نشریه پژوهش های بذر ایران
سال نهم شماره 1 (پیاپی 17، بهار و تابستان 1401)

Pulses are among the best sources of plant protein and important components of crop rotation, which in recent years, have been considered one of the major options for plant research. Seed storage is one of the important traits in legume breeding. Storage temperature, seed moisture content, and storage duration are the most important factors affecting seed quality during storage. Inappropriate storage conditions lead to deterioration and reduction of seed quality during storage, which is severely affected by the environmental conditions of storage.

This research was conducted at the Seed Technology Laboratory, Faculty of Agriculture, Yasouj University in 2014 as a three-way factorial based on the completely randomized design with 5 replications of 20 seeds. Seeds with moisture content at 5 levels (6, 10, 14, 18, and 22%) and storage temperature at 4 levels (15, 25, 35 and 45 °C) were stored for 9 months (0, 30, 60, 90, 120, 150, 180, 210, 240 and 270 days). After sampling at the end of each month, a standard seed germination test was done using the pleated paper method in a germinator at 25 °C for 10 days. Also, an electrical conductivity test of the electrolytes leaked from the seeds incubated for 24h in water at 20 ˚C was done with 4 replicates. Some germination attributes and electrical conductivity of the electrolytes leaked from the seeds were measured according to standard methods.

According to the results, interaction effects of storage temperature, seed moisture content, and storage duration on germination indices and electrical conductivity of bean seeds were significant (P<0.1). The germination trend during storage at 15 °C and seed moisture content of 6% decreased from 94% to 81% after 270 days of storage, so that germination decreased to 35% under similar moisture content after 270 days of storage as temperature increased from 15 to 45 °C. As the storage time passed, electrical conductivity increased and this increase was more pronounced at higher temperatures. Viability constants were calculated 9 months after storage using the seed viability equation, in which KE, CH, CW, and CQ were calculated -5.39697, 0.03201, 2.13041, and 0.000017, respectively.

The results showed that the electrical conductivity of the leaked material increased with increasing storage temperature and seed moisture content, which led to lower viability of seeds. At 15 °C and 6% seed moisture content provided better conditions for seed survival during the 9-month storage time compared with all other temperatures and moistures and had the lowest rate of deterioration. The results showed that with increasing seed temperature and moisture so that they had to lowest electrical conductivity of the leaked material from seeds and deterioration rate.

Guar (Cyamopsis tetragonoloba L.) is an annual, dicotyledonous plant of the legume family, also known as cluster beans. This plant can tolerate salinity and drought stress well. Optimal planting date and plant density are factors affecting the quality and quantity of crops. The distribution of plants in the field influences the absorption and productivity of environmental factors affecting the growth and intra- and inter- competition and eventually is one of the factors determining the quantity and quality of yield. Different planting dates set off different conditions in terms of temperature day length, relative humidity, solar radiation, ripening and harvest time and thus, affect the quantitative and qualitative characteristics of seeds. The purpose of this experiment is to evaluate the quality and also to evaluate some of the germination characteristics of Guar seeds at different dates and planting densities under the climatic conditions of Guilan.

This experiment was conducted in the spring and summer of 2017 in the research farm of Rasht Rice Research Institute located in Gil Pardehsar village at Sangar as a factorial based on a randomized complete block design with three replications. Experimental treatments included four planting dates (12 May, 26 May, 9 June and 23 June) and three plant densities (20, 40 and 60 plants. m-2). Seed harvesting was done as the pods in 75% of the plants in each plot turned brown and traits such as germination percentage, germination rate, root and shoot length and fresh and dry weight of roots and shoots, longitudinal index of seedling vigor, 1000- grain weight, electrical conductivity and alpha-amylase activity were investigated.

The results of the present study showed that guar seeds had the highest quality on 26 May and a density of 40 plants.m-2. Due to favorable climatic conditions during the period of seed filling, germination rate, germination percentage, seedling vigor index, root length and 1000- grain weight was high on 26 May. The amount of these traits decreased with delay in planting. The amount of electrical conductivity in 23 June date of planting treatment showed the highest value. The highest level of alpha-amylase activity was observed on 9 June.

