نشریه علوم و تحقیقات بذر ایران
سال پنجم شماره 2 (تابستان 1397)

To study the effect of seed priming on forage and seed quality and quantity of cultivated amaranthus, a field experiment was conducted as randomized completely block design with six treatments and three replications in experimental of college of agriculture of Urmia University on 2013 cropping season. Treatments were seed priming of pigeon manure (10%), concentrated vaniaz 68.39% (3*1000) super macro plus nano chelate fertilizer (3*1000), magnet water, Homeopathy 12x and control. The seeds were soaked in the listed treatments for 8 hours; therefore those were brought to the initial moisture content for 24 hours at 25◦C.therefore those were brought to the initial moisture content for 24 hours at 25 ◦C and transmitted to field for planting. Harvest was at flowering stage in one square meter of each experimental unit. In current study were including Steam dry matter, Leaf dry matter, Leaf to stem ratio, Forage yield, P, K, C and seed yield, oil percent and yield, protein percent and yield were evaluated. Treatment effect on steam dry matter (306.5 gr m-2), leaf (255.8 gr m-2), Forage yield (7809.7 kg ha-1), CaO (20.4 gr kg-1), P2O5 (3.9 gr kg-1), seed yield (798.2 kg ha-1), oil % (12.2%), oil yield (217.5 kg ha-1), protein % (13.8%), protein yield (234.5 kg ha-1) was significant and increasing. According to obtained results, using magnetic water and nano chelate pretreatment was lead to quantitative enhancement more than others.

In order to evaluate the effect of accelerated aging on antioxidant compounds and germination indices of barley, an experiment was conducted as factorial in a completely randomized design on eight native barley genotypes and two barley varietyBehrokh and Nosratwith three replications. The first factor was seed aging at two levels including aging and non-aging as control and the second factor was ten barley genotypes that the varieties were as control. Germination percentage of the most genotypes decreased after aging although it has not significant difference with non-aged seed. The results showed that accelerated ageing decreased significantly germination rate, shoot length and root length, concentration of photosynthetic pigments and catalase (CAT) activity. However mean germination time and total phenol content of genotypes and Behrokh and Nosrat varieties increased significantly after seed aging. Genotype 3 had the highestenzyme CAT activity after ageing. Increment of phenol content was different among the genotypes and genotype 8 had the highest phenol content before and after aging rather than the other genotypes and it affected less than the other genotypes by accelerated ageing. Totally the results of thisstudyindicated that genotypes that initially had high phenolic content and enzymatic activity also had vigor and germination rate after seed aging.

This study was done to evaluate different linear and nonlinear regression models to determination of cardinal temperatures and biological day's requirement for emergence of lentil. Therefore, a split plot experiment was conducted based on three replications. Seeds of lentil (Gacgsaran, Kimia and Bilehsovar) were sown in field at 12 different dates. Beta, dent-like and segmented models were applied to evaluate the relationship between germination rate and temperature. Root mean square deviation (RMSD), coefficient of determination (R2), variation coefficient (CV (and linear regression coefficients (a and b) were used to select the perfect model. Results of models fitting indicated that the response of lentil emergence to temperature is best described by a segmented model. Cardinal temperatures estimated by this model were -1.27 to -1.62°C for base temperature, 23.15 to 25.92°C for optimum temperature and 30°C for ceiling temperature based on air temperature. There was not any significant difference among cultivars in view of in base temperature and optimum temperature but cultivars had significant difference in biological days. The biological day’s requirement was 6.99, 8.56 and 8.78 for Bilehsovar, Gacgsaran, and Kimia, respectively. The quantitative information provided in the present study can be used to predict the emergence of lentil cultivars.The main applicable result of this study was that reaction of seedling of the lentil is describable best by the use of segmented model, so this model and its derived parameters are applicable in predicting emergence in some given lentil cultivars.

