نشریه پژوهش های بذر ایران
سال سوم شماره 1 (پیاپی 5، بهار و تابستان 1395)

Priming of seeds by magnetic fields (magneto priming) is proposed as an ecological, useful and low-priced method for improvement of seed germination and plant emergence. In order to evaluate the germination behavior of sesame seeds affected by magnetic fields, an experiment was conducted as a completely randomized design with 22 treatments (non exposure to magnetic fields (control) and 21 magneto priming treatments) with three replications at college of agriculture, Ferdowsi University of Mashhad in 2014. Seed of sesame put into a plastic bag bulky and were treated with different intensity of magnetic fields (25, 50, 75 and 100 mili Tesla (mT)) for several times (10, 20, 30, 60 and 120 minutes). For assessment of germination traits of sesame under constant magnetic field conditions, magnetic tapes with three mT strength were used under each Petri dish throughout the experiment. Results showed that magnetic fields had no significant effects on final germination percentage and mean germination time and all magnetic treatments except for 75 mT at 60 minutes indicated reducing effects on germination percentage in comparison to control. Priming of seeds with magnetic fields in 50 mT strength for 20 minutes led to increment of germination rate compared to control treatment but all levels of 100mT treatment caused reduction in germination rate than control. The most radicle length, seedling length and seedling vigor lenght index belong to 75 mT at 60 minutes treatment and the most seedling dry weight and seedling vigor weight index related to 100 mT for 20 minutes treatment. Ranking of treatments showed that exposure of seeds for one hour in 75 mT and 10 minutes in 25 mT magnetic fields strength had the best outcomes.

In this study, the effect of different doses of gamma radiation was investigated on seed germination factors of Caper species. Gamma irradiation was performed using a cobalt-60 radiation with the radiation speed of 0.018 Gray/second and five doses of gamma radiation (0, 20, 40, 60 and 100 Gray) in a completely randomized design with 4 replication. The results showed that gamma radiation significantly affects some of the seed germination factors. So that the 100 Gray treatment increased the germination percentage up to 43.2% as compared with other treatments. The average time of germination in seeds treated with gamma decreased 0.91 days rather than control. Length of the stem let in gamma treatments increased 62.3% rather than control; so that the fresh and dry weight of stem let at 100 Gray were respectively increased 171.4 and 27.3% in comparison with the control. Fresh and dry weight of root lets were respectively increased 417.9% and 668% rather than the control one. Seed vigor at 100 Gray was 32.3% higher than the control. From among the different studied doses, 100 Gray showed highest influence on the seed germination and physiology although the induced changes were in low amounts. This study revealed that gamma irradiation has not major influences on improving seed germination characteristics of Caper shrubs.

Medicinal barberry plants, belong to Berberidaceae family. Seeds of barberry have long period dormancy. Therefore, overcome to seed dormancy and increasing germination rate of seeds due to different methods will be useful. In this regard, two separate experiments were designed. In the first experiment, effect of different levels of Gibberellic acid (0, 600 and 900 mg.l-1 at 8˚C) and temperatures (25 (control), 10 and 5 °C at 50 days) in a factorial experiment based on the completely randomized design with three replications and in the second experiment, effect of different nutrition concentrations of MS medium (full strength MS, 1/2MS and 1/4 MS) in a completely randomized design with three replications on embryo culture of four native species of barberry (Berberis integrima, B. vulgaris, B. crataegina and B. orthootrys) were investigated. Based on the results obtained from the first experiment, chilling treated seeds showed the greatest effect (88%) on seed germination in comparison with gibberellic acid treatment. The results of the second experiment showed that the best MS concentration for embryo culture was full strength MS medium with%100 seed germination in four above mentioned barberry species after 2-3 days. In general, the best method to overcome barberry seed dormancy was an embryo culture in full-strength MS nutrition.

