نشریه علوم و تحقیقات بذر ایران
سال پنجم شماره 1 (بهار 1397)

Germination and seedling growth under salt stress is important for establishment of plant. Hence recognition varieties of plants that have rapid and uniform germination under saline conditions can help to the early establishment and seedling growth. In order to evaluate seed soaking effect in nanofertilizers on germination charactristics and seedling growth of wheat cultivars under salt stress with nano-fertilizers was performed experiment in 3-factor factorial in a randomized complete design in three replications with four wheat cultivars (Sivand, Parsi, Pishtaz and Chamran2), salinity stress with Nacl (Merck, Germany) in different concentrations (4, 6, 8 and 10 ds/m) and three types of supplement nano-fertilizers (nano-phosphorus, nano-potassium and nano-microelements), under controlled conditions, The results showed that four wheat cultivars reaction compare to apply of salinity levels and types of nano fertilizers was significant for studied characteristics (rate and percentage of germination, seedling length, dry weight and vigor index). So that treatments interaction Parsi cultivar, nano-phosphorus fertilizer and salinity stress 4 ds/m was highest, while interaction in Chamran2, nano-potassium fertilizer in salinity of 10 ds/m among treatments was lowest. So it seems the higher concentration of salt and with increasing salinity levels, even priming different types of nano-fertilizers couldn't be able to improve studied characteristics, generally, at lower concentrations of salt, Nano-fertilizer treatments has moderated somewhat negative effect of salt, but in higher concentrations it has no effect, Except germination rate parameter that even in conditions of salinity up to 10 ds/m could also be effective and increase the germination rate.

Nowadays, hydro-priming has been known as a simple and inexpensive way for improving the efficiency of the seed. To evaluate the effects of seed vigor of two canola cultivars on the hydro-priming effectiveness, a factorial experiment was conducted based on randomized complete design, with four replications. Experimental factors included two cultivars of rapeseed (Okapi and Opera), three levels of seed vigor (control, 2 and 4 days aging) and pre-treatment (non-priming and hydro-priming). With decreasing the seed vigor level, Germination and seedling growth indices of Opera was further declined. On the other hand, the more promotive effects of hydro-priming were found on seed germination percentage and germination rate and seedling dry weight of the Okapi. In the third level of seed vigor, the positive effects of hydro-priming on germination and seedling growth indices were significantly reduced. Increasing amount of the soluble sugars and decrease of the total protein content and catalase activity in deteriorated canola seeds occurred. Hydro-priming partly eliminated adverse effects of seed deterioration. So that highest soluble sugars (2.82) and the lowest total protein (1.08) and catalase activity (0.021) were observed in seedlings produced from more deteriorated non-primed seed lot. Finally, according to the results of this study, it can be mentioned that priming is useful at least in relation with repair of injuries induced by seed deterioration.

Achillea wilhelmsii is one of the forage and medicinal plant in Iran. This plant is in danger, because of illegal collecting from wild resources for medicinal and hygienic uses. The objective of this study was to establish the effects of pre-chilling on germination treats in 23 populations of Achillea wilhelmsii. The seeds were collected from different provinces. This study was conducted by factorial based on completely randomized design. The results of analysis of variance showed that the effect of population×treatment on A. wilhelmsii seeds germination treats were highly significant different (p<0.01). Comparison of mean of germination treats on control and pre-chilling conditions showed that the pre-chilling increase the mean of rate of germination, length of plumule and decrease length of radicle and ratio of radicle to plumule, but no effect on percent of germination, length of seedling and vigor index of seed. The most of value of rate of germination was found in populations, 9820 (Kordestan-Divandareh) and 9961(Kordestan-Sanandaj) on pre-chilling condition and the most of percent of germination was found in populations 9820 (Kordestan- Divandareh) and 19489 (Kordestan-Baneh) on pre-chilling and control condition respectively. The population 9961 (Kordestan-Sanandaj) had the most of value of length of radicle, length of seedling, vigor index of seed on control and most of value of length of plumule on pre-chilling condition. So, pre-chilling increase rate of germination and no effect on germination percent of seeds, length of seedling and vigor index of seed of Achillea wilhelmsii.