In general, it can be concluded that the best planting date and plant density of guar seeds in Guilan province with the highest quality of seeds and germination is on 26 May and 40 plants.m-2.

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.

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.

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.

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.

St. John’s wort is one of the most amazing and medicinal plants of interest worldwide, which is nowadays known as a certain cure for depression. However, the presence of dormancy and low seed germination is a barrier to the progress of its breeding programs. Despite the richness of the plant’s genetic resources, there are only a few studies reported on its propagation and maintenance in Iran, most of which do not mention the geographical origin of the used seeds or explants. The current study was carried out aiming to evaluate in vitro plant propagation of eight Iranian endemic populations of St. John’s wort seeds which belonged to different geographical origins, emphasizing seed dormancy phenomena.

Following the collection of eight populations of St. John’s wort (Hypericum perforatum L.) seeds from different geographical regions of Iran, the Murashige and Skoog culture media (common salt mixture as a control, MS improved with gibberellic acid and a modified combination of MS) was used in an effort to investigate the effect of culture medium as well as seed collection locations on the germination percentage of these populations.

The results showed that the interaction between the seed collection locations and the culture medium on seed germination was significant at P<0.01. Besides, the effect of changing culture media on seed germination was significant in all populations at P<0.01, except for Meshkin-Shahr. In other words, the seeds collected from Meshkin-Shahr germinated easily as well as notably under in vitro conditions (97.3% on average), and there was no need either to modify the combination of MS medium or to use gibberellic acid for seed dormancy elimination. The seeds originated from Challus and Peresk had the lowest germination in the control medium (22.3%, on average). Seeds from Challus and Saqqez had better germination in the media enriched with gibberellic acid compared to the control and the modified MS media (88% and 65%, respectively). However, less than half of the Parvar seeds germinated in the MS medium improved with GA3, compared to the control. Cultivation of seeds obtained from Fereydunkenar in common MS medium also led to better germination than using GA3 and modifying the combination of medium with 95% and 99% confidence levels, respectively.

The results of the current study demonstrated that the observed difference in seed germination percentage is remarkable in the Iranian endemic St. John’s wort populations under in vitro conditions. Moreover, the variation among national populations was significant. Besides, the response of the seed populations originating from different locations varied with respect to the changes in the culture medium and in the different cases. This shows the considerable effect of the growth location of the maternal plant on the characteristics of the next generation seeds, especially the way they germinate. Hence, it is very important to pay attention to the seed’s origins in the studies and it is investigable.

Numerous studies are being carried out to reveal the effects of different treatments on the germination of seeds from various plants. The most commonly used method of analysis is the nonlinear regression which estimates germination parameters. Although the nonlinear regression has been performed based on different models, some serious problems in its structure and results motivated researchers to investigate alternative approaches with higher accuracy and precision. The main purpose of the present research is to introduce the alternative parametric time to event model and comparing its reliability to the nonlinear regression in experiments carried out under different conditions.

  The results of four different experiments were used here including the effect of Potassium cyanide on walnut seed germination, the effect of salinity on wheat seed germination, the effect of water potential on corn seed germination and the effect of temperature on cotton seed germination. The nonlinear regression and time to event methods were applied based on the Gompertz model. The obtained standard errors from the two models were further assessed using the Monte-Carlo method.

Both methods provided well-fitting models according to the MSE and R2   criteria. Although the germination parameters were approximately identical in both models, the standard error of parameters in nonlinear regression was significantly less than those of time to event method except for the experiments in which all tested seeds germinated within the time frame of study so that in the latter case the estimated standard errors in both models were identical. The Monte-Carlo method confirmed the results of the time to event model and reveals the underestimation of the nonlinear regression method in estimating the standard error of parameters.

Generally, the results of this research showed that the time to event model can be trustfully utilized in seed germination studies under different conditions and treatments. This model, not only provides precise estimates of the germination parameters but also provides the precise standard error of parameters that have important roles in making inferences for parameters. The drc package in R software enables researchers to fit the different time to event models.

