جستجوی مقالات مرتبط با کلیدواژه « پیری تسریع شده » در نشریات گروه « زراعت »

Background and objectivesSoybean is considered one of the most important oil and protein plants in Iran and the world. Considering the importance of soybean yield and identifying traits effective in increasing it, this research was conducted with the aim of investigating the relationship between seed yield and agronomic and physiological traits of soybean and determining the traits that have a greater effect on seed yield under normal and accelerated aging conditions.Materials and methodsThe present experiment was conducted in the research farm of the Faculty of Agriculture of Shahrood University of Technology during 2017-2018 and 2019-2020, in a factorial experiment in the form of randomized complete blocks in three replications on Katol variety. The treatments included accelerated aging in two levels (normal seeds and aged seeds) and seaweed extract in three levels (control, pre-treatment and foliar spraying). The seeds used were obtained from the research center for agriculture and natural resources of Mazandaran and the seeds were harvested in the same year and until the time of testing, they were kept in a controlled warehouse with a cooling system at a temperature range of 14 to 17°C and a relative humidity of 30 to 40%. In order to apply aging, the seeds were placed for 72 hours at a temperature of 41°C and a relative humidity of 95%.ResultsThe results showed that in plants obtained from normal seeds, 84.81% of the changes in seed yield are justified by the number of pod per plant, the number of seed per pod and the 100 seed weight. In these plants, the 100 seed weight and then the number of pods per plant had the most direct and positive effect. The most direct and positive effect was attributed to the 100 seed weight, followed by the number of pods per plant. The trait of the number of seed per pod affected the seed yield both directly and indirectly through the effect on the 100 seed weight. Causality analysis in the plants obtained from aged seeds showed that the characteristics of final emergence percentage, membrane stability index, leaf area index, anthocyanin, hydrogen peroxide, superoxide radical, number of pods per plant and 100 seed weight were entered into the model as main variables and 91.33% of the changes are explained by these eight traits. Seed pre-treatment with seaweed extract increased seed yield by increasing the percentage of final emergence of the field, the 100 seed weight and the amount of glutathione in the leaves of the plant. Foliar spraying of seaweed extract caused a significant increase in seed yield through increasing the weight of 100 seed weight and membrane stability index.Conclusion The characteristics of 100 seed weight and number of pods per plant in plants obtained from normal and aged soybean seeds can be considered as selection criteria for improving and improving yield due to their direct and increasing effect on seed yield.

Due to the high sensitivity of seeds to damage caused by diseases or environmental stresses, germination is considered an important stage in the plant life cycle: Germination, its uniformity and emergence decline during storage due to seed vigor deterioration. Moisture stress is one of the important environmental factors affecting germination, especially during improper storage. Seed priming with gibberellic acid improves seedling characteristics in different plants under different environmental conditions. Therefore, this research aims to investigate the effect of gibberellic acid and seed deterioration on germination indices and antioxidant enzymes of safflower seeds (Carthamus tinctorius L.) under water stress conditions.

In order to investigate the effect of gibberellic acid on germination indicators and changes in antioxidant enzymes of aged safflower seeds under osmotic stress conditions, a factorial experiment was conducted in the form of a completely randomized design with four replications. The first factor includes three osmotic stress levels: zero (control), -0.4, and -0.8 MPa, the second factor includes nine aging levels (zero, 1, 2, 3, 4, 5, 6, 7, and 8 days of aging). at a temperature of 41 degrees Celsius) and the third factor included seed priming treatment at three control levels (non-priming), zero (hydro-priming), and priming with 50 mg/l gibberellic acid. A 3-parametric sigmoid model was used to show the changes in germination indices at different levels of seed deterioration.

The effect of osmotic stress, seed deterioration, and seed priming on the measured indices such as germination percentage, germination rate, seedling dry weight, normal seedling percentage, seedling length, seed germ, catalase, and ascorbate peroxidase, as well as seed protein were significant so that the measured indicators decreased with increasing seed deterioration and moisture stress. The results showed that the highest measured germination indices were obtained from seed treatment with 50 mg/l gibberellic acid under normal osmosis and non-deterioration conditions. Also, seed priming with gibberellic acid treatment caused an increase in catalase, ascorbate peroxidase, and protein activity compared to non-primed seeds under deterioration and non-deterioration conditions.

