نشریه علوم و تحقیقات بذر ایران
سال هفتم شماره 4 (زمستان 1399)

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.

To investigate the effect of light quality on germination indices and some vegetative traits of valerian seedlings, a research was conducted as completely randomized design with three replications and light combinations in four levels (R light, 15% B + 85% R , 30% B + 70% R and fluorescent light) were used. The results showed that the highest percentage of germination (63%), germination rate (%41.87), mean daily germination (9.21), germination value (68.81), peak value (7.50) and lowest mean time to germination (2.66) were obtained under R light.The highest dry weight of plumule (0.36 mg/seedling) were obtained under R light and 15%B + 85%R ratio. The highest dry weight of radicle (0.3 mg/seedling) were acquired under30%B + 70% R and 15%B + 85%R ratios. The highest length of plumule and radicle (1.18 and 3.03 cm, respectively) were obtained under R light and 15%B + 85%R ratio. The highest amount of radicle and plumule soluble sugar (63.37 and 72.54 mgg -1 FW, respectively) were acquiredunder R light and 15%B + 85%Rratio. The highest amount of chlorophyll a, b, totalchlorophyll (0.37, 0.47, 0.84 mg g -1 FW, respectively) and carotenoids (0.44 mg g -1 FW) were obtained under 30%B + 70%Rratio, the highest amount of radicle and plumule antioxidant activity (60.09% and 71.04%) under 30%B + 70%R and 15%B + 85%Rratios and the highest amount of radicle and plumule phenolic compounds (4.40 and 8.65 mg g -1 FW, respectively) under 30%B + 70%R and 15%B : 85%Rratios were obtained. The results of this experiment showed that it is possible to improve germination indices and biochemical and vegetative traits of valerian seedlings by the usage of the R and B spectra compare with fluorescent light.To investigate the effect of light quality on germination indices and some vegetative traits of valerian seedlings, a research was conducted as completely randomized design with three replications and light combinations in four levels (R light, 15% B + 85% R , 30% B + 70% R and fluorescent light) were used. The results showed that the highest percentage of germination (63%), germination rate (%41.87), mean daily germination (9.21), germination value (68.81), peak value (7.50) and lowest mean time to germination (2.66) were obtained under R light.The highest dry weight of plumule (0.36 mg/seedling) were obtained under R light and 15%B + 85%R ratio. The highest dry weight of radicle (0.3 mg/seedling) were acquired under30%B + 70% R and 15%B + 85%R ratios. The highest length of plumule and radicle (1.18 and 3.03 cm, respectively) were obtained under R light and 15%B + 85%R ratio. The highest amount of radicle and plumule soluble sugar (63.37 and 72.54 mgg -1 FW, respectively) were acquiredunder R light and 15%B + 85%Rratio. The highest amount of chlorophyll a, b, totalchlorophyll (0.37, 0.47, 0.84 mg g -1 FW, respectively) and carotenoids (0.44 mg g -1 FW) were obtained under 30%B + 70%Rratio, the highest amount of radicle and plumule antioxidant activity (60.09% and 71.04%) under 30%B + 70%R and 15%B + 85%Rratios and the highest amount of radicle and plumule phenolic compounds (4.40 and 8.65 mg g -1 FW, respectively) under 30%B + 70%R and 15%B : 85%Rratios were obtained. The results of this experiment showed that it is possible to improve germination indices and biochemical and vegetative traits of valerian seedlings by the usage of the R and B spectra compare with fluorescent light.

Two separate factorial experiments based on the completely randomized design were conducted at the Research Center for Plant Sciences, Ferdowsi university of Mashhad. In the first experiment, the effect of 0, -2, -4, -6, -8, and -10 bar of moisture regimes with three priming levels including control (without priming), halo priming by calcium chloride, and hydropriming were investigatedon the seed germination of rice. In the second experiment, the seeds primed similar to the first experiment were cultivated in the pots filled with sand, being under five levels of moisture regimes including control (filed capacity), 20, 40, 60, and 80% of field capacity. After 28 days of cultivation, some morphophysiological traits were measured. The results of the first experiment showed that under low moisture regimes the germination traites were negatively affected. However, under some moisture regimes, the use of priming improved the germination rate and percentage, and increased dry weight of radicle and hypocotyl. It was also found that improving effects of hydropriming was more than halopriming. In the second experiment, low moisture regimes significantly decreased seedling height, shoot dry weight, leaf area, root area and diameter, water relative content, and membrane stability index. Under this condition, seed priming treatment did not positively affect these traits, butincresedstomatal resistance and chlorophyl conten.According to the results, it seems that both under control and low moisture regimes the use of seed priming, specially hydropriming, can be beneficial for Riceseed germination.

