نشریه پژوهش های بذر ایران
سال سوم شماره 2 (پیاپی 6، پاییز و زمستان 1395)

The percentage and rate of germination and proper establishment of seedlings are important factors in achieving higher yield per unit area. As an essential element for plant growth and development, Zinc plays a critical role in many metabolic processes, and also has a positive effect on seed germination. In order to determine the effects of seed priming with the concentrations of 0.5, 1 and 2 percent zinc sulfate on the partitioning of reserved materials in seed, starting autotrophic seedling growth and the activity of alpha amylase enzyme in wheat, a factorial experiment was conducted in a research farm of University of Maragheh, Iran in 2014 on the basis of a completely randomized design with four replications. Results showed that zinc priming had a significant effect on all the parameters under study. Mean comparisons showed that an increase in zinc concentration- up to one percent- had a positive effect on the studied parameters, and increasing its concentration more than one percent caused a negative effect on the mentioned parameters. The results of this study showed that the seed dry weight of the control and zinc sulfate (0.5%) treatment reached to a stable level in the days of 21 and 20, respectively. Also in the control and 0.5% zinc sulfate, the total dry weight reached to its initial weight (seed weight) at the days of 15 and 13, respectively. In addition, the growth of autotrophic plant began 10-12 days after of soaking. The seeds treated with 5.0 and 1 percent zinc sulfate had more leaf area than the other treatments; it might happen due to the earlier entrance of the seedlings produced by 5.0 and 1% zinc sulfate treatments to the autotrophic stage as compared to other treatments. The results of variance analysis of the finishing seed's reserved materials, initial kernel, root dry weight and shoot dry weight confirmed that 0.5 and 1% zinc sulfate treatments were better than other concentrations (levels). The treatments of 0.5 and 1% zinc sulfate reached to the autotrophic stage sooner than the control and 2% zinc sulfate treatment. According to the results of this study, 5.0 and 1% zinc sulfate treatments were selected for the field cultivation.

Understanding the germination and emergence patterns of weeds as well as factors which influence on these patterns are beneficial for management programs with respect to weeds. In order to evaluate the effect of temperature, waterlogging and salinity on germination and emergence of common lambsquarters, three separate experiments were conducted based on a completely randomized design with four replications. Results of temperature test revealed the highest germination percentages such as 87, 93 and 88%, obtained in temperature ranging including 15, 20 and 25 °C respectively. Maximum germination rate, radicle length, plumule length, and seedling dry weight recorded at 20°C. Optimum seed vigor index equals to 796.29 observed at 20°C. Germination percentage reduced with increasing waterlogging duration and halted after 8 and 10 days of consecutive waterlogging. Mean comparisons revealed that radicle and plumule length, seedling dry weight and vigour index reduced significantly by increasing the period of waterlogging. Salinity adversely affected germination percentage, germination rate and seedling dry weight of common lambsquarters. These factors were at the highest amount in control and 50 mM NaCl treatments. A downward trend was observed in these factors as NaCl concentrations increased and finally the germination process stopped at concentrations ranged from 300 to 400 mM NaCl. Radicle and plumule length were also reduced from 10.51 and 9.23 cm in control plot to 3.57 and 2.47 cm at 250 mM NaCl. Overall, the results revealed that the Maximum seed vigor index equals to 851.84 was obtained from control treatment and seed vigor halted when the salinity level exceeded to more than 250 mM NaCl. Finally, the results showed that optimum temperature for germination of common lamsquarters was 20 °C and occurrences of salinity and waterlogging stress can decrease growth indices of this weed in germination and seedling stages.

The objective of this research was to evaluate the effect different temperatures on germination and determine cardinal temperatures (base, optimum and maximum) of Secale mountanum at temperatures of 3, 5, 10, 15, 20, 25, 30 and 35 oC. Three nonlinear regression models (segmented, dent-like and beta) was used for quantifying response of germination rate to temperature. Results showed that the different temperatures were effect on germination percentage and germination rate. According to the root mean square of errors (RMSE) of germination time, the coefficient of determination (R2), the simple linear regression coefficients a and b, and the relationship between the observed and the predicted germination rates the best model for determination of cardinal temperatures of Secale mountanum was dent-like and beta models. Base, optimum and maximum temperatures were estimated about 2.70 to 3.17, 21.27 to 30.00 and 35.00 to 35.05°C, respectively with this model. However, due to the above SE for temperature base and negative estimate the base temperature of beta model can be reported the dent-like model. Therefore with used of dent-like model and estimated parameters can be used this model for predicting germination.