Results showed that the most suitable prime level used was gibberellic acid 50 mg/l, which had acceptable results under both stress conditions and normal conditions and deterioration and non-deterioration in comparison with other treatments. Therefore, the use of gibberellic acid hormone can help to improve germination indices as a result of changes in biochemical activities.

Highlights:
1. The effect of accelerated aging and priming on safflower seed germination under moisture stress conditions was investigated.
2.The effect of priming on catalase and peroxidase activity of aged safflower seeds was investigated.

Ellagic acid is a natural polyphenol compound, and different concentrations and ways of using it cause different reactions in plants. This research was conducted to investigate the effect of ellagic acid and seed quality on the phenological stages and yield of soybeans.

The factorial experiment was designed and implemented in a randomized complete block design in three replications in the agricultural years of 2019 and 2020 in the research farm of the Faculty of Agriculture, Shahrood University of Technology. In this experiment, the initial quality of the seed was considered in two levels (normal seed and aged seed) and ellagic acid in four levels (zero, priming, foliar spraying and combined application of priming and foliar spraying with a concentration of 50 mg/liter). Accelerated aging test was used to apply aging and for this purpose, the seeds were kept for 72 hours at a temperature of 41°C and a relative humidity of 95%. Seed priming was done with a concentration of 50 mg/liter of ellagic acid, following the principles of seed aeration for six hours. The spraying treatment was done early in the morning and at the beginning of flowering (R1) and in favorable environmental conditions.

The results showed that accelerated aging in the first and second year of the experiment, respectively, caused a decrease in the final emergence percentage of seedling in the field by 30.93 and 29.93% compared to the control. In the first and second year, the normal seed priming test with ellagic acid increased the final emergence percentage of field by 16.33 and 12.67 percent, respectively. The final emergence percentage of the field in the first and second year of the experiment in aged seeds that were primed with ellagic acid was improved by 14.33 and 8.33%, respectively, compared to the control. Accelerated aging caused a significant decrease in germination rate by 37.66% compared to the control. The final emergemce percentage of seeds that were primed with ellagic acid increased by 18.75% compared to the non-application of this substance. In this experiment, accelerated aging caused a delay in the occurrence of phenological traits in soybean plants. The use of ellagic acid as priming and the combined use of priming and spraying could increase the rate of occurrence of phenological traits to a significant level. Applying accelerated aging in the first and second year of the experiment caused a decrease of 25.85 and 28.78 percent of seed yield, respectively. The use of ellagic acid in the form of priming, foliar spraying and the combined use of priming and foliar spraying increased the seed yield by 23.59, 23.23 and 55.48%, respectively, compared to the control.

The use of ellagic acid as priming and the combination of priming and spraying can be suggested to accelerate the occurrence of phenological traits in soybeans. In this study, the application of ellagic acid as priming worked better than foliar spraying. It is recommended to use priming and ellagic acid solution to improve soybean yield under normal and aging conditions.

Soybean seeds are sensitive to storage due to their high oil content and they aged quickly. Aging of seeds leads to a decrease in the percentage and speed of germination and ultimately to a decrease in seed yield. Although the aging rate can be reduced with proper storage methods, the application of some treatments on the aged seeds or spraying some substances on the plants obtained from these seeds can be effective in improving the seed yield. The use of anti-aging substances such as seaweed extract in plants can act as antioxidants and reduce the effects of aging.
 
In order to evaluate the phenological stages and yield of soybean, an experiment was carried out in the research farm of Shahrood University of Technology during 2019 and 2020 in three replications. The treatments include the initial seed quality in two levels (normal seeds and aged seeds) and seaweed extract (Ascophyllum nodosum) in four levels (control, priming, foliar spraying and combined application of priming and foliar spraying with a concentration of 0.3%). The experiment was carried out as a factorial in the form of a basic design of randomized complete blocks.
In this research, applying accelerated aging caused a significant increase in phenological traits in soybean plants. The use of seaweed extract as a priming and the combined use of priming and foliar spraying could increase the rate of occurrence of phenological traits to a significant level. The seed yield in plants obtained from aged seeds was 32.69% less than that of control plants. The use of seaweed extract as priming, foliar spraying and the combined use of priming and foliar spraying increase the seed yield by 43.54, 15.69 and 87.85 percent, respectively. Aging caused a significant decrease of 23.50 and 25.33 percent of final emergence percentage. Pretreatment of normal and aged seeds with seaweed extract in the first year increased this trait by 16.33 and 7.33% compared to the absence of seaweed extract. In the second year of the experiment, the application of seaweed extract resulted in a 12.67% increase in seedling growth under normal conditions, and an 8.33% increase was recorded with the application of seaweed extract under aging conditions.
 
