allotetraploid Cotton (Gossypium sp.) Genotypes, Using Multivariate Statistical Methods and Stress Tolerance Indices at Germination Stage
Nafise Taghizadeh, Gholamali Ranjbar, Ghorbanali Nematzadeh, Mohammadreza Ramzanimoghdam,
Volume 4, Issue 2 (3-2018)
Abstract
Salinity is one of the most important factors limiting agricultural production. Cotton, as an oil-fiber plant, is one of the most important industrial plants and is sensitive to salinity, especially at germination and seedling stages. Therefore, in this study, 14 allotetraploid varieties of commercial and local cotton were selected. The study was carried out as factorial with a completely randomized design and three three replications, using the sandwich method. Germination tests were performed at three salinity levels of 0, 8 and 16 ds.m-1. Afterwards, root and shoot length, fresh and dry weight of root and shoot, germination percentage, allometric coefficient, seedling water percentage and seed vigor index were measured and stress tolerance indices were calculated based on yield (seedling dry weight) in stress and non-stress conditions. Given these indices, all cultivars were aalyzed at two levels of 8 and 16ds.m-1, using principal component analysis and biplot diagrams were drawn. Finally, the dendrogram classification of genotypes was plotted based on STI indices (stress tolerance index), SSI (stress susceptibility index), and the performance (dry weight plantlet) in stress and non-stress conditions. The result of variance analysis for genotype, salinity and salinity×genotype demonstrated that dry weight root, dry weight shoot, fresh weight root, stem length, vigor index seedling, allometric coefficient, dry weight seedling, and length seedling were significant in p-value 0.01, and fresh weight shoot, length root were significant in p-value 0.05. Clustering and the biplot of the genotypes based on STI and SSI indices at salinity levels of 8 and 16 ds.m-1 indicated that the Sepid and Giza genotypes were tolerant and that the Kashmar genotype was sensitive to salt levels at germination stage.
  
Highlights:
  1. The reaction of the cotton cultivars studied was different to levels of salinity stress.
  2. An increase in salt stress caused a significant reduction in the germination characteristics of cultivars of cotton studied.
  3. Bi-plot analysis and clustering based on STI and SSI indices turned out to be a suitable method for clustering cotton cultivars.

Reaction of Germination and Seedling Growth of Redroot Pigweed (Amaranthus retroflexus) to Salinity and Drought Stress
Goudarz Ahmadvand, Masoume Dehghan Banadaki, Javad Alimoradi, Sara Goudarzi, Sasan Ardalani,
Volume 4, Issue 2 (3-2018)
Abstract

Salt and drought are two major environmental stresses that affect growth and development of plants. In order to study the effects of sodium chloride and polyethylene glycol (6000) on germination characteristics and early seedling growth of redroot pigweed (Amaranthus retroflexus), two completely randomized designs with 4 replications were conducted at Weed Research Laboratory of Bu-Ali Sina University, Hamedan in 2015. The treatments were salt and drought stress as osmotic potential at six levels (zero (control), -2, -4, -6, -8 and -10 bar). The results showed that when stress increased, germination percentage, germination speed, radicle and plumule length, seedling length and seedling vigor index decreased significantly (p≤ 0.05). With an increase in the intensity of salt and drought stress from zero to -10 bars, redroot pigweed seed germination reduced about 96 and 100 percent, respectively, compared with the control. The highest seedling length in both stresses was observed in the control (7.71 cm) and by increasing stress intensity to -10 bars in both salinity and drought stresses, seedling length was reduced to 1.52 cm and 0 cm, respectively. Fitting of the three-parameter logistic model provided a successful estimation of the relationship between salt and drought stress levels and germination percentage of redroot pigweed as well as germination speed. This model showed that salinity and drought stress at -3.58 and -3.75 bars caused a 50% reduction in maximum germination percentage of redroot pigweed. In addition, 50% decrease in germination speed caused by salinity and drought stress was observed in -2.58 and -2.88 bars, respectively.

 
Highlights:

  1. The germination characteristics of redroot pigweed were studied under salt and drought stresses.
  2. Drought stress reduced germination percentage of redroot pigweed.