This research was done to evaluate the ability of standard germination test to predict emergence and establishment of barley seedlings in farm. The experiment was conducted under both laboratory and farm conditions at Razi University during 2013-14. In laboratory, eight seed lots of dryland barley were compared in a standard germination test based on completely randomized design and different indices related to seed and seedling vigor were measured. These seed lots were also planted under farm condition as a randomized complete block design and percentage and rate of seedling emergence were evaluated. The results of laboratory test showed that the seed lots were significantly different in final germination percentage, normal seedlings percentage, daily germination rate, root length, root dry weight, shoot dry weight and seedling vigor index. Orthogonal comparisons of data from the laboratory and the farm experiments showed that the new seed lots had higher germination and vigor characteristics than the old seed lots. In the correlation analysis between the measured traits in the farm with the laboratory conditions showed that the percentage and rate of seedling emergence in the farm test had higher correlations with final germination percentage, normal seedling percentage and daily germination rate in the laboratory test. So, it seems that we can recommend standard germination test with high trust to predict the seedling emergence and establishment of dryland barley in the farm.

In order to recognize effects of chemical and mechanical treatments on some of the most important features of seed germination of Myagrum, an experiment was conducted based on completely randomized design with four replications at Razi University. The experiment treatments were distilled water (control), sulfuric acid (98% for 2, 3 and 4 minutes), potassium nitrate (3%for 3, 4 and 7 days), hydrogen peroxide (30% for 2, 3 and 4 minutes) and scarification with sandpaper and prechilling (for 1, 2 and 3 weeks). Germination percent, germination rate, length and dry weight of epicotyl, length and dry weight of radicle, seedling total dry weight and vigor index were evaluated for Myagrum seed. Results showed that the most germination percent was related to hydrogen peroxide treatment for3 minutes (91 %) and scarification with a chilling for 3 weeks (84 %) and the lowest germination percent was observed in sulfuric acid treatment. The results of treatment group comparisons also showed that using hydrogen peroxide had the greatest impact on seed germination of Myagrum. The most germination rate (4.5) and epicotyl dry weight (1.6 g) was observed in hydrogen peroxide for 3 minutes. The most epicotyl length (22.7 mm), radicle length (36.6 mm), radicle dry weight (1.1 g), seedling dry weight (2.5 gr) and vigor index (49.9) were related to seed scarification along with chilling for 3 weeks. Our results also indicted that application of sulfuric acid due to extreme damage onembryo leaded to death of Myagrum seed. It seems that lack of appropriate germination in Myagrum seed could be due to embryo physiological factors because all evaluated treatments had more impact on seed metabolic and harmonic processes.

In order to investigate the effect of accelerated ageing and priming on biochemical and germination indices of cumin, a two factors experiment was conducted based on completely random design with four replications. Experimental factors were included seed deterioration in four levels (control, 12, 24, 36 hours) and priming in five levels (urea and KH2PO4 in two Osmotic potentials of -1 and -1.5 Mpa, and hydro-priming with distilled water). The highest catalase and ascorbate peroxidase activities as well as soluble protein content were observed in the non-deteriorated seeds primed with KH2PO4 -1.5 Mpa. Also that the highest germination percentage (86%) and germination rate (2.34 seed day-1), seedling length vigor index (4.90) and the lowest mean germination time (8.4 day) related to the nondeteriorated seeds primed with KH2PO4 -1.5 Mpa. The biggest shoot (3.52cm) and root (2.32cm) length attained from not deteriorate seeds that primed with urea -1.5 Mpa. Generally, the results showed that priming by KH2PO4 with osmotic potential of -1.5 Mpa could improve vigor of
deteriorated seed of cumin.

The effects of priming with different concentrations of indole-3-acetic acid (IAA) on physiological characteristics of three cotton cultivars (Sahel, Golestan and Varamin) as well as their effects on controlling of damping-off caused by Rhizoctonia solani were investigated in two separate experiments. To determine the effects of IAA on seed germination, IAA was used at 0, 0.1, 0.01 and 0.001 μM in plastic petri dishes. In the second experiment seeds treated with 0, 0.1, 0.01, and 0.001 μM IAA grown in infested soil with R. solani inoculum. Shoot and root growth and fresh weight were evaluated 28 days after sowing and the total phenolic content of the root extract was determined by the Folin–Ciocalteu method. The results showed that seed germination, growth of shoots, roots and fresh weight increased significantly by the application of a low concentration of IAA (0.01 and 0.001 μM). The application of 0.01 and 0.001 μM of IAA also reduced disease index caused by R. solani, 17% and 38% in Sahel and 1% and 33.5% in Golestan and Varamin, respectively. The concentrations enhanced total phenolic content in defence system. Primed seeds showed a significant effect on some physiological characteristics and disease index in three different cultivars.