This study was carried out to investigate the effect of corn seed priming on germination and physiological characteristics of corn seedling (SC 704) in two separate experiments, each in a factorial experiment with completely randomized design with four replications. In both experiments, the first factor was the priming solution of Sodium Sulfate, Sodium Chloride and Potassium Ntrate at 2% concentration and the second factor was the salinity treatment (0, 40 and 80 mM Sodium Chloride). The results showed that salt stress decreased germination percentage and seedling growth, α-amylase activity and cell membrane stability of maize seeds in primed and non- primed seeds, whereas priming with Potassium Nitrate solution and Sodium Chloride had a positive effect on germination percentage, seedling length, antioxidants enzymes activity, Gibberellic acid and Auxin concentration and potassium concentration of maize seedling in stress conditions. At 80 mM Sodium Chloride level, the maximum seedling length was observed in seeds treated with Potassium Nitrate (13 cm). Under severe salinity conditions, with increasing activity of antioxidant enzymes, the lowest malondialdehyde concentration was observed in seeds treated with Potassium Nitrate (0.02 nmol / g fw). Also, priming of maize seed with Potassium Nitrate solution prevented the reduction of gibberellic acid and auxin concentration under salinity stress. In conclusion, seeds which are treated with Potassium Nitrate had the highest corn seedling growth under salinity stress.

The use of growth promoting compounds is one of the possible ways to improve and restore seed quality. This study was conducted as a split plot experiment in a randomized complete block design with three replications in 2019. The main plots consisted of three irrigation intervals (irrigation at 40, 60 and 80% of available moisture depletion) and the subplots was different growth promoting compounds in six levels consisted of control, soil application of humic acid and foliar spray of amino acid, fulvic acid, seaweed extract and the combination of growth stimulants. Results showed that irrigation regime of 80% available moisture depletion decreased germination rate and seed vigor by 11.0% and 28.01% compared to 40% depletion respectively. Increase of irrigation intervals also increased seed electrical conductivity. At the irrigation level of 80% moisture depletion, maximum germination with the means of 87% and 85% was observed in the combination of growth stimulants and spray of amino acids respectively. Growth stimulants improved seedling dry weight. Under irrigation conditions of 60 and 80% moisture depletion, the combination of growth stimulants increased the alpha-amylase activity by 31.03 and 71.42% respectively. On the whole, considering the positive effects of growth promoting compounds on improving and regenerating the seeds of canola they can be recommended in drought stress conditions.

In order to study germination characteristics and early growth of Portulaca oleracea, under different treatment of Walnut (W) and Elderberry (E), Two separate experiments were carried out in a factorial arrangement a Completely randomized with three replications over a farm season (2017). Treatments included Walnut and Elderberry hydro-alcoholic extract in concentrations of 0, 20, 60 and 100%. Results of the analysis of the variance of the laboratory and the greenhouse showed that the Walnut and Elderberry hydro-alcoholic extract had a significant effect on all the characteristics, So that the highest inhibitory effect was observed in 100% Walnut and 100% Elderberry. comparison of the average data from the experimental section showed that with increasing the the Walnut and Elderberry hydro-alcoholic extract in the experimental section germination percentage, germination speed, root length, stem length, fresh and dry weights, and indices of Portulaca oleracea seeds vigor index were reduced compared to witnesses. comparison of the average data from the greenhouse segment showed that with increasing the concentration of the extract stem length, Stem dry weight, Root dry weight, Number of leaves plant, Number of roots in the plant, photosynthesis pigments such as chlorophyll a, b and carotenoids increased significantly and proline increased. Also, the growth of the  roots of the plant has a significant decrease in its meaning. which resulted in a decrease in the dry weight and dry weight of the Portulaca oleracea. according to the results obtained in this study Walnut and Elderberry hydro-alcoholic extract at a concentration of 100% concentration can be used to control Portulaca oleracea.

In order to investigate the genetic variation of seed physiological development in 14 ecotypes of Iranian cumin and one Indian genotype, an experiment was conducted in a completely randomized block design with four replications in the research farm of callege of Aburaihan, University of Tehran. Results analysis of variance showed that ecotypes had significant difference at 5% probability level for characteristics of wet and dry weight of seed at before harvest time and harvest time, seed moisture content before harvest time, maximum germination percentage and rate to 10% of germination, that it indicates the diversity among the 15 ecotypes for these characteristics. Ecotypes did not have significantly different at the 5% level for seed length and embryo size, also the ratio of embryo length to seed length. Factors investigated for germination test included 15 ecotypes and temperatures at three levels (10, 15 and 20 °C). The effect of temperature on germination percentage and rate to 10, 30 and 50% of germination was significant at 5% level and the most percentage and the rate of germination of ecotypes occurred at temperature of 15 °C. Also, the interaction between temperature and ecotype was not significant at 5% level. Among the ecotypes, the "Kooh-banan" ecotype had the highest value for most of the studied characteristics. Therefore, this ecotype is recognized as the best ecotype for characteristics related to germination and it can be used in breeding and farming programs. "Chat" and "Hydarabad" ecotypes had the lowest values for most characteristics.