A controlled experiment was run to quantify emergence of Kochia indica under different temperature, salinity and seeding depth levels at the Yazd National Salinity Research Center in 2013. Treatments were five day/night temperature regimes: 20/10, 25/15, 30/20, 35/25 and 40/30 °C, five salinity levels: 2, 6, 10, 14 and 18 dS m-1, and seeding depth on the surface (0 mm), 5, 10 and 15 mm. Final emergence percent, emergence rate index and elapsed time (days) to reach 50% of the maximum emergence were measured. Results showed that the highest and lowest final emergence percentage was observed in 25/15 ° C and 40/30 ° C day/night, respectively. Final emergence reduced to 9, 22, 36 and 57% in 6, 10, 14 and 18 dS m-1 compared to 2 dS m-1, respectively. Final emergence was also reduced to 30, 44 and 72% in 5, 10 and 15 mm seeding depths compared to placing seeds on the soil surface. Regression analysis showed that final emergence percentage linearly decreased with increase in salinity and seeding depth levels. In turn, elapsed time (days) to reach 50% of the maximum emergence T50, increased as salinity and seeding depth increased, so that the highest T50 was obtained for 18 dS m-1 and seeding depth of 15 mm. Increase in salinity and seeding depth was associated with a significant decrease in emergence rate index. In addition, using a logistic regression equation, emergence rate of K. indica was quantified at each day after sowing for each temperature-salinity combination to predict the distribution range of the plant in these situations.

This research was conducted to investigate the efficiency of hormonal pretreatment on increasing germination and early growth of seedling, in the seed technology laboratory of Shahed University in 2015 as a factorial experiment based on completely randomized design with 4 replications. The treatments were: 5 levels of IAA (indole-3-acetic acid) include of zero, 0.1, 0.5, 1 and 1.5 mg/L and 5 levels of PBA (Tetra hydro pyranyl ­benzyl­ adenine) include of zero, 0.5, 1, 1.5 and 2 mg/L. Analysis of variance indicated that the use of two hormones or their interactions had a significant effect on all traits such as seed germination, biomass, leaf relative water content and photosynthetic pigments. The highest percentage of germination (66.66%) was obtained in 1.5 mg/L IAA with 1 mg/L PBA. 0.5 mg/L PBA and in 0.1 mg/L IAA the longest shoot (1.28 and 1.17 cm, respectively) was obtained. Germination coefficient decreased about 12.5% by increasing IAA from 0.1 to 1.5 mg/L. The greatest relative water content (42.73% and 37.38%) obtained with 0.5 mg/L PBA and 1.5 mg/L IAA, respectively. Combination of IAA㰐 (0.1 mg/L) on the length of the root and seedling had a positive effect. The high concentrations of PBA and the lowest amount of IAA had similar results of plant biomass. The highest of plant biomass (4.33 mg) was obtained in seed treated with 2 mg/L of cytikinin and 0.1 mg/L of auxin. Photosynthetic pigments were also affected by these two hormones though the IAA was more effective than PBA. It was con­cluded that auxin and cytokinin increases germination and improves the morpho-physiological indicators and thus increase the yield of Stevia.

In order to study the seed germination and dormancy of three weed species (Chenopodium album, Convolvulus arvensis and Setariaviridis) of pistachio orchards in Rafsanjan, Iran, three separate factorial experiments (with 2 factors) were conducted based on a completely randomized design with four replications, at the faculty of agriculture, Vali-E-Asr university of Rafsanjan, Iran, in 2014. Weed seeds were collected from five different regions of Rafsanjan, including Markazi, Anar, Koshkoiyeh, Kabotarkhan and Nogh. Dormancy breaking treatments for Chenopodium album included distilled water (control), KNO3 (at 500 and 1000 ppm), chemical scarification by sulfuric acid (for 5 and 10 min), and cold stratification (for 1, 3 and 5 weeks). Treatments for Convolvulus arvensis included distilled water (control), scarification by sandpaper, chemical scarification by sulfuric acid (20 and 30 min), and boiling water (for 15 and 30 min). Treatments for Setaria viridis included distilled water (control), gibbereilic acid (250, 500 and 1000 ppm), KNO3 (500 and 1000 ppm), and cold stratification (for 1, 3 and 5 weeks). Results showed that seed germination percentage (SGP) and mean germination time (MGT) of three weed species were significantly different among weed populations and dormancy breaking methods. For Chenopodium album, 5 weeks cold stratification resulted in highest SGP (97%) in Nogh population. For Convolvulus arvensis and Setaria viridis, highest SGP obtained after scarification by sandpaper (98% in Kabotarkhan population), and using 1000 ppm gibbereilic acid (60% in Kabotarkhan population), respectively. Also, SGP increased as increasing 1000 seed weight in three weed species.

