نشریه علوم و تحقیقات بذر ایران
سال چهارم شماره 1 (بهار 1396)

One of the parameters for obtaining high yield per unit area, is the of the rate and percent of germination and establishment of seedlings of planted seeds. Priming is one of the techniques that results in increased percent and rate of germination and emergence. To do this, response of wheat to priming and nitrogen were evaluated. In order to evaluate the response of wheat to seed priming and nitrogen  a factorial experiment was conducted arranged in an RCBD with three replications on Golcheshmeh farm (Golestan proviance) in 2015. seed priming at five levels i.e. (non-primed and primed seeds with (hydro priming, with 0.03% zinc sulfate, 2%potassium chloride (KCl) and 2% potassium nitrate (KNO3), and nitrogen as the second factor consisted of three levels: nitrogen fertilizer (from urea): 1- No nitrogen fertilizer, 2- 75 Kg.ha-1, 3- 150 Kg.ha-1, The effect of priming and nitrogen fertilizers on yield and its components were highly significant. Grain yield and its components increased with zinc sulphate priming and they increased with an increase in nitrogen level. Grain yield Increased from 4464.64 to 5830/30 kg ha-1 with priming with zinc sulfate. As well, Grain yield Increased from 3810 to 5642 kg ha-1 with Nitrogen fertilizer (150 Kg.ha-1) ).The effect of priming by nitrogen interaction was not significant on any of the traits.

This study aimed to evaluate the effect of seed priming with plant growth promoting rhizobacteria (PGPR) on germination components of flaxseed under salinity conditions a factorial experiment was conducted a completely randomized design (CRD) with three replications in the Seed Science and Technology laboratory of Shahed University in 2014. Experimental factors consisted of five levels salinity stress, zero as a control, 2.5, 5, 7.5 and 10 dS.m-1 and pre-treatment with PGPR in five levels, no priming as a control, Azotobacter (strain Azeto-5), Pseudomonas fluorescent (strain P-169), Pseudomonas putida (strain P-168) and biological phosphorus fertilized 2. Results showed that the high mean allometric (1.31) corresponds to a salinity of 10 dS.m-1. The interaction of priming with biological phosphorus fertilized 2 and salinity of 2.5 dS.m-1 led to the highest average length of seedling vigor index (1375.83), root length (6.83 cm) and seedling length (14 cm).The highest mean time to germination (2.15), weight seedling vigor index (1.87) and dry weight (0.019 g) was conducted to priming with Pseudomonas fluorescent in salinity of 10 dS.m-1. Non-priming (control) in zero levels of salinity (control) also has the highest mean germination rate (15.33 seeds per day).The use of biological phosphorus fertilized 2 and Pseudomonas fluorescent is effective on modified germination index of flaxseed  especially increased seedling growth and seed vigor in salinity stress.

In order to evaluate the effect of priming on seed germination of coneflower at different times and temperature under salinity stress an experiment conducted factorialy as completely randomized design with 3 replications. The seeds were primed with potassium nitrate 5% at for four times (control, 10, 20 and 30 h) and four temperature (control, 4, 10 and 20 ° C), then the primed and unprimed seeds were subjected to two levels of salinity (0, 5 bar) as induced by sodium chloride .Results showed that effect of the treatments on evaluated traits was significant. Seed priming for 20 hours at 20 ° C increased percentage and uniformity of germination, seedling length and dry weight and reduce the mean germination time. It was found that pre-treatment for 20 hours at 20 ° C improves germination characteristics under salinity stress.

