نشریه علوم و فناوری بذر ایران
سال دهم شماره 1 (پیاپی 21، بهار 1400)

Replacing biological herbicides instead of chemical herbicides has not only had adverse environmental effects but also has the advantage of biodegradability. In this study, the effect of rye extract in biocompatible polymer chitosan / alginate nanocapsule with non nonocapsulated extract on dodder and purslane were investigated. The experiment was conducted in a completely randomized design with factorial arrangement. Extracts of shoot and root were evaluated at different concentrations (0, 6.25, 12.5, 25, 50 and 100%) on germination percentage, germination rate, radicle and plumule length, radicle and plumule fresh weight. The results showed that the particles were relatively spherical with a smooth surface and the shoot and root extracts had particle sizes of 113 and 350 nm and 71.4 to 129 nm, respectively. Nano-extract of shoot and root reduced germination of sauces seed to zero at concentrations of 25, 50 and 100%. The highest germination percentage of purslane seed belonged to control treatment (78.26%) which was significantly different from other treatments. Shoot and root nano extracts caused complete inhibition of purslane seed germination at concentrations of 25, 50 and 100%, which were significantly different from other treatments. Increasing concentration of rye extract increased the inhibition percentage of studied traits and nanocapsulation increased allelopathic effect of rye extract.

In this research, the effect of cold plasma treatment on the germination characteristics of Camelina sativa, Kelussia odoratissima, and Heracleum persicum seeds were investigated. An experiment based on completely randomized design with in three replications was conducted. The treatments were three cold plasma power of 40, 60 and 80 W applied on the seeds for 2 minutes and untreated sample was also evaluated as control treatment. The measured traits were: germination percentage and rate, plumule and radicle length. The results showed that cold plasma treatment had a significant effect on germination percentage, germination rate, and radicle length. The cold plasma at 80 kV and 2 minutes improved the germination percentage with increasing it by 10.6%, increasing germination rate by 2.35%, and 3.6 centimeters in radicle length in compared with the control sample. Based on the results obtained from K. odoratissima and H. persicum seeds, cold plasma couldn’t break the dormancy of these seeds, despite the improved hydrophilicity and disinfection of the seeds.

Germination of seeds, one of the most critical stages of plant cycle is greatly influenced by drought stress. In this way, the effects of ascorbic acid to improve germination and antioxidant enzyme activities in sheep fescue seeds under drought stress were studied. A factorial experiment based on completely randomized design with three replications was done. None- primed seed (control group) and priming of different concentrations of ascorbic acid (0, 1 and 2 mM) under 0, -0.4, -0.8 and -1.2 MPa drought stress levels were evaluated. The results showed that seed priming with ascorbic acid in different drought levels increased some traits such as germination percentage, vigour index, plumule and radicle length, soluble carbohydrates and protein contents and antioxidant enzymes activities (catalase, superoxide dismutase and ascorbate peroxidase). While it decreased mean germination time, electrical conductivity and malondialdehyde content in comparison to nonprime seeds. So seed priming with 1 and 2 mM of ascorbic acid in -1.2 MPa level increased vigour index, soluble carbohydrates and proteins, respectively by 167.03, 22.26, 35.77, 187.91, 22.61 and 30.20% compared to nonprimed seeds. Also, it increased activity of catalase, superoxide dismutase and ascorbate peroxidase, respectively by 11.85, 22.81, 12.25, 13.83, 31.33 and 9.93% compared to non-primed seeds. Therefore, the use of 1 and 2 mM ascorbic acid concentrations to reduce the negative effects caused by drought stress is recommended.