This study was laid out in order to evaluate the effects of accelerated ageing and natural storage on seed germination and seedling heterotrophic growth of chickpea in Gorgan University of Agricultural Science and Natural Resources in 2014. The experiment was conducted in completely randomized design with four replications. Treatments were 8 ageing levels, such as (2 years, 4 years natural storage, 1, 2, 3, 4, 5 days of accelerated ageing and control). Results showed that the effect of ageing treatment on all traits were significant. Reduction of germination percentage, germination rate, root and shoot length seed vigor index and seedling dry weight in 4 and 5 accelerated ageing days were higher than 2 and 4 natural storage years. Electrical conductivity of seed lots increased by increasing of accelerated ageing to 4 and 5 days that was more than 2 and 4 natural storage years due to non-ability of a membrane to keeping their permeability and refers to higher sensibility of seeds to accelerated ageing. Reduction of the rate and efficiency of reserves used and also reserves dynamic in natural storage was less than 4 and 5 accelerated ageing days, but maximum rate and efficiency of reserves used and also reserves dynamic was obtained at 2 accelerated ageing days because of increasing of repair reaction rates and more activated hydrolytic enzymes in seeds. In final, the results of the present study revealed that chickpea seed damages in 4 and 5 accelerated ageing days was more than 2 and 4 natural storage years that lead to the reduction of germination percentage and rate.

To evaluate the effect of chitosan on seed germination and some biochemical characteristics of the milk thistle herb in conditions of salinity, this experiment was conducted a factorial in a completely randomized design (CRD) with three replications in seed science and technology, Shahed University, Tehran in 2015. Experimental factors were included salinity levels (0, 4, 8 and 12 dS.m-1) and different levels of Chitosan (0, 0.25, 0.5, 0.75 and 1 percent). The results showed that salt stress reduced germination percentage, germination coefficient, germination rate, weight and length vigor index, radical, plumule and seedling length and total biomass and increased mean germination time. Seed priming with chitosan up to 0.5% concentration was increased the amounts of germination coefficient, weighted index vigor and plumule length. The highest amount of total chlorophyll and total protein were obtained in seed priming with 0.5% chitosan levels in zero salinity Level (control). By increasing salinity levels was observed increases in activity of catalase and peroxidase, so that the highest activity of these two enzymes was obtained in the salinity level of 12 dS.m-1 in pre-treated with 0.5% Chitosan. The results showed that seed priming with chitosan 0.5% reduces and improve harmful effects salt stress on some growth traits in seedlings Milk thistle.

The purpose of this study was to evaluate the effect of Nano TiO2 and Nano CNT on some germination indices and growth parameters of some hulled barley cultivars. The experiment was conducted in laboratory at Shahrekord University during 2014. Experiment set as factorial based on a completely randomized design with four replications. Treatments included of titanium dioxide nanoparticles and carbon nanotube (CNT) in four concentrations (0, 10, 30 and 60 mg.l-1) were applied on seeds of hulled barley cultivars including Bahman, Makoii and Nosrat. Traits were included of the dry weight of seedling and seedling length, germination percentage, germination rate, mean germination time, the percentage of resistance of radical, seedling vigor length and weight index. The results showed carbon nanotubes treatments with 60 mg.l-1 had significant impact on germination percentage, germination rate, seedling vigor length and weight index and seedling dry weight compared to other treatments. In this experiment, the highest percentage of resistance of radicle, seedling vigor weight index and seedling dry weight of Nosrat cultivar were obtained under 60 mg.l-1 carbon nanotube treatment with 70, 122.2 and 64.9% compared to control treatment respectively. As well as, 60 mg.l-1 carbon nanotube treatment, increased the seedling vigor of Makoii cultivate 39.8% compared to control treatment. It is concluded that, the Nosrat cultivar based on seedling vigor length and weight index, seedling length, seedling dry weight and the percentage of resistance of radicle showed better morphological characteristics than Bahman and Makoii cultivars, under laboratory experiment.