Harvesting time is one of the most important factors affecting the seed quality. In order to determine the effects of harvesting time on quantity and quality of plantago major seeds, two experiments were carried out in the Ferdowsi University of Mashhad in 2014. In the first experiment six plantain ecotypes (Birjand, Ghaen, Torbat Hydarieh, Mashhad, Kalat and Bojnord) grown in the field and plant spikes were harvested in six stages with 15 days interval (15, 30, 45, 60, 75 and 90 days after 50% pollination), then germination of harvested seed was tested in the laboratory. Number of spike per plant and its length after 50% of pollination increased and reached to the maximum in 75 and 60 days after that, respectively. Kalat ecotype had the fewest and the shortest spikes, while Birjand and Bojnoord ecotypes produced the longest spikes. The maximum seed weight per spike for Kalat and Bojnoord ecotypes was obtained at 90 days after 50% pollination, while in the other ecotypes it was observed at 75 days after that. The highest germination, speed germination length and weight vigor index in Ghaen ecotype was observed at 75 days after 50% pollination, while in the Torbat Hydarieh ecotype they were observed at 45 days after 50% pollination. In Ghaen, Torbat Hydarieh and Mashhad ecotypes delaying in harvest time of 75 days after 50% pollination causes seed losses and reduction in seed germination.

In order to study the effects of seed priming by ascorbic acid (0, 40, 60 and 80 mM) to increase salt tolerance (0, 100, 150 and 200 mM NaCl) in moldavian balm at germination stage, an experiment was conducted as factorial in a completely randomized design with three replicates at Shahrekord University (2015 year). Evaluated parameters consisted of germination indices (germination percentage and rate, length and dry weight of seedlings and seed vigor index) and the activity of catalase, ascorbate peroxidase and guaiacol peroxidase. Results showed the values of germination indices significantly decreased with increasing salinity degree. However, seed priming by ascorbic acid (40 mM) decreased the negative effects of NaCl on germination of moldavian balm. At this level of priming and under 100 mM NaCl, seed vigor index increased by 32% and at 150 mM NaCl it increased by 2.7 folds. Since the activity of antioxidant enzymes was in coordinate with the effect of optimal concentration of ascorbic acid under salt stress, it is concluded that priming with ascorbic acid decreases oxidative stress due to NaCl by enhancing the activity of antioxidant enzymes in the tissues of moldavian balm and consequently salt tolerance increases in this plant at seed germination.

In order to investigate the effects of hydro-priming duration on green cover and leaf chlorophyll and carotenoid contents of milk thistle (Silybum marianum L.) under different irrigation treatments, a split plot experiment based on randomized complete block (RCB) design with three replications was conducted in 2015 at the Research Farm of the University of Tabriz. Irrigation treatments (I1, I2, I3, I4: Irrigation after 70, 100, 130 and 160 mm evaporation from class A pan, respectively) were allocated to main plots, and hydro-priming durations (P1, P2, P3: 0, 8 and 16 hours, respectively) were assigned to the sub plots. Germination percentage, mean germination time, number of plants per unit area, percentage of green cover, chlorophyll a, b and total and carotenoid contents were measured. The results showed that hydro-priming especially in 16 hours was reduced the mean germination time. However, had no significant effect on germination percentage. Also, the number of plants per unit area increased with increasing priming duration up to 16 hours. Percentage of green cover was also enhanced with increasing hydro-priming duration under all irrigation treatments. Chlorophyll a, b and total and carotenoid contents considerably decreased as a consequence of water deficit. However, hydro-priming for 8 and especially 16 hours significantly increased these traits. These results clearly indicate that hydro-priming by increasing plant establishment, percentage of green cover and chlorophyll and carotenoid contents has reduced drought effects. This could improve grain production of this medicinal plant under well and limited irrigation conditions.

In arid climate area like Iran, selection of adapted species plays an important role for afforestation. Robinia peseudoacacia is fast growing and resistance to such an extreme heat and cold conditions of environment and can grow in unfertile soils but posses' seeds covered by hard coat. Therefore, success in planting and germination needed to application of some treatments to remove the coat. The aim of this study was the determination of the best provenances and treatments in terms of Robina seed survival and germination percentage for using in afforestations. The experiment was carried out using Robinia seeds collected from six provenance: Sabzevar, Semnan, Gorgan, Mazandaran, Tehran, and Kordestan using completely randomized design. Tetrazolium test was done for seeds viability. The scarification treatments such as acid, boiling water, oxygen peroxide, normal water, scarification with sandpaper were applied on seeds. The Results showed that scarification with sandpaper induced thehighest germination among all treatments and in the most of provenances. Moreover, the seed provenance had a significant effect in germination of Robinia seeds, therefore it can be introduced that the Gorgan and Tehran provenances are the best and the worst provenances with 73.03% and 48.18% germinating percentage, respectively.