In order to evaluate cyperus rotundus resistance to heavy metals stress, copper, nickel and cobalt, in the germination stage, the experiment was conducted in factorial based on completely randomized design with three replications in agronomy and horticulture laboratory of Jiroft University. The first factor consists of three metal copper, nickel, cobalt and the second factor levels consists of metal concentrations (0, 200, 400, 600, 800, 1000 ppm), respectively. The results showed that germination percentage, rate and mean germination time were affected significantly (p <0.01) affected by heavy metals and levels of stress and only, germination percentage were affected by their interactions. The effect of stress levels showed that treatments of 200, 400, 600, 800 and 1000 ppm, compared to control the tubers germination rate decreased tubers 17.8%, 26.07%, 35.7%, 46.4% and 57.1%, respectively. These treatments decreased tubers germination percentage respectively 9.2%, 14.9%, 24.1%, 36.7% and 45.9% compared to the control. The lowest germination percentage (70.5) and rate (1.7) happened in nickel stress. The Regression analysis results showed that germination rate changes affect the stress levels of copper, nickel and cobalt fit on quadratic function with R- square (R2) above 90%, which was statistically significant at 0.01. In general, the results of this experiment showed cyperus rotundus is tolerance to heavy metals stress so that, even able to germination and growth at concentrations up to 1000 mg/L, also tolerance Capability cyperus rotundus to copper heavy metal was higher than cobalt and nickel i.e. Cu >Co >Ni.

In order to evaluate low temperature stress and the production on germination characteristics, growth parameters and photosynthetic pigments Maxima corn, experiments using as factorial a completely randomized design with three replications was conducted at Seed Science and Technology Laboratory of Faculty Agricultural Sciences, of Shahed University in 2014. Factors examined include Two of hybrid maize production MV 524 Maxima (production Iran and Hungary) and cold stress in five levels (control (no stress), zero, 2, 4 and 6 °C per Which for 2 hours in distilled water) were considered. The measured traits include germination percentage, percentage of normal seedlings, root length and shoot and seedling, relative water content, average time of germination, germination rate, chlorophyll a, band total, carotenoids and anthocyanin. The results showed that cold stress and germination of seed production and normal seedling was significant at 5% level. The production, cold stress and their interaction were significant for the percentage of photosynthetic pigments. Mean comparison showed that the highest and lowest percentage of germination was achieved in seed production and seed production in Hungary. Most of chlorophyll a, chlorophyll b, total chlorophyll and carotenoid related to a temperature of 4°Cand maximum temperature of 2°C is the anthocyanin. The results it was concluded that control treatment (no stress) has the highest percentage of germination, seedling percentage normal and Mean germination.

This study was carried out in Manesht and Qalarang protected area in Ilam province to study the flora of vegetation and soil seed bank. The study of vegetation was carried out with releve method and the soil seed bank was estimated using the seedling emergence method. In total, 192 plant species belonging to 38 families and 131 genera were identified, of which 67 species were common in both seed bank and vegetation and 13 and 112 were found only in the seed bank or in the vegetation, respectively. The vegetation of the study area was represented by 179 species, belonging to 125 genera and 36 families. The Asteraceae and Poaceae were the most dominant families in terms of number of species. The soil seed bank included fewer taxa: 80 species belonging to 63 genera and 26 families, respectively. The Asteraceae, Boraginaceae and Papilionaceae were the most dominant families in terms of number of species in the soil seed bank. The dominant life form in the soil seed bank and vegetation were Therophytes (42 %) and Hemicryptophytes (48 %) respectively. From the chorological point of view in both the soil seed bank and vegetation the largest proportion of the flora belongs to the Irano-Turanian (68.7 %) elements. The dominant growth forms in the soil seed bank included herbaceous annual (40 %), herbaceous perennial (32.5 %) and in the above-ground vegetation included herbaceous perennial (48.6 %) and herbaceous annual (25.1 %).

In order to study the effect of priming on the germination and growth parameters of vetch seedling under the salinity stress, an experiment was carried out in seed Technology Laboratory of Ramin's Natural Resources and Agriculture University, Khuzestan. The experiment was carried with three replications. The salinity treatments were applied in four levels: o (Control), 6,12 and 18 DS/m by levels of priming of different resources including gibberellic acid (25 mg/kg), calcium carbonate (20g/L), salicylic acid (25 mg/kg), polyethylene glycol (15 times), water(PH=8.04, EC=2.41), distillated water and control (without priming). The results showed that the different levels of salinity lead to decrease the seed germination and seedling growth parameters in all primed and non-primed seeds. Moreover, the priming caused to improve the germination in all levels of salinity compared to control group (without priming). Among these, the prime of calcium carbonate had a positive role in reducing the effect of salinity stress on the parameters such as seed germination and seedling growth so that the primed seeds by calcium carbonate had less reduction in above-mentioned parameters than other primed seeds