Seed priming is a method which is a quite effective method in improving germination and seedling establishment. Two separated experiments were performed to determine the best hydro and osmopriming treatments effects on canola‘s seed germination. The experiments were performed in seed technology laboratory of Islamic Azad University, Karaj, Iran, 2014. The first experiment contained three canola varieties seeds hydropriming (Okapi, Zarfam and Talayeh) using tap water over time interval 0. 2, 6, 10, 14, 18, 20 and 24 hours. The second experiment included, tree canola cultivars in accompany with six concentrations of ZnS04 (0, 0.035, 0.1, 0.4, 1 and 4 gr.Lit-1) over priming time interval of 0, 6, 10 14 and 18 hours. Both experiments were conducted as factorial experiment in the context of completely randomized design (CRD) with four replications. The results revealed that the maximum germination percentage across all cultivars e.g. Okapi (99%), Zarfam (95%) and Talayeh (80%) is achieved at 10 hours hydropriming interval. Also concerning to germination rate, the best performance was observed for Talayeh cultivar at 10 hydropriming hour’s interval. The most vigor longitudinal and vigor weighted indices (1050.55 and 4.56) were observed in the Okapi cultivar in the fourth hydropriming level. The interaction between the cultivars, concentration of ZnS04 and osmopriming time was significant for all characters except for shoot dry weight and vigor weighted Index. The three way interaction shown that the highest shoots dry weight (0.11, 0.057 and 0.055) and also vigor weighted index observed in Okapi, Zarfam and Talayeh cultivar in 0.035 concentration of ZnS04 (gr.lit-1) at the time was 10 hours, respectively. The results of this study showed that hydropriming and ZnS04 might improve the performance of rapeseed Cultivars seed.

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

The seed pretreatment with salicylic acid has an important role in improving seed germination and increasing plant resistance to environmental stresses. This study was performed to investigate the effect of salicylic acid on seed germination of Milk thistle under salinity and drought stress. A factorial experiment was conducted in a completely randomized design with three replications. Treatments were consisted of 4 levels of salicylic acid (0, 100, 200 and 300 mg/l) and four levels of each drought and salinity stress (0, - 4, - 6, - 8 Bar). The results showed an interaction effect between pretreatment with salicylic acid and drought and salinity stresses was significant at the 1 % level. On high salinity level (-8 Bar), seed germination percentage and rate, root and shoot length, fresh and seedling dry weight reduced significantly. The short length, fresh weight and percent germination reduced in all three levels of drought stress. Pretreatment with salicylic acid (200 and 300 mg/L) significantly reduce the harmful effects of drought and salinity stress (-6 and -8 Bar) on germination and seedling growth parameters of Milk thistle. The results of this experiment showed that seed treatment with salicylic acid can lead to increase resistance of Milk thistle to salinity and drought stress in seed germination.

The need to identifying seeds with low vigor and poor emergence, led to introduce of various seed vigor tests. The purpose of this experiment was to assess the ability of controlled deterioration test for evaluation of seed vigor and prediction of oilseed rape seedlots emergence in the field. Samples of 19 seed lots were obtained from nineteen farmers of Razavi and Northern Khorasan Provinces, which have been cultivated during 2009-2010 growth season, set to physiological germination test before and after controlled deterioration (CD). The estimating of seedling emergence percentage of each seed lot in the field, calculated 30 days after sowing. The correlation between laboratory results before and after CD of seeds and field emergence showed that correlation of final germination, normal seedlings and mean germination time before CD with emergence in the field respectively with 0.072, 0.24 and 0.042 correlation coefficient, were not significant, but laboratory results after CD had significant correlation with emergence of seedlots in the field. As, final germination, normal seedlings and mean germination time respectively with 0.57, 0.51 and 0.49 correlation coefficient predict emergence percentage of seed lots in the field. High correlation between laboratory results after controlled deteriorated test with seedling emergence in the field indicated that the CD test is able to assess the field emergence of oilseed rape seed lots before sowing.