Effect of hydropriming and seed aging on seed germination and biochemical characteristics of pinto bean (Phaseolus vulgaris) seed under salt stress
Majid Ghanbari, Seyed Ali Mohammad Modarres-Sanavy, Ali Mokhtassi Bidgoli, Parniyan Talebi-Siah Saran,
Volume 4, Issue 2 (3-2018)
Abstract
This study was conducted to evaluate the effect of hydropriming and seed aging on germination and enzymatic properties of pinto bean under salinity stress as factorial based on a completely randomized design with four replications. Two groups of seeds (i.e., non-aged and aged seeds), two hydropriming treatments (i.e., hydro primed and unprimed seeds) and six salinity treatments (i.e., 0, 2, 4, 6, 8 and 10 dS/m) were the experimental factors. The results showed that the highest mean time and percentage of germination, plumule length and vigor were observed in the control (i.e., distilled water) and hydropriming treatments. Maximum root length and percentage of seedling water were obtained in the control (i.e., distilled water) and aged seed treatments. In addition, in terms of radicle dry weight, the highest amount was observed in salinity of 4 dS/m and non-aged hydro primed seeds. The highest plumule dry weight was observed in salinity of 6 dS/m and allometric index in salinity of 8 dS/m for non-aged seed and aged seed without hydropriming, respectively. An increase in the levels of salinity stress and aging the seeds increased the malondialdehyde and reduced the activity of germination, mean time and germination percentage, and seedling growth. Seed hydropriming reduced the peroxidation of the cell membrane and generally improved the speed and uniformity of germination, aged and natural seeds vigor under both salinity and optimum conditions. As a result, hydropriming can increase the tolerance of bean seeds to salinity at the germination stage and increase the germination capacity of stored seeds for cultivation.
 
Highlights:
  1. The effect of hydropriming on recovering the power of seed germination of pinto bean has been studied under the salinity condition.
  2. An attempt has been made to determine the effect of hydropriming on increasing the tolerance of pinto bean seeds to storage and salinity stress condition.
  3. The effect of pinto bean storage on biochemical changes and enzyme activity has been studied in salinity stress condition.

A Study into the Effects of Salt Stress on Germination Components of Different Wheat (Triticum aestivum) Cultivars
Ali Namvar, Raouf Seyed Sharifi, Hashem Hadi,
Volume 4, Issue 2 (3-2018)
Abstract

In order to study the effects of different levels of salinity on germination components of wheat cultivars, a factorial experiment was conducted based on a completely randomized design with three replications. Experimental factors were wheat cultivars at eight levels (Saysons, Gaspard, Finkan, MV-17, Chamran, Sardari, Atila-4 and Azar-2) and six levels of salinity (0, 25, 50, 100, 150 and 200 mM NaCl). The results indicated that salinity had significant effects on all of the traits studied (i.e., radicle length and dry weight, plumule length and dry weight, remaining seed weight after germination, seedling weight, the longest radicle and plumule, number of radicle per seed, ratio of radicle weight to plumule weight and rate, and uniformity and percentage of germination). All of these traits declined with an increase in the salinity (except the ratio of radicle weight to plumule weight, remaining seed weight after germination and seedling weight). The highest ratio of radicle weight to plumule weight, remaining seed weight after germination and seedling weight were recorded in the salinity of 200 mM NaCl. The cultivars showed significant effects on all of the traits studied (except remaining seed weight after germination and seedling weight). Chamran cultivar showed the highest number of radicle per seed, the ratio of radicle weight to plumule weight, rate and percentage of germination. The highest radicle length and the longest radicle were obtained from the Sardari cultivar while in Azar-2 cultivar it was vice versa in plumule. Atila-4 cultivar showed the highest radicle and plumule weight. It seems that compared with other cultivars, out of the cultivars studied, Chamran, Azar-2, Sardari and Atila-4 were more resistant to salinity stress.

 
 Highlights:

  1. Introduction of wheat cultivars with more tolerance to salinity conditions at germination stage.
  2. Study of eight different wheat cultivars in terms of germination indices under salinity stress conditions.

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.