Roselle is an important medicinal and industrial plant of the family Malvaceae, which is planted in vast areas of Sistan and Baluchestan. In an a laboratory study, the effect of temperature on seed germination of Hibiscus sabdariffa and temperature minimum, optimum and maximum germination, in a completely randomized design with four replications. For this purpose, Temperatures 5, 10, 15, 20, 25, 30, 35, 40, 45 and 50 °C were determined in each treatment. Cardinal temperatures for germination Based on three models Intersected-lines Model, Five-Parameters Beta Model and Quadratic Polynomial Model Respectively. Traits measured where germination percentage, speed of germination and mean germination time, the temperature effect on all traits were significant. The results of the regression analysis of the data showed the best model in relation to the cardinal point of this plant the Five-Parameters Beta Model and according to the results of this model, the optimal temperature for germination of Roselle 4.04°C, the minimum required temperature 29.83° C.

In order to study the effect of zinc and magnesium on agronomic and seed germination traits of wheat (Sivand), the survey implemented from autumn 2012 for two years at the Agricultural Research Station Mahidasht, Kermanshah. The experiment was carried out as factorial based on randomized complete block design with three replications. The treatments consisted of four levels (zero, 20, 40 and 60 kg per hectare in the form of zinc sulfate) and four levels of magnesium (zero, 70, 140 and 210 kg per hectare in the form of magnesium sulfate). The measured parameters included thousand seed weight, hectoliter weight, protein, zinc and magnesium seeds, germination test, growth rate, seed vigor, plant characteristics and grain yield. Results showed the effect of zinc and magnesium factors were significant for most traits at 1 and 5 percent. The effect of zinc sulfate showed that 60 kg zinc sulfate had the best effect on the traits under investigation. The effect of this treatment on two important traits (yield and grain protein percent) with 7.10 tons per hectare and 12.05 percent compared to control treatment was higher about 115 and 103 Percent respectively. Effect of magnesium sulfate levels on the traits showed that the treatment of 210 kg per ha of magnesium sulfate was superior treatments. Mentioned treatment effects on yield and grain protein with 7.84 tons per hectare and 11.89 percent, with 124 and 101.5% was higher than the control treatment, respectively. Considering the amount of field nutrients and wheat require to the elements, the treatments of 20 kg per ha zinc sulfate and 140 kg per ha magnesium sulfate were better than that other treatments and an economically very cost-effective and recommended.

Asafetida (Ferula assa- foetida L.) is an important medicinal plant belongs to Apiaceae family, which has long dormancy. In this research, vernalization, washing time, GA3, medium strength, harvesting time and interaction of these treatments has been studied to optimize condition of germination. Results showed that, vernalization in 4-5°C for two weeks increased 50% of germination compared with control. Maximum and minimum germination was 42% and 20.47% in 6 and 2 hours washing, respectively. Germination of Ferula was increased (41.5%) by using 10 mg/l of GA3 in comparing with control and 25% germination resulted by using half strength MS media. Moreover, mean of germination has been increased by applying these treatments in one years seeds in comparison with fresh ones (61% and 36% respectively). By doing factorial experiments in the CRD, the best-combined treatments could increase germination were combination of vernalization (4-5°C for two weeks), half strength MS media, GA3 (10 mg/l) and washing time (6h).

In order to investigate the effect of pretreatment chitosan biological compounds on seeds of soybean (Glycine max L. cv. Williams) under salt stress conditions, a factorial experiment based on completely randomized design with three replications was conducted at Shahed University in 2015. Factors examined include the combination of chitosan in three levels (0, 0.25 and 0.5 the weight-volume) and salinity at 4 levels (0, 5, 5.7 and 10 dS/m). The results showed that the interaction of chitosan and salinity were significant on seed germination characteristics such as germination percentage, germination rate, mean germination time, normal seedling and physiological characteristics such as proline and soluble sugars of shoots. Pretreatment of chitosan 0.25 percent in contrast to salt stress by increasing 30 percent in the germination rate and increase, 24 and 35 percent proline and soluble sugars of shoot respectively improves seedling germination characteristics of soybeans. Due to the effects of the treatments of chitosan on seed germination and seedling growth of soybean chitosan can be used as a 0.25 percent W/V chitosan treatment in soybeans introduced to faced with conditions that salinity.