Halopriming involves pre-sowing soaking of seeds in salt solutions, which enhances germination and seedling emergence uniformity under adverse environmental conditions. An experiment was conducted to evaluate the effects of halopriming on the germination, malondialdehyde concentration and some hormones contents of wheat seeds under salinity stress. The experimental design was three factors factorial arranged in a completely randomized design (CRD), with four replications. The first factor was salinity stress (0 and 100 mmol NaCl solution), the second factor was priming concentration (1, 2 and 3% concentration of KNO3) and third factor was two wheat cultivars including Niknijad (salt tolerance) and Qods (salt sensitive). Remarkable decreases were observed in seed germination, seedling lenght, α-amylase activity and GA3 content of both wheat cultivars, especially in Qods under salinity stress condition. Wheat seed piming with KNO3 increased seed germination, antioxidants enzymes activities, α-amylase activity, GA3 concentration and reduced lipid peroxidation and ABA compared with other priming treatments in both wheat cultivars. Under salinity condition maximum Niknejad seed germination was observed in seeds primed with 2% and 3% KNO3 solutions (87.1% and 87.9 % respectively) and maximum seed germination in Qods seedling obtained in seed treated with 3% KNO3 solutions (75%). All KNO3 seed priming treatments decreased ABA content in Niknejad seeling but Qods seed priming with 2% ans 3% KNO3 solutions decreased ABA content compared non-primed seeds (113 and 101 μg g-1 respectively). Seed priming improved cell membrane stability in both wheat cultivars and the lowest malondialdehyde concentration under salinity stress obtained from seeds primed with 2% ans 3% KNO3 solutions in both wheat cultivars. In conclusion, KNO3 seed priming appears to be an appropriate treatment to improve wheat emergence and overall seedling establishment under salinity conditions.

This experiment was conducted to effect of changes in planting date and moisture content on vigor, protein and starch contents also seed health of corn (var sc704). Experiment was done in field of agricultural and natural resources research center in Ardebil province (Moghan) as randomized complet block in three replications Treats included: three levels of planting dates (10-May, 25- May and 9-june), four levels of seed moisture content at harvest time (30%, 25% and 15%). When cobs reached to desired moisture were air dried for getting 14% moisture content. Then the kernels were separated by laboratory sheller and graded to three sizes flat (7mm), round (6mm) and medium (5.5mm) by three sieves. Measured traits included: blotter test, standard germination, mean time to germination, radicle emergence, seed starch and protein contents. Delay in planting and harvesting caused to reduce in starch and protein content significantly. The highest fusarium infection percentage belonged to produced seeds in the third planting date when harvested with 15% moisture content and the lowest rate belonged to the first planting date 25% harvest moisture content. Delay in planting caused to reduced seed quality and low seed quality was highlighted in delayed harvest. Also the rate of decreasing in round seeds was more than flat and medium seeds so that the second planting date and 15% harvest moisture, resulting in a reduction of about 14 percent in normal seedlings in round seeds. The minimum percentage of germination and vigor were seen in round seeds that produced at the third planting date and harvested by 15% moisture content.

In order to study the effect of Azotobacter chroococcum, Azospirillum lipoferum and Pseudomonas fluorescen application on late maturity Maize (Zea mays L.) single cross hybrids (SC700, SC 704 and a promising single cross, B73×K18) seed germination ability and seedling vigor a laboratory research was conducted. Experiment treatments including hybrids seeds were single inoculated with one by one bacteria and co inoculated by two and three bacterial combined inoculants and no inoculation as control treatment. Also studied characters including: final germination percent, mean time to germination, mean daily germination, coefficient of velocity of germination, daily germination speed, seedling, primary root and shoot length, seedling, primary root and shoot dry matter and seedling vigor index were determined. Results revealed that except of mean daily germination and coefficient of velocity of germination, other studied traits affected by interactions of hybrids and Plant Growth Promoting Rhizobacteria. Likewise, revealed that application of an inoculants of three bacteria combination have highest growth promoting effect on germination ability and traits related to seedling vigor of all hybrieds and Azotobacter chroococcum and Pseudomonas fluorescens and seed single inoculation by those bacteria have most growth promoting effect respectively. Also, revealed that studied characters of SC704more than other hybrids affected by growth promoting effect of studied bacteria and respectively B73×K18 and SC700 affected by studied Plant Growth Promoting Rhizobacteria stimulating effect and studied characters have high correlation among them. Therefore, based on this research results application of studied Plant Growth Promoting Rhizobacteria have considerable effect on Maize studied hybrids seed seedling enhancement.