Effect of Different Primings on Germination and Growth Parameters of Rice (Oryza sativa) Seeds during Drought Stress, as Compared with Silver Nanoparticles
Mahnaz Aghdasi, Pooyan Mehrabanjoubani, Tahereh Nezamdoost, Fatemeh Tamaskani,
Volume 4, Issue 2 (3-2018)
Abstract

The present study sought to compare the effect of seed priming by hydropriming, ascorbate and calcium chloride (CaCl2) versus different concentrations of silver nanoparticles on two Iranian rice cultivars (Hashemi and Shiroodi) under drought stress. The experimental design, which was factorial, was completely randomized. The first factor was control (without priming), hydro-priming, 20 mg.L-1 calcium chloride, 20 mg.L-1 ascorbates and 20, 40 and 80 mg.L-1 of silver nanoparticles. The second factor was the drought stress, including control, -1.48 and -4.91 bars created by polyethylene glycol 6000 solutions. In plants without drought stress, the time required to reach 50% germination (T50) reduced to 34 and 54 percent under ascorbate and CaCl2 priming in the Hashemi and Shiroodi cultivars, respectively.  In the drought stress condition, ascorbate and hydropriming pretreatments decreased T50 and the time required to reach 90% germination (T90) more than silver nanoparticles, especially in the Shiroodi cultivar. On the other hand, in comparison with other pretreatments, CaCl2 had an important role in increasing the growth factors in all of the drought stress treatments. Although 40 mg.L-1 silver nanoparticles increased the growth factors to some extent, it seems that higher levels of silver nanoparticles cause stress in seeds and therefore decrease the seed germination and growth of seedlings. By decreasing reactive oxygen species, Ascorbate improves the germination and by increasing plasma membrane efficiency, CaCl2 enhances the seedling growth under drought stress.

Highlights:

  1. Silver nanoparticles increased the effect of stress on the seedlings of rice cultivars.
  2. Ascorbate and calcium chloride improved the germination and seedlings growth of the rice cultivars, respectively under drought stress conditions.

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.


Effect of Artemisia sieberi Extract Allelopathy on Emergence Characteristics and Nutrients Uptake of Prosopis cineraria
Asma Ricki Maryshany, Mahdieh Ebrahimi, Ebrahim Shirmohammadi,
Volume 5, Issue 1 (9-2018)
Abstract
Extended abstract
Introduction: Allelopathic effects of plant on one another are one of the most important concerns in reclamation and rehabilitation of rangelands in Iran. Allelopathy refers to the deterrent effects of a plant on growth, development or emergence of another plant. One of the rangeland reclamation methods is planting suitable and compatible species. However, without considering the plant’s allelopathis characteristic, it is highly likely that the project will be a failure. The present study sought to investigate the effects of Artemisia sieberi extract on seedling emergence, some morphological characteristics and nutrient uptake of Prosopis cineraria which has hard emergence.
Materials and Methods: The present study was carried out under greenhouse conditions, with 23±5 °C, 60% relative humidity and 70% water-holding capacity of soil. The experimental design was a completely randomized one with four replications. Soil samples were selected from Deging village, located in the city of Khash (Sistan and Baloochestan Province). In order to prepare the plant extract, the A. sieberi samples were dried in the shade and were ground to powder. Then, 190 g of the powder was put in a plastic bottle, then filled with 1 L ethanol and placed on a shaker for 24 hours. The resulting solution was filtered out and the extract was obtained. The planting was carried out in plastic pots with the capacity of 6 kg which were filled with 3 kg of soil. In each pot, 30 seeds were buried, at a depth of 3 cm. The treatments were treated at concentrations of 0.2% (2 ml in 1000 ml distilled water), 0.4%, and zero along with plant irrigation. The parameters measured included emergence percentage and rate, radicle and pedicel length, seedling dry weight, photosynthetic pigments, carotenoid contents and nutrient uptake of P. cineraria.
Results: The results showed that A. sieberi extract significantly decreased plant photosynthetic pigments. The highest chlorophyll a, b, total chlorophyll and carotenoid belonged to the control treatment and by increasing extract concentration, photosynthetic pigments decreased. In addition, the findings were that the highest and lowest nitrogen and phosphorus contents were obtained in the 0.2 and 0.4% treatments, respectively. Potassium and manganese decreased with increases in extract concentration. However, with increases in extract concentration, zinc significantly increased in the plant tissues. In general, the results showed that A. sieberi extract increases P. cineraria emergence in the 0.2% treatment.
Conclusion: In general, morphological traits and photosynthetic pigments of P. cineraria decreased with increases in the concentrations of A. sieberi extract. Artemisia extract had a different effect on the absorption of nutrients by P. cineraria. at low concentrations. It increased nitrogen and phosphorus adsorption and increased concentrations of manganese in high concentrations. The concentration of 0.2% of Artemisia extract had a positive effect on plant emergence. Given the positive effect of A. sieberi on the emergence of P. cineraria, plant extract at low concentrations can be used to increase emergence of P. cineraria, especially given that the P. cineraria has an emergence problem. However, due to the negative effect of A. sieberi on growth and absorption of nutrients in P. cineraria, the cultivation of these two plants is not recommended in dry rangelands.
 