The research aimed to study the genetic diversity of 26 rice genotypes in 2013 at the Research Center for Agriculture and Natural Resources Khuzestan province factorial experiment in basis completely randomized design with 3 replications of 24 lines and 2 hybrid as the first factor and salinity stress with NaCl at 4 levels of zero (distilled water), 4, 8 and 12 mmoh/cm as the second factor was implemented. Traits of germination percent, mean germination time, germination rate, radicle length, plumule length, seedling length, ratio of radicle length to plumule, wet weight of seedling, dry weight of seedling, ratio of dry weight to wet and index seed vigor were studied. The principal components analysis, 11 studied traits is divided into 2 components on the basis of 64% of the data changes can be justified. Using cluster analysis were 26 genotypes in three clusters. Lines 15, 19, 20, 48 and 53, according to the results of cluster analysis and biplot rate germination, plumule length, radicle length, seedling length, weight and vigor index lower were. The third cluster lines do not have the tolerance to salinity. Lines 2, 4, 7, 10, 13, 16, 21, 23, 25, 28, 31, 34, 35, 36, 41, 42, 44, 55, with hybrids and Hb2 in the cluster were Hb1 according to principal component analysis and biplot half are salt tolerant. Line 40 was alone in the cluster according to the results of cluster analysis and biplot all traits germination, plumule length, radicle length, seedling length, radicle to plumule ratio, wet weight, dry weight, dry weight and seed vigor was higher than the overall mean and so is salt tolerant.

This study aimed to investigate the changes in the soil seed banks density and species Number  in various stages of succession (plowing land and leaving) and aimed to investigate the similarity between above ground vegetation and soil seed bank in the semi-steppe rangelands in Karsanak located. In winter of 2012, the key succession areas (3-5, 15-10 and >25 years and a control area (pasture)) were selected and soil samples were collected from two depths 0-5 and 5-10 cm in 5 plot established along transects based on systematic random method. Above ground vegetation was also studied and recorded in the next growth season, (2013) in each plot. General Linear Model was applied to compare the species density and species Number  of the soil seed bank and in the succession series (plowing). Indicator Species Analysis (ISA) was used to determine the index species in the each steps of the sequence. Detrended Corespondance Analaysis (DCA) was used for separating the species groups of the each step. The results showed that the various stages of succession have significantly effects on the soil seed banks density and species Number. Results of DCA analysis and ISA analysis revealed that classification of plant communities on the basis of the above ground vegetation dataset led to forming distinguishable and separate groups whereas the soil seed bank dataset, since it was generally composed of pioneer plant species, could not display distinct plant communities.

Seed processing is one of the most important step in wheat production cycle and more than 12 percent of wheat seed lose annually in harvesting, transportation and processing factories. More than half of seed losses occurred in the factories that can be reduced by consider some technical comments. In this paper, operational process and critical point of wheat seed process analyzed in Thehran, Alborz and Ghazvin provinces using the cause and effect diagram and matrix. Besides, the effective parameters on wheat seed losses were studied. Result of filed study showed that averagely 15 percent of wheat seed lost in harvesting, transportation and processing factories in Thehran, Alborz and Ghazvin provinces. Although, Physical purity and germination of final seed were 98 percent and 88 percent respectively, but the seed losses was considerable in reject fraction of some process steps. It occurred especially in second indented cylinder and gravity table (up to 90 perecent). Over feeding, unsuitable adjustment and lack of technical knowledge determined as effective parameters on wheat seed losses. Besides, some of seed processing machinery was old (about 20 years) and increased seed loss in compared whit new one. So, revision of seed pricing and standardization of seed processing can be suggested at the national level.