Reports indicate the invasion of two species of Ivy-leaved morning-glory (Ipomoea hederaceae Jacq) and Asian spider flower (Cleome viscosa L.) to summer crops fields such as soybeans in Golestan province. Considering the importance of knowing the cardinal temperatures of germination in the models for predicting the presence of weeds and consequently designing correct management strategies on these plants, this experiment was conducted to study the germination behavior and to compare the cardinal temperatures of germination for two species of Ivy-leaved morning-glory and Asian spider flower under two conditions of constant and alternating temperatures.

In order to study the effects of constant and alternating temperature on the percent, rate and estimating cardinal temperature of germination for Ivy-leaved morning glory and Asian spider flower, two separate experiments as a Completely Randomized Design with four replications were carried out at the seed laboratory of Gorgan University of Agricultural Sciences and Natural Resources. Studied temperature treatments on Ivy-leaved morning glory included the constant temperatures of 10,15,17,20,25,30,35 and 40 oC and alternating temperatures of 12.5:7.5,10:15, 12.5:20, 15:25, 20:30, 25:37.5, 30:42.5 and 35:45 oC. Temperature treatments on Asian spider flower included the constant temperatures of 15, 20, 23, 25, 28, 30, 35, 40, 45 and 50 o C and alternating temperatures of 15:20, 20:25, 20:30, 25:30, 25:35, 30:40, 30:45, 30:50 and 40:50 oC.

Results indicated that alternating temperatures had a positive effect on the germination of Ivy-leaved morning glory, which increased from 78% at constant temperatures to 94% at alternative temperatures. However, the maximum germination percentage of Asian spiderflower at the alternative temperature of 20:30 was 79%, which had no significant difference with a constant temperature of 30 with 84% germination. The base temperature for seed germination of Ivy-leaved morning glory at alternating temperatures (10.09 oC) was a little lower than that of constant temperatures (11.25 oC). But in Asian spider flower, the base temperature at alternating temperatures (17.57 oC) was more than that of constant temperatures (15.43 o C).

The most important factor in the occurrence of such different responses to constant and alternating temperatures in Ivy-leaved morning glory and Asian spider flower is their adaptation to environmental conditions and their survival in highly degraded agricultural environments. These two weeds are warm-season plants and their seeds enter the soil seed bank in autumn. The presence of dormancy (regardless of its type) in the seeds of these two plants prevents the germination of their seeds in winter; and the experience of alternating temperatures at this time prepares the seeds for germination in the spring. The base temperature of Ivy-leaved morning glory was not much different under the constant and alternating temperature conditions. But the base temperature of Asian spider flower was higher under alternating temperatures compared with constant temperatures.

The germination stage ensures the durability, establishment, and final yield of plants.  The final density of plants per unit area is resulted when the planted seeds germinate fully and with adequate rate. Plants mainly undergo abiotic stresses that are a considerable constraint for agricultural production worldwide. Seed priming is one of the simplest and cheap methods to improve seed germination, acceleration of seedling growth and establishment, uniformity, reduction of flowering time, vigorous seedling production, etc which leads to improved quality and yield of crop under stressful and non-stressful conditions. This study aimed to investigate the effect of different types of priming on enzymatic and physiological changes of French bean seed under cobalt chloride stress conditions.

To examine the effect of priming on germination indices, the activity of antioxidant enzymes and proteins in French bean under cobalt chloride stress, a factorial experiment was performed in a completely randomized design with three replications. These factors included four levels: seed priming with 100 mg / l salicylic acid and mannitol, control and distilled water (no priming), and three levels of cobalt chloride stress (0, 100, and 200 mg / l).