 
Highlights:
  1. The extract of A. sieberi had deterrent effects on seed emergence and morphological characteristics of P. cineraria.
  2. Increasing the concentration of the A. sieberi extract led to a decrease in the morphological characteristics of P. cineraria.
  3. A. sieberi extract had negative effects on photosynthesis pigments of P. cineraria.


Response of Soybean (Williams cv.) Seed Germination to Aqueous Extract of Cocklebur (Xanthium spp.) and Common Lambsquarters (Chenopodium album)
Adel Modhej, Rozbeh Farhoudi, Sanaz Edalat,
Volume 5, Issue 1 (9-2018)
Abstract
Extended abstract
Introduction: Interference caused through weeds’ and crops’ competition for environmental resources and allelopathy brings about damage in crop species. Allelopathy is defined as a direct or indirect inhibiting or provoking effect of a plant on other plants through the production of chemical compounds introduced into the environment. Although the allelopathic effects of the shoot extracts of Xanthium spp and Chenopodium album on the germination of some crops have already been investigated, very few studies have so far been conducted to evaluate their adverse effects on soybean seedling growth. The aim of this study was to investigate the effect of different concentrations of aqueous extract of cocklebur and lambsquarters on germination and soybean seedling growth indices under Petri and Pot conditions.
Materials and Methods: In order to study the allelopathic effects of Cocklebur and Common lambsquarters on germination and seedling growth of soybean, two separate experiments were conducted under petri and pot conditions. In this experiment, the effects of aqueous extract concentrations (25, 50, 75 and 100%) of cocklebur and common lambsquarters were evaluated on seed germination of soybean in a completely randomized design with three replications. In each pot, five soybean seeds were planted with a depth of 2 cm. The extracts were added to the pots for 2 weeks after emergence.
Results: Allelopathic effect of common lambsquarters extract concentrations was higher than that of cocklebur in both experiments. Germination percentage (GP) reduction under 25, 50, 75 and 100% concentrations of common lambsquarters was 57, 84, 96.7 and 100%, respectively. GP reduction under the same concentrations of cocklebur was 17, 20, 34 and 54%, respectively. In the pot culture conditions, the root dry weight of soybean decreased with increases in extract concentration, so that the highest root dry weight belonged to the control treatment with 64 mg and the lowest values belonged to the effect of aqueous extract of weed with a concentration of 100%. The results on the EWRC scale showed that the soybean leaflet damages increased as the extract concentrations increased. The highest leaf damages were obtained in 75 and 100% of cocklebur and Chenopodium concentrations. The negative impacts of common lambsquarters were higher than those of cocklebur.
Conclusion: In general, the results of this study showed that the effects of different concentrations of the lambsquarters extract on germination and soybean growth of the Williams cultivar were higher under both Petri and pot conditions. The percentage of germination in the concentrations of 25, 50, 75 and 100% of the aqueous extract of cocklebur was 17%, 20%, 34% and 54%, respectively, and in lambsquarters, it decreased by 57%, 84%, 96% and 100%, respectively, compared to the control. On the other hand, spraying the extracts of lambsquarters and cocklebur caused necrosis and drying of soybean leaves. According to the results, in the absence of effective control of weeds, especially lambsquarters, in soybean farms, the damage caused by allelopathic elements will lead to a significant reduction in germination and seedling growth.
 