Aging and salinity stress are main challenges towards of producing a healthy seedling. This research was conducted to investigate the effects of seed aging on the seed germination properties of Wild mustard under salinity stress condition. Experimental treatments were five levels of seed aging 0, 24, 48, 72 and 96 h and different levels of salinity stress 0, 100, 200, 300, 400 and 500 mmol. Seed germination, germination rate and seed vigor were declined at high salinity concentrations. Catalase activity and total seed protein content were decrease due to the aging. Seed protein content (1.4 mg/g fw) declined about 92% and reach to 0.1 mg/g fw after 96h of aging. Catalase activity was decrease due to aging while in contrast, peroxidase activity was higher from 0.04 to 0.11 u/ mg protein after 96 h of aging. It was observed that all fatty acids of wild mustard seed oil were changed at higher aging durations. Behenic acid (C22:0) and Erusic acid (C22:1) were 0.656 and 38.543% in noaged seeds and they increased to 0.751 and 40.186%, respectively.

Seed germination is the first and most sensitive developmental stage in the plant life cycle and the key process in seedling emergence. On the other hand, one of the major barriers to optimum use of medicinal plants outside the natural habitat is limited level of seed germination and seed dormancy. Hence in order to find the best priming and temperature treatment to dormancy breaking and seed germination of medicinal plant seed Pulicaria gnaphalodes (Vent.) Boiss a factorial experiment based on the completely randomized design with four replications and two factors was conducted in Islamic Azad University, Birjand branch in 2017. The first factor of priming type is 11 levels included in potassium nitrate 2% treatment at two times of 24 and 48 hours, gibberellic acid (0, 250 and 500 mg/ l) at two times of 24 and 48 hours, and stratification (7, 14 and 21 days). The second factor was temperature at three levels (15, 20 and 25 °c). The results showed that highest germination rate and percent germination were related to stratification at 7 and 21 days at 25 °c and maximum seedling length, plumule length, radicle length, radicle/plumule length ratio, wet weight of seedling, dry weight of seedling, percent germination, germination rate, longitudinal index seed vigor, weight index seed vigor related to 21 days wet temperature and 15°c. Therefore, 21 days stratification and temperatures of 15 and 25 °c were the best priming and temperature treatments to dormancy breaking and seed germination of medicinal plant seed Pulicaria gnaphalodes.

To study the effect of bio-priming on germination, growth and physiological indices of pumpkin under salinity a factorial experiment in a completely randomized design was conducted in three replications. Experimental treatments were salinity at four levels (zero, 40, 80 and 120 mM) and biological pre-treated at eight levels (control, inoculation with Trichoderma harzianum fungi, Azoto bio-fertilizer, phosphate bio-fertilizer, both bio-fertilizer, combination of fungi and azoto bio-fertilizer, combination of fungi and phosphate bio-fertilizer, fungi and both bio-fertilizer). Phosphate biofertilizer threatment had maximum positive effect on percent germination with increasing the salinity. In combination of fungi and phosphate biofertilizer with increasing the salinity levels reduced fewer the germination coefficient. Low levels of salinity had positive effect on growth indices and caused increase that this indices. Maximum seedling length in different levels of salinity obtained in combination of both biofertilizers treatment. Maximum amount of vigor weighted index obtained in fungi treatment and increasing of salinity level caused that reduced this trait. With increasing of salinity level reduced dry weight of seedling and was maximum amount in fungi treatment. The use of microorganisms caused that reduced the negative effect of salinity. With salinity increasing increased the amount of antioxidant enzymes and the use of biopriming treatments more increased the amount of these enzymes in compared to control which show these treatments was effective in reduction of salinity effect by means of increasing the enzymes. Using of microorganisms with more increasing antioxidant enzymes in compared to control caused reduction of negative effect of salinity stress.

The purpose of this study was to quantification the effect of secondary dormancy inducing on emergence rapeseed using Chapman-Richards model under field conditions. This experiment was carried out using 20 rapeseed genotypes cultivated in Iran under field conditions. Seeds were tested for secondary dormancy according to the Hohenheim standard dormancy test. Seedling emergence trial was carried out using a randomized complete block as a factorial arrangement with four replications in a research farm of Abourahian Campus, University of Tehran for 122 days. Emerged seedlings were removed after counting. The results of this study showed that both genotype and drought stress factors are effective on seedling emergence percentage and rate of rapeseed under field conditions. However, potential secondary dormancy inducing was different among the cultivars, and in Karaj2, H50 and SLM046 genotypes emergence rate before inducing secondary dormancy was 0.407, 0.143 and 0.355 which increased to 0.411, 0.228 and 0.364 after inducing secondary dormancy, respectively. the results of the mean comparison showed that the maximum percentage of emergence in nondormant seed was related to Ahmadi cultivar, but this cultivar was not significantly different with other varieties of Hayola, Moghan, SLM046, RGS003, Opera and Karaj. When secondary dormany induced to seeds, Ahmadi cultivar had the highest percentage of emergence and the lowest percentage of emergence after dormancy inducing was related to Talayeh cultivar.