In this study, the application of seaweed extract as seed priming better than foliar spraying. It is possible to recommend priming and the combination of priming and foliar spraying with seaweed extract to accelerate the occurrence of phenological traits in soybeans. The combined use of priming and foliar spraying of seaweed extract is recommended to improve the performance of soybeans in normal and aged conditions.

In order to evaluation of some related to seed germination and seedling vigor traits of six mono germ sugar beet cultivars by accelerated ageing test, a research was conducted as factorial 4×6 (6 cultivars and 4 seed size) by 4 replications based on completely randomized design in seed quality analysis laboratory of Seed and Plant Certification and Registration Institute (SPCRI) at Karaj during 2019. Experiment treatments were including, Toucan, Dorotea, Rasta, Sharif (006), Pars (005) and Torbat (004) cultivars and seed width sizes, including 2, 3, 3.25 and 3.5 mm. By standard germination test conducting, after seeds accelerated ageing, final germination and normal seedlings percent, germination rate, germination meantime, coefficient of germination uniformity, seedling dry weight and length and seedling weight and length vigour indices determined. Results revealed that cultivar× seed size interaction effect was significant for all measured traits. The most final germination and normal seedlings percent and belonged to Sharifcultivar3.5 mm size seeds. AlsoTorbatcultivar3.5 mm size seeds had the most germination rate and the lowest mean germination time. Sharif cultivar 2 and 3 mm size seeds had highest coefficient of germination uniformity. The highest seedling dry weight belonged to Rasta and Doreata cultivars 3.5 size seeds. Rasta cultivar 3.5 mm size also had the most seedling length. Pars, Rasta and Toucan cultivars 3.5 mm size seeds had the most seedling weight vigour index and the most seedling length vigour index investigated in 3.5 and 3.2 mm size seeds of Torbat cultivar 3.5 mm size seeds. Generally, Sharif cultivar and 3.5 mm size seeds had more germinability and strong vigour.

Seed deterioration is associated with oxidative stress and uncontrolled accumulation of reactive oxygen species. Seeds have a group of enzymatic and non-enzymatic antioxidants that protect them against reactive oxygen species and help maintain seed vigor and support seed germination processes. The response of different cultivars to seed deterioration is different. Knowledge about the sources and mechanisms of deterioration and how different cultivars respond can help to select the appropriate cultivar for the region and also provide useful information in selecting and applying appropriate management methods for storage and increasing the storage time of seeds.

The Experiment was conducted as factorial based on a completely randomized block design with three replications. Treatments included one and six months of natural storage (4˚C, 11 percent moisture content of seeds and 60% RH) and accelerated aging (96 hours at 45˚C and 100% RH) applied on four cultivars including Hashemi, Gilaneh, Khazar and Domsiyah. Germination percentage, germination rate, shoot length, radicle length, shoot dry weight, radicle dry weight, shoot vigor index (SVI), α-amylase activity, catalase (CAT), peroxidase (POX), superoxide dismutase (SOD) activity, malondialdehyde (MDA) and hydrogen peroxide (H2O2) content were evaluated.