The results showed that with increasing cobalt chloride concentration, germination indices (germination rate, root length, root fresh weight, stem fresh weight and stem dry weight) decreased. However, in the pretreatment of distilled water, salicylic acid, and mannitol there was a significant increase in germination indices (mean germination time, radicle length, plumule length, fresh radicle weight, and weight plumule) was observed. The interaction effect of priming and cobalt chloride caused an increase in radicle dry weight compared to control × stress treatment. The highest values of fresh radicle weight (14.4 g), dry weight of plumule (0.27 g), and plumule length (0.17 cm) were obtained in hydro priming pretreatment. The results also showed that hormone priming under stress conditions of 200 and 100 mg / l cobalt chloride increased protein content and polyphenol oxidase activity of French bean seedlings compared with the control treatment, respectively. Osmo priming increased the activity of catalase and peroxidase enzymes under stress and non-stress conditions resulted by 200 mg / l cobalt chloride.

according to the results of the present study, cobalt chloride reduced some physiological and biochemical traits of French bean seeds. However, the French bean has a relatively high cobalt chloride tolerance capacity, so that it showed good tolerance to different concentrations of cobalt chloride for up to 9 days.

Galbanum is one of the most important native medicinal plants in Iran, and nowadays the use of its products and derivatives has become widespread in various industries. Thus, the excessive harvest of this species within its natural habitats has increased. Therefore, the species is enlisted as prone to extinction. Due to the lack of information about germination behavior and dormancy alleviating or breaking methods of Galbanum seeds, less attention has been paid to this plant species by seed science researchers. Hence, this study was designed and performed to investigate the effects of different treatments on Galbanum seed dormancy-breaking.

In this study, two Galbanum seed populations were collected from Boyer-Ahmad pastures (Iran, Kohgiluyeh and Boyer-Ahmad Province) and Pakan Bazr Isfahan Company (Iran). Seeds were exposed to a cold stratification test for 120 days and germinability and dormancy breaking responses were studied. Also, seed drying effects on germinability after exposure to stratification treatment were investigated to evaluate the practical aspects of this treatment. The impacts of different hormonal pre-treatments including gibberellic acid (GA3) and cytokines (Kinetin, 6-Benzylaminopurine) at different concentrations on germination and dormancy behaviors were investigated so as to assess the effect of these treatments on seed dormancy breaking.

Results showed that germination/dormancy behaviors of Galbanum populations were different and also the effect of different treatments on seeds germination and dormancy varied. An increase in germination was observed when stratification was applied for up to 60 days on two seed populations, thereafter germination decreased by prolonged stratification. Also, it was revealed that desiccation of the treated seeds after stratification reduced seed germination. Examining the cause of this issue revealed that the most important reason for the decrease in seed germination in long periods of stratification was the germination of seeds in the stratification bed and in other words, the difference in seed dormancy levels in different stratification periods. Seed germination behavior and dormancy breaking were improved significantly in both Galbanum populations when the different concentration of gibberellic acid and cytokinins was used.

The results of this study indicated the existence of different levels of seed dormancy in different Galbanum populations. It was also found that cold stratification and hormonal pre-treatment of seeds can be significantly effective in seed dormancy breaking. Eventually, it was concluded that Galbanum seed dormancy was classified as semi-deep and deep morphological dormancy due to the effects of different treatments.

Structural and physiological delicacy of soybean seeds is known as an important quality indicator in the cultivation of this plant, but at the same time, the most chronic problems of soybean seed quality are the reduction of seed quality during storage and before sowing. The effect of some nutrients on the quality of soybean seeds under accelerated aging stress was investigated

Experiments were conducted for two consecutive years (2019-2020) in the research field of Lorestan University, Faculty of Agriculture in a randomized complete block design. Nutritional treatments included nitrogen and phosphorus application (as soil application) and iron and molybdenum as foliar application. Seeds were harvested at the maturity stage and 1000-grain weight and seed coat resistance to mechanical damage was investigated. Following the exposure of seeds to accelerated aging, leakage from seeds and germination were measured.

The results showed that nutrition had a significant effect on all studied traits. However, the effect of year was only significant on 1000-seed weight and resistance to mechanical damage of seed coat. The highest number of traits related to seed quality was related to complete fertilizer treatment (N-P-Fe-Mo) and accelerated aging had a less negative effect on them.