Germination is the first and the most stages for sainfoin (Onobrychis viciifolia) growth; which it has specially sensitivity to environmental stresses such as alkalinity. The current study was conducted to evaluate the effectiveness of seed pre-treatment methods on improving of sainfoin tolerance to alkali stress in germination, early growth and its recovery as a factorial experiment based on a completely randomized design in College of Agriculture, Shiraz University in 2013. The first factor was four seed pre-treatment methods (seed with pod, seed without the pod, pre-chilling of seed without pod and hydro-priming of seed without pod) and the second factor was five alkali stress levels (pH= 6.7, 7.9, 8.9, 9.8 and 10.7). Alkali stress levels were prepared using two neutral salts (Na₂SO4 and NaCl) and two alkaline salt (NaHCO3 and Na2CO3). The results showed that germination percentage was decreased as alkalinity (pH) levels were enhanced; so that, there were no germinated seeds in 9.8 and 10.7 treatments. Alkali stress reduced initial germination percentage (51.9%), final germination percentage (51.8%), plumule length (55.7%) and radicle length (72.2%). Under all alkalinity conditions, the lowest seed germination and seedling growth were observed in with pod seed, followed by pre-chilling treatments; while their highest were achieved in without pod seeds and hydro-priming treatments. The highest recovery was observed in without the pod, followed by hydro-primed seeds. Recovery was observed in Pre-chilled and with pod speeds up to 7.9 and in hydro-primed and without pod speeds up to 8.9.

The objective of this research was to evaluate the effect of salicylic acid and gibberellic acid on germination characteristics and changes of proline, protein and catalase activity of Brassica napus seedlings under Cu(SO4) stress. The experimental design was factorial with complete randomized design as a base design with 3 replications. The first factor was 4 levels of Cu(SO4) stress (0, 10, 20 and 30 mg/l), and the second factor was 4 levels of priming with salicylic acid and gibberellic acid 50 mg/l, hydro prime and control (non-priming). Results showed that with increasing levels of Cu(SO4) stress, germination characteristics (germination percentage, germination rate, normal seedling percentage, seedling length and seed vigor index) reduced and using of salicylic acid, gibberellic acid and hydro prime increased germination characteristics. The highest germination percentage (94%), germination rate (30.75 seed per day), normal seedling percentage (86.17%) seedling length (10.53 cm) and seed vigor index (9.08) were attained from priming by salicylic acid 50 ppm under non stress conditions. Cu(SO4) stress increased proline (35%) and catalase (37%) activity but reduced protein (65%) and priming increased proline, protein and catalase activity as compared to unprimed under stress and control conditions. In this study, using priming treatment salicylic acid had usually higher germination characteristics and catalase activity, total proteins and proline content in comparison with untreated or control seeds.

Efficient seed germination and rapid and uniform seedling emergence are important in commercial agriculture. Therefore, the use of strategies to improve germination and seedling establishment is necessary for increasing productivity. Hydropriming has been suggested as a simple pre-germination strategy to improve seed performance. In this study, the effects of different durations of hydropriming (10, 24, 48 and 72 hours) at different temperatures (10 and 25 ˚C) compared to unprimed seeds on the vigor and germination performance of five milk thistle accessions (Ahvaz, Sari, Esfahan, Dezfol and Gachsaran) were evaluated. An experiment was conducted as a factorial experiment based on a completely randomized design with three replications. Germination performance was evaluated by final germination percentage, mean daily germination, mean germination time, coefficient of velocity of germination, Timson's index, time to reach 50% the final germination percentage, germination value, coefficient of uniformity of germination, length and dry weight of seedlings and vigor index. The results show that germination capacity, germination rate and seedling vigor indexes increase significantly in hydroprimed seeds at temperature of 10˚C, whereas decrease in hydroprimed seeds at temperature of 25˚C. Our results also show that the efficacy of hydropriming on seedling emergence and vigor traits depends on the priming duration and temperature. Hydropriming at 10˚C indicated the most effective on germination indicators and seedling vigor when compared to unprimed seeds. In addition, the comparison of germination and growth indicators in different durations of hydropriming in five milk thistle accessions indicated that the best duration of hydropriming for Ahvaz and Gajsaran is 72h, for Sari and Dezfol is 48 and 72h and for Esfahan is 10 and 24h. Therefor, the effect of hydropriming on germination performance and seedling vigor depends on plant association and hydroperiming time and therefore, the selection of the best condition for hydropriming will improve the seed germinability and vigor.