The results showed that accelerated ageing and storage of seeds for six months led to reduced germination percentage, germination rate, shoot length, radicle length, shoot dry weight, radicle dry weight, shoot vigor index (SVI), α-amylase activity reduced in all four cultivars. This decrease was accompanied by an increase in the free radical content of MDA and H2O2 and a decrease in the activity of the antioxidant enzymes SOD and POX. Malondialdehyde content was lower in the seeds stored for six months. The activity of CAT increased after deterioration treatment, this increase was more intense in the seeds stored for six months. These seeds also showed lower H2O2 content compared to accelerated aging seeds. Khazar cultivar showed lower H2O2 content as a result of higher CAT enzyme activity. Moreover, this cultivar showed better germination percentage and germination rate after deterioration treatment compared to other cultivars. The decrease in germination percentage due to deterioration in Domsiyah was very severe. This cultivar showed the lowest germination percentage, germination rate, seed vigor and α-amylase activity in the accelerated aging treatment. Gilaneh and Hashemi cultivars showed higher germinability, α-amylase activity and SOD and POX at the beginning of the experiment, but after deterioration treatment, their germinability decreased along with the activity of antioxidant enzymes.

In all studied cultivars, the accelerated aging and storage of seeds for six months adversely affected germination rate. This decrease was accompanied by an increase in free radicals in the seeds and a decrease in the activity of antioxidant enzymes SOD and POX, which were less severe in Khazar cultivar and more severe in Domsiyah cultivar. These results indicate the greater importance of the storage conditions in Domsiyah cultivar.

Abstract Deterioration of seeds is one of the important factors in reducing seeds vigor and limit germination. In order to investigate the effect of gibberellic acid hormone on recovery of seeds, and seedling growth in Varamin cotton seed. The experiment was done randomly three times. The experimental sets consisted of two decline levels (48 and 96 hours) with witness and 2 dense levels of gibberellic acid hormone (500 and 1000 PPM) with witness, and the treatment of gibberellic acid hormone was completed in 3 styles (before deterioration, after deterioration and before and after the deterioration. The results showed that the combination of treatments at 500 PPM without deterioration indicated that plumule length, root length, dry root weight, the amount of seed reserves, efficient use of reservoir seed, seed fraction of the resources consumedhad the best treatment. In the prime applying experiment before deterioration, in 500 PPM density with rate and uniformity of germination, D10, D90, plumlule length, root length, dry root weight, dry plumule weight, usage amount of reserves, effective use of resources, consumption and seed fraction, had the bestresult; and at 1000 PPM level the percentage of germination, demonstrated the highest improvement. Finally, in general we can say that gibberellic acid can recover deteriorated seeds.

Decreased vegetative growth is one of the consequences of seed decay that may reduce plant yield. In order to investigate the effect of seed decay on germination and seedling growth of wheat cultivars in laboratory conditions, an experiment was conducted in a completely randomized design with three replications in 2010 in the laboratory of the Faculty of Agriculture, Islamic Azad University, Gorgan Branch. The treatments studied in this test included three levels of burnout (control, 72 and 96 hours). They were incubated for 45 and 96 hours at 45 ° C and 100% relative humidity to induce deterioration. The results showed that germination percentage and germination rate were significant under different treatments of seed degradation at a probability level of 1% and shoot dry weight, root dry weight, seedling dry weight, shoot length and root length at a probability level of 5% were significant. With increasing seed decay period, germination percentage, germination rate, shoot dry weight, root dry weight, shoot length and root length decreased compared to the control, so that the highest percentage and germination rate were obtained in the control and the lowest in 96 hours of decay treatment. With increasing the rate of burnout in all traits showed a downward trend.

Seed germination and seedling emergence depend on the genetics of plant species and are also influenced by environmental factors. Genetics and nutritional status of the maternal plant, maturity stage at a time of harvest, and environmental factors such as temperature, salinity, drought, and soil fertility influence seed germination. Seed vigor as the main parameter of seed quality decreases due to accelerated aging and storage. The objective of this study was to evaluate the response of accelerated aged Chia seed to different levels of salinity stress.

Two-way factorial experiment with experimental factors, including five levels of seed accelerated aging durations (0, 24, 48, 72, 96 h) and six levels of salinity stress (0, 50, 100, 150, 200, and 250 mM) was arranged based on a complete randomized block design with three replications. The experiment was conducted at seed technology laboratory Khuzestan Agricultural Sciences and Natural Resources, University of Khuzestan, in 2019.