 
Highlights:
  1. In this study, the allelopathic effect of two important soybean weeds on germination and seedling growth of this crop were compared, which had been under-researched.
  2. Seed germination reaction and seedling growth were evaluated for the extract of aerial parts in two seed culture conditions of petri dish and potted seedlings.

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.

Evaluation of Allelopathic Effect of Euphorbia maculata Weed on Traits of Germination, Chlorophyll and Carotenoids Pigments of Wheat Cultivars
Ebrahim Gholamalipour Alamdari, Behroz Seifolahi, Zeinab Avarseji, Abbass Biabavi,
Volume 5, Issue 1 (9-2018)
Abstract
Extended abstract
Introduction: Generally speaking, plants contain various organic compounds which could influence the behavior of plant communities. These compounds are basically secondary metabolites which are found in various parts of plants such as rhizomes, roots, stems, leaves, flowers, fruits and seeds. The objective of the present study was to investigate the hetrotoxicity potential of different organs of Euphorbia maculata weed on traits of germination, chlorophyll and carotenoids pigments of wheat cultivars.
Material and Methods:  In this experiment Euphorbia maculate weed was collected at full maturity stage from the Moghan region, located in Ardebil Province. Then various organs of Euphorbia maculate such as stems, leaves, and fruits were separated from each other. Another treatment namely, a mixture of different organs, was also made. This experiment was carried out as a factorial, adopting a completely randomized design with three replications in Weeds Science Laboratory of Gonbad–e- Kavous University in 2017. The first factor was wheat cultivar at two levels, consisting of Morvarid and Gonbad and organs in 5 levels (control, stem, leaf, fruit and their mixture, with equal amount of each) were the second factor. For the bioassay experiment, from each organ and their mixture, 5% suspension (w/v) was prepared, using distilled water. 10 ml of concentrated extract of each organ was applied on 50 sterilized seeds of cultivars of interest in a petri dish containing filter paper. After 7 days, traits such as rate and percentage of germination, radical length, shoot length, seed length vigor index, chlorophyll a, b and total content and carotenoids content were measured.
Results:  The results showed that unlike the Morvarid cultivar, germination rate and germination percentage of the Gonbad cultivar significantly decreased, using aqueous extract of various organs of Euphorbia maculata and their mixture. The results also showed that the inhibition effect of fruit and leaf organs on the rate and germination percentage of the Gonbad cultivar were higher than that of other organs and their mixture. According to the results, stem, leaf and fruit extracts had a higher toxic effect on the radical length, compared with the shoot length of the Gonbad cultivar. The results of mean comparison also showed that seed length vigor index of the Morvarid and Gonbad cultivars decreased, due to hetrotoxic compounds of all organs of Euphorbia maculate. In terms of this trait, the highest significant decrease was found in the Gonbad cultivar, which was about 84.13%, compared with the control. In this study, the decreases in the photosynthesis pigments of total chlorophyll and carotenoids in both cultivars with aqueous extract of stem, leaf and fruit organs of Euphorbia maculata were different. The highest decrease of pigments was found in the fruit organ of the Morvarid cultivar. However, aqueous extract of mixed organs had a significant decrease and increase on the content of these pigments in the Morvarid and the Gonbad cultivars, respectively, as compared with the control. This may be due to differences in the quantity and quality of some allelochemicals as well as different reactions of the cultivars.
Conclusions:  Given the evidence of the hetrotoxicity potential of various organs of Euphorbia maculata weed on traits of germination as well as the chlorophyll and carotenoids content of wheat cultivars, it is advisable to exploit huge biomass generated by these luxuriantly growing weeds as bio-compounds in sustainable agriculture.
 
 
Highlights:
1- Study of allelopathic effect of Euphorbia maculate on various wheat cultivars in farms of the Moghan plain.
2- Aqeous extract of Euphorbia maculate organs significantly reduces germination as well as seedling growth of the Gonbad cultivar.
Effect of Chitosan Nano Particle and Potassium Nitrate on Germination and Some Morpho-physiological Characteristics of Seedlings of Quinoa (Chenopodium quinoa)
Ali Mansouri, Heshmat Omidi,
Volume 5, Issue 1 (9-2018)
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.