In order to study the salt tolerance of three species, Coreopsis grandiflora, Celosia cristata and Matthiola incana in germination stage, an experiment was carried out based on a completely randomized design with three replications in Hormozgan University laboratory in 2015. Salinity levels, including 3, 6, 9, and 12 dS/m were applied by dilution seawater and distilled water used as control. In this research some seed germination indices such as germination percentage, germination rate and mean germination time, length, fresh and dry weight of seedling, seed vigor germination, were measured. Germination percentage, germination rate, seed vigor and dry weight of Coreopsis grandiflora seedling, were significantly different compared with control. In Celosia cristata, germination percent, seed vigor germination and seedling length didn’t show significant difference until 9 dS/m salinity. In more characters, significant increasing were seen with increasing salinity (9 dS/m). Germination percentage were decreased in comparisons with control (24.6%). In additional, fresh and dry weight of seedling didn’t show significant difference. The effect of salinity on seed germination of Matthiola incana in different level of salinity was not significant. Although seed germination decreases gradually by salinity. In general, according to the observed results, Coreopsis grandiflora and Celosia cristata showed more tolerance to salt in comparison with Matthiola incana.

There have been a little studies on removing the seed pods in annual medics, despite its importance. To investigate the role of pod removal on seed germination, seedling growth and antioxidant enzyme activities in annual medic (Medicago scutellata L.) Under salt stress, a factorial experiment was conducted based on a completely randomized design with four replications in 2014. Salinity at 5 levels: 0.62 (tap water as control), 3, 6, 9 and 12 dS m-1 was applied using sodium chloride. The results showed that salt stress caused changes in the characteristics of germination, seedling growth and antioxidant enzyme activities. With increasing in salinity levels, rate and percentage of germination as well as root length, shoot length and seedling weight was significantly decreased. However, increasing salinity levels increased the activity of antioxidant enzymes. Germination and growth in seed without pod was greater than those in seeds with pod; however, there were no significant differences between antioxidant enzyme activity; except about ascorbic peroxide that was significantly higher in seed without a pod. In general, salinity reduced germination and growth and increased antioxidant enzyme activity of annual medics. The results showed that planting seeds without pod had advantages for better germination and growth, especially under saline conditions.

In order to study the responses of redstem filaree (Erodium cicutarium L.) seed germination to temperature levels, an experiment was carried out in a completely randomized design with four replications and twelve levels of temperature (0, 3, 5, 7, 10, 12, 15, 20, 25, 30, 35, 40 0C). Results showed that the effect of treatments on germination properties of redstem was significant, so the highest percentage of germination was achieved at 150C and reduced with increasing temperature and was totally inhibited at 40ºC. Based on linear regression between germination rate and temperature, the cardinal temperatures: minimum (Tmin), optimum (To) and maximum (Tmax) were determined: 0, 15.20 and 37.18 ºC, respectively. Significant difference was not observed in plumule length at a range of 5-30°C that showed that it is less sensitive to temperature in comparison with root length. Highest wet dry weight was achieved at 20 °C that was not different by 10, 12 and 20°C. Above results suggest that redstem failure could grow in a wide range of growing conditions, but prefers temperate zones. The results of this study are important to understand thermal requirements and improvement of management strategies of redstem filaree.

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