Results of analysis of variance revealed that the effect of seed accelerating aging, salinity stress, and interaction effects of both factors on all measured germination traits were significant (p<0.01). The best pattern of seed germination was evaluated using three-parameter sigmoid models (logistic, Gompertz, and sigmoidal) and two polynomial models (quadratic and cubic), then the performance of all models was compared using (R2adj), root square of the mean (RMSE) and corrected Akaike index (AICc). Results showed that at accelerated aging duration, modelschr('39') performance to describe Chia seed germination response varied at different levels of salinity stress. At no aging and 72h of accelerated aging treatments, the sigmoidal model exhibited the best fit on final seed germination, whereas for the other levels of accelerated aging, Gompertz exhibited the best fit. Based on the output of the sigmoidal model, for no aging and 72 hours of accelerated aging, 50% of seed germination was declined at 171.7 and 76.9 mM, respectively, and based on the results of the Gompertz model, after 24 and 48 h of accelerated aging, seed germination declined to 50% at 163.8 and 129.6 mM. Results obtained from fitting polynomial models on seed germination showed that the cubic model provides reasonable descriptions for studied traits such as seed vigor.

Chia seed germination was sensitive to salinity and accelerated aging treatments. At no aging condition, Chia seeds tolerate salinity stress up to 200 mM and were able to germinate. By increasing aging durations, seed germination declined dramatically at all salinity levels and after 96 hours of aging, there was no seed germination at 150 mM.

In order to study the effects of accelerated aging on quantitative and qualitative characteristics germination of Malva neglecta, Portulaca oleracea and Amaranthus retroflexus experiments a completely randomized factorial design were conducted in the research laboratory of the college of agriculture, University of Tarbiat Modarres during 2018. Treatments were accelerated aging, respectively, at five levels (0, 24, 48, 72 and 96 hours Placing seeds in an environment with a relative humidity of 100% and a temperature of 45 degrees Celsius) Were considered as the first factor and weed species as the second factor. The results showed that all traits were influenced by the interaction of factors. In optimum conditions (without accelerated aging) Portulaca oleracea and Amaranthus retroflexus highest percentage germination and seedling emergence. But, the results about the antioxidant enzyme activity and protein concentration was different in three weed species, so that the highest catalase activity was obtained in the Malva neglecta and Amaranthus retroflexus under 24 hours Seed aging treated and 72 and 96 hours seed aging treated on Portulaca oleracea. Overall the results of this study showed that, it was concluded that seed quality of weeds Species was seriously decreased under the aging conditions.

One of the most important stages in the life cycle is germination, which is controlled by various environmental and genetic factors. Temperature and water potential are the most important factors in germination control. Different models for quantization of germination response to temperature and osmotic potential have been used. Quantification of germination response to osmotic potential and temperature is possible using non-liner regression models. Therefore, this research was carried out to determine the cardinal temperature of germination (base temperature, optimum and maximum germination) of safflower of Sofeh cultivar under different osmotic stress (drought stress) conditions and seed deterioration.

In this study germination response to water potential in different temperature were studied. Treatments included osmotic levels (0, -0.4 and -0.8 MPa), temperature (5, 10, 15, 20, 30, 35 and 40 °C) and seed deterioration (0 and 5 days). Ccumulative germination response of seeds to differential water potential and temperature were quantified using three-parameter sigmoidal model. For quantifying response of germination rate to temperature for different osmotic potential were used of 3 non-linear regression models (segmented, dent-like and beta). The root mean square of errors (RMSE), coefficient of determination (R2), CV and SE for relationship between the observed and the predicted germination percentage were used to select the superior model from among the employed methods. Germination percentage and time to 50% maximum seed germination of safflower were calculated for the different temperatures and osmotic potential by fitting 3-parameter sigmoidal functions to cumulative germination data.