Effects of Foliar Application of Salicylic Acid and Spermine on Maternal Plant under Drought Stress on Germination Indices of Purple Coneflower (Echinacea purpurea)
Hakimeh Darvizheh, Mortez Zahedi, Bohlul Abbaszadeh, Jamshid Razmjoo,
Volume 5, Issue 1 (9-2018)
Abstract


Extended abstract
Introduction: Echinacea purpurea, a member of Asteraceae family, is a herbal medicine which is effective for promoting human immune system. Enviromental stresses including water defecit, which limit maternal plant growth, can also affect their seed quality and germination. Various compounds such as salicylic acid and spermin are known to be useful in the alleviation of harmful effects of drought on plants and their seed production.
Materials and Methods: In order to investigate the seed vigor of Purple Coneflower after foliar  application of salicylic acid (SA) and spermine (SPM) on maternal plant (no spray,75 mg/l SA, 150 mg/L SA, 75 mg/L SPM, 75 mg/l SA+75 mg/L SPM and 150 mg/L SA+75 mg/L SPM) under three irrigation regimes (irrigation after 20, 40 and 60% depletion of soil available water), a split plot experiment was conducted based on a completely randomized block design with three replications during 2016- 2017 growing seasons at research field of Institute of Forests and Rangelands, Iran.
Results: Water stress decreased the percentage and rate of germination, shoot and seedling length, shoot dry weight, germination energy and seed germination vigour. The results showed that foliar application had a significant effect on shoot, root and seedling length, shoot, root and seedling dry weight, germination rate, allometric factor, and germination vigour. The interaction effect of drought stress and foliar application indicated that non-stress and 150 SA+70 SPM mg/L had the highest radicle length (28.8 mm), radicle dry weight (1.81mg), seedling dry weight (6.20 mg) and Allometric factor (0.412).
Conclusions: Based on the results of the current experiment, the foliar application of salicylic acid and spermine improved the seed germination of coneflower plants under both normal and water stress conditions and the highest values of these parameters were obtained under combained application of high concentrations of salicylic acid (150 mg/L) and spermine (75 mg/L).
 
 
Highlights:
1- Investigating the foliar application of salicylic acid and spermine in maternal Echinacea purpurea plant under drought stress in germination of seed.
2- The foliar application of salicylic acid and spermine on maternal plants of Echinacea improved germination quality under water stress.
Effect of Magnetic Field on Seed Germination of Guizotia abyssinica under Drought Stress Conditions
Samaneh Hosseini, Mohammad Rafieolhossaini, Parto Roshandel,
Volume 5, Issue 1 (9-2018)
Abstract
Extended abstract
Introduction: Niger with the scientific name of Guizotia abyssinica (L.F.) Cass. belongs to the Asteraceae family. Niger seed contains 50-75 percentage of oil which is used in the treatment of rheumatism and burns, and as a substitute for olive oil. Its meal is also used for animal feeding. Environmental crises sustained by living systems are considered as stress. Drought stress is one of the non-biological stresses. Yield reduction due to this type of stress is reported to be higher than that related to other stresses. Since plant development starts from germination and for survival, the seeds should germinate to adapt themselves to the environmental conditions and establish themselves in the soil, the success of passing the germination stage will play an important role in other stages of plant establishment. Different studies have shown the positive effect of magnetic field on increasing germination characteristics. In this regard, applying a magnetic field before planting is a safe and inexpensive method for increasing germination and seedling growth. Seed priming is useful for a faster and more powerful response to drought stress and among different types of priming, physical priming is of particular importance for ecological reasons and for not having a negative impact on the environment.
Materials and Methods: In order to study the effect of seed physical pre-treatment and drought stress on seed germination characteristics of Niger, an experiment was conducted as factorial in a completely randomized design with three replications at the Research Laboratory of Seed Science and Technology at Shahrekord University. Different magnetic field intensities at five levels including (0, 50, 100, 150 and 200 mT (at 5 minutes period)) as the first factor and drought stress at five levels (0, -4, -5, -6 and -7 bar Polyethylene Glycol6000) as the second factor were considered.
Results: The results of variance analysis showed that the effect of drought stress, magnetic field intensity and their interaction were significant on all of the evaluated characteristics. The maximum germination percentage and rate and the minimum of T10 and T50 were observed in 50 mT field intensity under normal conditions. The minimum germination index under normal conditions and the maximum length and shoot dry weight under non-treatment conditions and the maximum root and shoot fresh weight in 200 mT field intensity under normal conditions were obtained. The maximum root length and dry weight were observed in 50 and 100 mT field intensity under normal conditions, respectively. 
Conclusions: Seeds which cross through a magnetic field, become swollen and probably as a result, the activity of auxin hormone in these seeds increases. In addition, the respiration level also increases in them and they have higher levels of energy and activity, which results in faster and more uniform germination and the creation of stress-resistant plants. In this study, although by increasing drought stress intensity, negative effects were observed on germination characteristics, the magnetic field under these conditions improved some germination characteristics. In general, for the purpose of improving germination and alleviating drought stress conditions, for 0, -5 and -7 bar potentials, the field intensity of 50 mT and for -4 and -6 bar potentials, the field intensity of 150 mT are recommended.
 