Among the nutrients, nitrogen and phosphorus had the most effect on germination indices, and iron and molybdenum were in the next ranks. Seeds with strong vigor and treated with fertilizer were less affected by accelerated aging and had better germination. The lower the seed vigor, the more sensitive they were to this stress.

Lavandula angustifolia L. is one of the most important plants belonging to Lamiaceae which has abundant use in traditional and pharmacological medicine. Lavender seed dormancy is one of the problems in producing seedlings which increases seed consumption. In this regard, an experiment was carried out to investigate different treatments for seed dormancy elimination of Lavender and measuring germination and growth indices.

An experiment was conducted in a completely randomized design with three replications at the Ecophysiology Laboratory of Karaj Institute of Medicinal Plants in 2018. The experiment consisted of 14 treatments on seed dormancy elimination. The treatments included the control, hormonal treatments (Gibberellic acid with 250, 500, 750 and 1000 mg/l concentrations) and Prechilling treatments (7, 14 and 21 days of refrigeration). The integrated treatments were 7 days refrigeration + 500 mg/l gibberellic acid, 14 days refrigeration + 500 mg/l gibberellic acid, 7 days refrigeration + 1000 mg/l gibberellic acid, 14 days refrigeration + 1000 mg/l gibberellic acid, 30 minutes at 40 ° C water + 14 days refrigeration, and 30 minutes at water 40 degrees +14 days refrigeration + 500 mg/l gibberellic acid.

The results showed that the highest germination percentage (70.67%), germination rate (24.26%) and germination index (246) were achieved in 750 mg/l Gibberellic acid, and the highest epicotyl length (5.09 cm), seedling length (6.23 cm) and seedling fresh weight (0.57 gr) were produced with 500 mg/l Gibberellic acid. Also, the lowest mean germination time (MGT) (4.12s day) was obtained in 1000 mg/l Gibberellic acid treatment. Also, 7 days of refrigeration + gibberellic acid at 500 mg/l treatment had no significant difference with the other concentrations of gibberellin treatments. Therefore, low gibberellin concentration with 7 days of prechilling had the same effect as higher gibberellic acid concentrations. In addition, 14 days of refrigeration + 1000 mg/l gibberellic acid treatment and treatment of 30 min in water at 40 ° C +14 days prechilling + 500 mg/l gibberellic acid produced the lowest shoot (0.78, 0.82 cm), seedling height (0.99, 1.04 cm) and fresh weight (0.013, 0.01 gr) that showed the negative effects of increased prechilling time and water at 40 ° C,

It was finally found that the lavender seed dormancy type is physiologically non-deep and moderate and Gibberellic acid is a suitable substitute for prechilling. The best treatment was gibberellic acid with a concentration of 750 mg/l to break the dormancy of lavender seeds.

Iranian oak has the largest forest habitat in the country and has a high position in terms of economy and protection. Recent studies have confirmed the positive effects of carbon nanotubes on the germination and organ growth of herbaceous and woody species. Nanotechnology is an evolving field in all periods of human life and various research is done to use nanomaterials in different fields. Nanotechnology can provide a good medium for the production of plants with suitable characteristics or provide better growth conditions for plants. The aim of this study was to investigate the effect of carbon nanotube treatments, calcium chloride 1% and potassium nitrate 1% on the germination traits of Iranian oak seed (Quercus brantii Lindl).

Treatments included carbon nanotubes at five levels (concentrations of 10, 25, 50, 75, and 100 mg/l) for six hours, 1% calcium chloride for 48 hours, potassium nitrate for hours 24 hours and control treatment, which were primed without using any materials and germination traits were tested on them.

According to the results, carbon nanotubes affected germination traits, so that Iranian oak seeds at a concentration of 75 mg/l had the highest germination percentage and rate, and primed seeds with a concentration of 100 mg/l had the highest mean germination time. The lowest germination percentage, speed and mean germination time were related to control seeds.

The results showed that carbon nanotubes with 75 mg/l had the most positive effect on germination traits. Therefore, from an economic point of view, the use of this concentration is recommended for priming oak seeds.

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.

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.

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.

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.