Results indicated that temperature in addition to germination percentage also on germination rate was effective. Also results showed that germination percentage and germination rate increased with increasing temperature, while germination percentage and germination rate reduced as a result of water potential increment. Results indicated that under different osmotic potential as 0, -0.4 and -0.8 MPa, the segmented model estimated base temperature as 2.23, 3.67 and 4.33 °C, the dent model estimated base temperature as 3, 3.96 and 4.33 °C, the beta model estimated base temperature as -1.22, -1.28 and -2.28 °C, the segmented model estimated optimum temperature as 23.05, 25.44 and 24.19 °C, the optimum temperature using beta model as 28.89, 28.99 and 26.46 °C, the dent-like model estimated lower limit of optimum temperature and upper limit of optimum temperature as 21.12, 21.92 and 20.16 and 30.07, 25 and 23.27 °C, ceiling temperature using segmented model were 40, 40 and 35 °C, using dent-like model were 40, 39.83 and 35 °C, using beta model were 40, 35 and 34.82 °C, the segmented model estimated fo as 23.02, 69.51 and 84.17 h, the dent-like model estimated as 27, 75.99 and 83.87 h and using beta model were 26.09, 75.09 and 103.41 h, respectively. In compared 3 models according to the root mean square of errors (RMSE) of germination time, the coefficient of determination (R2), CV and SE the best model for determination of cardinal temperatures of seed control of safflower for 0 MPa was dent-like model and for -0.4 and -0.8 MPa was segmented model and for seed deterioration of safflower in all osmotic potential was segmented model. In general, results indicated that lower limit of optimum temperature and upper limit of optimum temperature and ceiling temperature reduced but fo increased as a result of water potential increment.

Germination of safflower response to different temperatures and osmotic potentials, led to acceptable results. Utilizing the output of non-liner models at different temperatures can be useful in prediction of germination rate in different water potential.

In order to investigate the effects of accelerated aging and hydro-priming of seed on germination and growth characteristics of corn seedling (cv. single cross 701), a factorial experiment was conducted based on completely randomized design with three replications in the research laboratory of University of Maragheh, Iran in 2015 year. Factors included three level of accelerated aging of seed (zero (control) and 2 and 4 days) and three level of pre-treatment of seed (Non-priming and hydro-priming for a period of 12 and 24 hours). The results of analysis of variance (ANOVA) showed that the simple effect of aging of seed and hydro-priming on all studied traits was significant at 1% probability level, but only the interaction of aging of seed and hydro-priming was significant on ascorbate peroxidase activity, electrolyte leakage rate, germination percent and germination rate. Simple and interaction effects of aging of seed and hydro-priming on the ratio of plumule to radicle were non-significant. The results of the mean comparison showed that all of the traits were reduced due to aging of seed. The soluble proteins contents, superoxide dismutase activity, plumule length, radicle length and seed vigor index due to seed aging of 2 days were 13.7, 10.9, 14.8, 14.8 and 33.2%, respectively, and due to seed aging of 4 days, they decreased by 36.8, 33.4, 32.4, 35.0 and 67.9%, respectively, relative to the control (without aging of seed). The results indicated that by increasing the duration of the hydro-priming of seeds from 12 to 24 hours, the soluble proteins contents, superoxide dismutase activity, plumule length, radicle length and seed vigor index were increased. Based on the results of interaction effects it was found that in the non-aged seed (control) applying hydro-priming for 24 hours was the highest and in the aged seeds (for 4 days), no hydro-priming had the least ascorbate peroxidase activity and percentage and germination rate. According to the results of this research, it can be stated that hydro-priming (especially for 24 hours) can decrease some of the destructive and minor effects of seed aging, and this technique can be used for reduction of the damage caused by the aging of corn seeds.

Seed deterioration is a physiological phenomenon that affects all germination, biochemical, cytological, and growth characteristics of plants. So it is necessary to use seed vigor enhancement methods to resolve these problems. One of these methods is the application of seed priming techniques to reduce deterioration effects. Therefore, the present study aimed to investigate the effect of different pre-treatments by using Nano-zinc, ascorbic acid, humic acid, gibberellin and KNO3 on germination indices and chromosomal aberration of aged onion seeds.

This experiment was performed as factorial based on a completely randomized design with 3 replications (100 seeds per replicate) in the faculty of agriculture at Urmia University. The first factor was the level of aging at 4 levels (control, 12h, 24h, and 48h) and the second factor was seed pre-treatments at 6 levels (control, Nano-zinc (30 mg), ascorbic acid (100 mg), humic acid (150 mg), gibberellin (200 mg/l) and KNO3 (0.1%). Given that the germination was not similar at different levels of aging, the seeds were germinated at control and 12h of aging after 6 days, at 24 and 48h of aging after 8 and 9 days, respectively. Hence, germination percentage, germination rate, normal seedling, mean germination time, and seed vigor were evaluated after the mentioned times. Chromosomal aberrations were also examined.