Highlights:
  1. The effect of magnetic field on germination of multipurpose seed of Niger plant.
  2. The effect of drought stress on germination of multipurpose seed of Niger plant, given Iran’s being located in dry belt.
  3. The positive effect of magnetic field on germination of Niger seed to improve the negative effects of drought stress.

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.

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

Evaluation of Germination and Biochemical Changes of Two Wheat (Triticum aestivum) Cultivars Under Pb(NO3)2 Stress
Seyed Ali Tabatabaei, Omid Ansari,
Volume 5, Issue 2 (3-2019)
Abstract



Extended abstract
Introduction: Heavy metal pollution is one of the most serious environmental problems. These metals which accumulate in food chain bring about a lot of hazards to both humans and animals. Among heavy metals, lead is considered to be the most dangerous heavy metal in the environment. It contaminates the environment through the lead-acid battery industry, paint and gasoline additives, insecticides, chemical fertilizers, car exhaust pipes and soldering. The objective of this study was to investigate the effect of Pb(NO3)2 on germination characteristics and biochemical changes of two wheat cultivars (Chamran and Kohdasht cultivars).
Materials and Methods: The objective of this research was to evaluate germination and biochemical changes of two wheat cultivars under Pb(NO3)2 stress, using three-parameter sigmoid model. The experimental design adopted was factorial with a completely randomized design, as the base design, with 3 replications. The first factor was 2 wheat cultivars (Kohdasht and Chamran), and the second factor was 6 levels of Pb(NO3)2 (0, 0.25, 0.5, 0.75, 1 and 1.5 mg.L).
Results: The results showed that with increases in levels of Pb(NO3)2 stress, germination percentage, germination rate, normal seedling percentage, seedling length, seedling weight and seed vigor index reduced for both wheat cultivars. The results of fitting three-parameter sigmoidal to characteristics indicated that the highest characteristics and X50 were obtained from the Chamran cultivar. The highest germination percentage (96%), germination rate (23 seeds per day), normal seedling percentage (93.33%), seedling length (13.07 cm), seedling weight (0.07) and seedling vigor index (12.18) were obtained from the Chamran cultivar under non-stress conditions. Pb(NO3)2 stress increased proline and catalase activity but reduced protein, proline and protein for the Chamran cultivar, as compared with the Kohdasht cultivar.
Conclusion: Generally speaking, the results showed that Pb(NO3)2 had a significant effect on germination characteristics and catalase, proline and protein of wheat. Finally, it could be said that in copper-accumulated areas, choosing proper cultivars can slightly mitigate the damages caused by copper. The Chamran cultivar seems to be a better candidate for these conditions.
 
Highlights:

  1. Evaluation of the effect of Pb(NO3)2 stress on germination characteristics of wheat.
  2. Using three-parameter sigmoid model for the evaluation of biochemical changes and germination of wheat under Pb(NO3)2 stress.

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