The purpose of this study was to investigate the effect of seed coating with combinations of micronutrients, stimulants and growth regulators on emergence, plant establishment and early stages of sugar beet growth. This study was carried out in greenhouse conditions at Mohaghegh Ardabili University in 2018. Experiment was conducted as factorial in a completely randomized design with three replications. Seed washing (washing and not-washing), varity (Shekofa-Persian) and various combinations of micronutrients, stimulants and growth regulators which contains 5 were treated with a control (no cover-up) were the experimental factors. Comparison of the mean data from the experiment showed that among the sugar beet monogerm hybrids, Pars hybrid was superior in terms of establishment percentage. The results of this study showed that seed coating after washing increased the efficiency of sugar beet seed coating treatments. Among different treatments, seed coating treatments 1 [Zn+Mn+B (9, 16.5 and 8.5 g/ kg-1 seed Respectively)+ Gibberellic acid+ Ethylene+ Salicylic acid (1.2, 2 and 0.35 mL/ kg-1 seed, Respectively)] and 2 [Zn+Mn+B (9, 16.5 and 8.5 g/ kg-1 seed Respectively)+ Amino acid+ Humic acid + Seaweed extract (8, 12 and 12 g / kg-1 seed, Respectively)] had the most effect on accelerating emergence and improvement of seedling growth and maximum chlorophyll index and quantum yield of photosystem II were observed in these treatments.

Heavy metal stress is one of the most important factors limiting the growth and yield of plants in many parts of the world. The fungus Piriformospora indica, as a mycorrhizal endophytic fungus, stimulates the growth of many plant species and also increases the resistance to biotic and abiotic stress. In this research, the interaction effect of P. indica and Cd on germination of fenugreek, also the interaction effect of P. indica and Cd in soil system were investigated on morphophysiological traits of fenugreek according to a factorial experiment based on completely randomize design (CRD) with 3 replication in two independent experiments. The results of interaction effect of P. indica and Cd on germination of fenugreek showed that Cd stress may give to plants allows germination, but increased in their concentration impaired the some seed germination indices of fenugreek. Also the results of the interaction effect of P. indica and Cd in soil culture showed that Cd stress reduced the most of measured morphological traits mean and increased the most of enzyme studied in fenugreek. According to these results, it seems that the fungus in addition to colonization of fenugreek also has an effect on its improvement in Cd stress.

Glycine max is one of the most important oilseeds plant in all of the word. One of the problems of G. max production is seed deterioration and low germination and vigor during seed storage and before planting time. In order to investigate the effects of seed deterioration on germination and the effects of salicylic acid and ethylene on improvement of deteriorated seed of G. max several experiments were conducted. Accelerated aging test for 0, 6 and 10 days and natural aging test for 6 months were the main effects. After aging conditions, seeds were imbibed with 50 M salicylic acid and 10 M ACC (precursor of ethylene) for 6 hours at 25 °C. Also seeds after natural and accelerated aging test were used without any hormonal treatment as control seed (called dry seed). Germination percentage, electrical conductivity and gene expression of αMY1, βMY1, were investigated on dry seed and under imbibition of water, salicylic acid and ACC for 6, 12 hours using Q-RT-PCR method. Seed germination decreased and electrical conductivity increased with progress of aging. Gene expression varied in different days and different hours. Salicylic acid and ACC had different effects on measured trait. All together aging caused disturbing of seed physiology and salicylic acid and ACC were not able to improve deteriorated soybean seed.