The results showed that the interaction effect of aging and seed pre-treatments on germination indices were significant at %1 probability level. By increasing the period of aging, all germination characters decreased significantly. The highest germination percentage (80%, 70%, 50%) and germination rate (5.350, 3. 316, 1.525 seed/day) were obtained by using Nano-zinc At 12h, 24h and 48h ageing levels. Nano-zinc and gibberellin had the highest effect on seedling vigor and normal seedlings. Seedling vigor increased significantly by using Nano-zinc and gibberellin at 12h (1133, 933.9), 24h (742.9, 692), and 48h (369.9, 323.3). The chromosomal aberration was reduced by using pre-treatment.

In this study, the most effective pre-treatments to improve germination characteristics and reduce chromosomal aberrations were gibberellin (200 mg/l) and Nano-zinc (30 mg). Therefore, it can be stated that the use of Nano-zinc and gibberellin as seed pre-treatments can significantly reduce the effects of deterioration on onion seeds.

1- Nano-Zinc and gibberellin were the most effective priming treatments on seed germination and growth characteristics of the aged onion seeds. 2- Priming treatment reduced the percentage of chromosomal aberration in the onion and the highest effect was obtained using Nano-zinc and gibberellin.

Soybean (Glycine max (L.) Merrill) is the primary source of vegetable oil. Even in desirable conditions, soybean seeds lose their viability in long term storage. Many factors contribute to seed deterioration, including genetic factors, mechanical damage, relative humidity, storage temperature, seed moisture content, existence of microflora, and seed maturity, which reduce seed quality and make seeds unfit for cultivation purposes.

In order to investigate the effects of seed deterioration on seed germination and also the effects of salicylic acid and ethylene on the improvement of deteriorated seeds of G. max., accelerated aging test for 0, 6 and 10 days and natural aging test for 6 months were conducted. After aging conditions, seeds were imbibed with 50 µM salicylic acid and 10 µM ACC (precursor of ethylene) for 6 hours at 25 °C. In addition, after natural and accelerated aging tests, a bunch of seeds was used without any hormonal treatment (i.e., dry seeds) as control seeds. The seeds’ germination percentage, total sugar, fructose, and glucose were investigated. Moreover, the gene expression of GAI1 and LOX1 was measured on dry seeds and under imbibition of water, salicylic acid and ACC at 6, 12 hours using Q-RT-PCR method.

The germination results showed that increasing number of aging days led to a decrease in germination. Total sugar content in seeds aged for 6 days did not have a significant difference, as compared with non-aged seeds. However, total sugar content in seeds aged for 10 days was significantly higher than non-aged seeds. Increasing accelerated aging levels from 0 days to 10 days led to increases in glucose and fructose contents in dry seeds. In addition, genes exhibited different expressions in different days and hours. Increasing aging from 0 days to 10 days led to increases in GAI1 gene expression. Moreover, LOX2 expression increased in accelerated aging from 0 to 6 days. LOX2 gene expression in naturally dried aged seeds also increased and was higher than that in non-aged seeds. SA and ACC had different effects on measured values.

In general, it can be concluded that the deterioration of seed quality and vigor result from numerous degradation processes and disruption in seeds’ physiological activity. This study showed that aging is associated with an increase in total sugar, glucose and fructose levels. In addition, the expression of the genes involved in the germination is also affected. Increases in LOX2 gene expression were observed in both accelerated aging and natural aging pathways. GAI1 gene expression increased in accelerated aging. However, in normal aging, it decreased.