Arctium lapp < /em>a is an important medical plant with seed dormancy problem. A study was carried out to investigate the effects of seed dormancy breaking treatments on Arctium lapp < /em>a germination. Treatments were arranged in a completely randomized design (CRD) with five replication. The highest germination percentage was recorded in seeds treated with GA3 (500 ppm) +  H2SO4 75% (86%), GA3 (500 ppm) + hot water 70 0C (87%) and GA3 (500 ppm) + hot water 90 0C (84%). Seed scarification with hot water were better than H2SO4 because H2SO4  increased abnormal seedling percentage. Highest abnormal seedling showed in H2SO4 75%, GA3 (500 ppm) + H2SO4 75% and KNO3 (1%) +  H2SO4 75 % treatments (11.7%, 11.3% and 10.9% respectively). Seed treatment with KNO3 andGA3 increas α- amylase activity and Auxin concentration in Arctium lapp < /em>a seedlings and decreased Abscisic Acid content in seedlings. The maximum seedling vigor index obtaines in seeds treated with GA3 (500 ppm) + hot water 70 0C . Results indicated Arctium lapp < /em>a seeds scarification with hot water 70 0C (10 min) followed by socking in GA3 (500 ppm) for 12 hour was most effective treatment for seed dormancy breaking and improved seedling growth.

In order to study effect of seed priming and transplantation on quantitative and qualitative characteristics of sugar beet, an experiment was conducted on a farm land in Naghadeh-Western Azerbaijan at 2018 growing season. The experiment design was split plot based on randomized complete block with four replications. Type of planting method (direct and transplant system) assigned to main plots, and priming (salicylic acid, gibberellic acid, hydroperiming and control (non-priming) assigned to sub plots. The results showed that the effect of planting system was significant on the amount of root sodium, alkalinity, sugar content, coefficient of sugar extraction, shoot dry weight, white sugar yield and molasses sugar content. The effect of priming on all studied traits was significant. Interaction of two treatments was also significant on root potassium, sugar content, white sugar content, sugar extraction coefficient, shoot dry weight, root yield, white sugar yield and molasses sugar content. In this study, the lowest root sodium content (3.02 ppm), root alkalinity (3.09%) were assigned to transplanting system, also the highest chlorophyll index (36.17%) and the least nitrogen (1.92%), alkalinity percentage was recorded for  Hydro priming treatment (3.24%).The results showed that the highest sugar content  (18.17%), white sugar content (16.14%), sugar extraction (88.96%), shoot dry weight (3.64 kg / ha), root yield ( 82.17t/h), sugar yield (14.89 t/ha) and pure sugar yield (12.24%) and lowest root potassium content (2.52 ppm) were allocated to transplanting system with hydropriming treatment.

Seed cleaning is the most important stages of seed processing and according to the type of devices used in the seed cleaning, has significant impact on improving the quality of seed lot and its certification. Therefor this study in order to evaluation of cleaning device effect on germination and vigor of Pishtaz wheat cultivar for comparison with t-test in completely randomized design by 4 replication conducted in Seed and Plant Certification and Registration Institute at Karaj. Treatments included seed before and after processing in 6 lines of seed processing from 5 seed producing company in 3 provinces (Ghazvin, Alborz and Tehran). Also studied characters were percentage of normal and abnormal seedlings, seedling dry weight and length, mobilized seed reserved to seedling ratio, electrical conductivity, content of seedling tissue water, weight percentage of other species seeds, density and weight of thousand seed. Results indicated seed processing were improved and enhanced the quality of seed germination and vigor. Also seed processing lines having gravity separator machines, averagely had more positive impact on improving seed germination and studied traits during processing and therefore application of gravity separator is essential in the processing of wheat seed. On the other hand results revealed processing line having full set of indented cylinder separators suitable for separation undamaged seeds from broken and mechanical damaged seeds for reduce the risk of processed seed lots contamination with mechanical injured and diseased seeds. The results show that manufactory of the processing equipment and adjusting devices according to the seed producing condition have a high importance in archiving to seed improvement and quality promotion.