Germination and emergence of seed is strongly influenced by environmental stresses such as salinity and drought. In order to study the germination response of common daisy (Bellis perennis L. “Bellissima Mixture”) seeds to salinity and drought stresses, two separate experiments were carried out based on completely randomized design with 3 replications. Drought and salinity treatments were seven osmotic potential levels (0, -2, -4, -6, -8, -10 and -12 bars) applied using polyethylene glycol (PEG) and sodium chloride (NaCl), respectively. The results showed with increasing levels of drought and salinity, germination percentage decreased and at potential level of -12 bar of drought and salinity, it reduced to zero and 50%, respectively. Drought and salinity stresses significantly decreased germination rate from levels of -2 and -8 bar to higher compared to control, respectively. Moreover, drought and salinity stresses significantly reduced radical length, plumule length and dry weight of radical, plumule and total. With increasing levels of salinity to -10 and -12 bars, plumule length values decreased by 42 and 67% compared to control, respectively. Proline content significantly increased by drought and salinity stresses, but the amount of proline under drought stress was higher than salinity. The results of this study showed that the salinity tolerance of common daisy in the germination stage was higher than drought stress.

In order to study some morphological and physiological traits of susceptible (Hayola308) and tolerant (SLM046) genotypes of canola to drought stress, an experiment was conducted in CRD design with factorial split in time arrangement. The applied factors were genotype (susceptible and tolerant) and irrigation condition (non-stress and stress). The stress was applied at before flowering time and the traits were measured at 24, 48, 72 and 96 hours after it in both condition. The result showed a reduction in dry weight of root in Hayola308 genotype, and a significant increase in root to shoot length ratio, fresh weight of root and malondialdehyde level (MDA) in SLM046 genotype. The 48 hours after drought stress, the fresh weight of shoot in SLM046 genotype was higher than Hayola308 genotype. Relative water content (RWC) in SLM046 and Hayola308 at 24 hours after stress were 88.59% and 38.52%, respectively. In Hayola308 genotype, hydrogen peroxide (H2O2) content in stress condition was higher than non-stress ones. There was not a significant difference among studied treatments for electrolyte leakage. In general, the increase of root length, root to shoot length ratio, RWC, fresh weight of root and the difference between fresh and dry weight of root and shoot and no change in dry weight of root and H2O2 content in SLM046 genotype indicated that this genotype had traits which could assign tolerance to drought stress.

This experiment was conducted to evaluate the changes in deterioration of two different sources of seed corn in two different conditions. Treatments were two seed origins production (Karaj and Moghan), seed storage in two regions (controlled warehouse& Warehouse in Moghan climate), seed asepsis at two levels (Aseptic& non-aseptic). Experiment was done as a factorial experiment based on completely randomized design with three replications. Measured characters included: normal seedlings percentage, mean time germination, seedling length and weight vigour indices, normal seedlings percentage in cold test, radical emergence percentage, catalase and peroxidase activities and malondialdehyde contents. Results illustrated seeds produced in Karaj compared to Moghan 4 %, maintained seeds in controlled warehouse compared to non-controlled 3%, and aseptic seeds compared to non-aseptic 2 % had more normal seedlings. Catalase activity in seeds produced in Karaj, were substantially higher (14 %) than the same seeds in Moghan. Seed treatment had no significant effect on catalase activity. Seed treatment had significant effect on peroxidase activities and malondialdehyde contents. peroxidase activity in aseptic seeds was about 11% higher and malondialdehyde was about 8 % lower than non-aseptic seeds. Interaction of seed source and seed storage on normal seedlings percentage in cold test, Peroxidase activity and malondialdehyde contents were substantially considerable. It means seeds produced in Karaj and maintained in controlled warehouse had the highest percentage in normal seedlings (92 %), Peroxidase activity (0.042 umol H2o2/min/mg protein) and had the lowest rate of malondialdehyde (3 nmol/gfresh weight). Thus the reducing of antioxidant enzymes activity leads to disruption of germination, vigour and seed deterioration.