To study the effect of production region and seed size on germination indices and heterotrophic growth components of peanut seedling, a study was performed in three peanut fields in Astaneh Ashrafieh and Agronomy Laboratory of Rasht Islamic Azad University from 2010 to 2012. This research was carried out using the standard germination, cold and accelerated aging tests. Tests were performed using factorial experiment with a completely randomized block design in 3 replications. The first factor was seed production region in 3 levels (Noghredeh, Amshal and Bandar-Kiyashahr) and the second factor was seed weight in 3 levels [large, medium and small]. The results indicated that the effect of production region on the germination speed (p

Seeds could be deteriorated during storage. Treatment of seeds by humic acid induces metabolic and biochemical changes which accelerate seed germination and its emergence. This research was carried out to evaluate the effect of seed pretreatment potassium humate on its deterioration under laboratory and greenhouse conditions. The experiment was carried out in a 5 × 4 × 3 factorial experiment using completely randomized design with three replications. Experimental factors were three levels of potassium humate (control, one and two parts per 1000 potassium humate), four wheat varieties (Shirodi, Darya, Morvarid and Chamran) and five heating times (zero, 48, 72, 96 and 144 hours). Results showed significant differences in simple effect of variety and effect of potassium humate × heating times for shoot length; simple effect of heating times and effect of potassium humate × varieties for germination percent; effect of potassium humate × varieties × heating times for radicle length, shoot dry weight, seminal roots dry weight and seedling dry weight. Pretreatment of seeds by using 2/1000 potassium humate produced × longest radicle roots in Shirodi, Darya, Morvarid and Chamran respectively with 72, 72, 144 and 96 hours heating times. The highest root dry weight was produced by 2/1000 potassium humate and 48 and 72 hours of heating times on Shirodi and Chamran, respectively. Application of 1/1000 of potassium humate produced the highest seedling dry weight in Shirodi, Darya and Morvarid with 48, 72 hours of heating times and without heating, respectively. Results also revealed that different varieties responded differently to potassium humate treatment at different heating times. It can be concluded that longer heating durations affected wheat characters at early growth stages and pretreatment of seeds by potassium humate can decrease seed deterioration.

The objective of the present study was to assess the combined effects of drought stress and foliar application of zinc and manganese on seed quality of red bean (Naz variety) during the accelerated aging test. The experiment was carried out as split factorial in a randomized complete block design (RCBD) with three replications at the research farm of Shahrekord University during 2010-2011. Drought stress levels (irrigation after 50، 70 and 90 mm evaporation from class A evaporation pan) was used as the main plot factor، while factorial combination of zinc and manganese foliar application (0، 100، 200 and 0، 150، 300 g. ha-1 for zinc and manganese، respectively) were used as sub-plots. After harvesting the seeds and preparation of composite samples، seeds were evaluated through the accelerated aging tests with four replications. The results showed that drought stress didn’t have any significant effect on germination indices. Mn foliar application increased germination rate، seedling dry weight and vigor indices (I and II). In between، Mn foliar application at the rate of 150 g. ha-1 had the maximum effect on germination indices. Between Zn foliar application levels، maximum seedling length، dry weight and vigor indices (I and II) were obtained for application of 100 g Zn per hectare. Based on the results of this study، drought stress with application of low concentration of Zn and Mn improves seed quality during the accelerated aging test as well as the seed storage capabilities.

Quality evaluation of seed which is considered as a crop propagation organ and the most important input for crop production، has a special position in seed production and certification. This experiment was conducted to study the effect of different packages on oil rapeseed varieties. The studied cultivars were RGS، Talaieh and Okapi and packaging cover types were three –layer paper bag، 4-layer paper bag، propylene bag،propylene+paper and flaxen bag which was studied using factorial experiment on the basis of randomized complete block design in 3 replications. The seed containing bags were stored in Ran corporation in Firoozkoh for 1 year and standard sampling of each treatment and replication was done at the end of the storage period then seeds germination was tested. Also electrical conductivity test، average time for germination cold test and accelerated aging test have been conducted for estimating seed vigor. The results showed significant difference between cultivars in cold test and Talaei was the best، but seeds storage in the various bags had a significant effect on seed vigor as seeds in four layer and three layer paper bags had the most vigor and seeds in propylene bags and paper propylene bag had the least vigour. Also the results showed that various seed storing covers have significant effect on the average time of seeds germination، electrical conductivity and vigor after cold test and accelerated aging test and in all cases three and four layer paper bags showed the best resulting. However propylene and paper propylene bags had more deteriorating effect on seed quality. Since in the warehouse the temperature had increased up to 35°c and air relative humidity up to 75% in some months of the year، and with considering that high temperature may accelerate the incidence of some metabolic reactions and either seed deterioration، so the temperature and relative humidity have more effect on propylene and propylene paper bags.