f. sharifzadeh

In this research, Sesame (Sesamum indicum L var.shevin) seed germination characteristics under drought stress conditions influenced by different seed priming treatments were investigated. In two separate experiments, germination responses to different temperatures (1, 5, 10, 15, 20, 25, 30, 35 and 40 ° C) and also different drought stresses (water potentials of -9, -11, -13 and -15 bar) were considered. Based on the results, 25 ° C was determined as optimum germination temperature. The -11 bar water potential was also determined as drought stress. Hydropriming and osmopriming of the seeds were performed at three temperatures of 20, 25 and 30 ° C. The duration of priming was determined based on the priming temperature and type. Calcium chloride osmopriming treatment was performed in three concentrations of 1, 2 and 3 mM. The seeds were primed using potassium nitrate in three concentrations of 0.1, 0.2 and 0.3%. After priming using the mentioned treatments, the seeds were dried out to initial seed moisture content and then subjected to drought stress (-11 bar) during germination period to determine the best priming treatments. Priming treatments significantly improved seed germination characteristics under drought stress. Overall, The results of this experiment demonstrated that use of hydropriming for the seeds of sesame had the highest germination features. So this treatment can be presented as an appropriate treatment for this plant as it is cost-effective, safe and eco-friendly.

Quinoa has attracted a lot of attention in recent years due to its low ecological needs and rich nutritional value. Therefore, the variability of germination components to temperature and determination of cardinal temperatures were performed by seed germination test at different constant temperatures from -1 to 45°C.The results of the dent-like model showed that the base temperature and ceiling temperature of quinoa were -03.04 and 45.45°C, respectively, and the optimum temperature was from 20 to 35°C. To investigation the effect of salinity and drought stress on germination at 25°C, the seeds were exposed to osmotic potentials from 0 to -28 bar, which were made of sodium chloride (NaCl) and polyethylene glycol (PEG), respectively, to induce stresses. The results showed that the reduction of osmotic potential up to -12 bar was not able to significantly reduce the germination components compared to normal conditions. However, with decreasing osmotic potential to -18 and -24 bar, the germination percentage decreased significantly. The germination was completely stopped at -24 bar of drought-induced, while 24% germination was observed at the same point of the salinity-induced osmotic potential. Therefore, seed germination capacity under salinity-induced stress was more tolerant than drought-induced stress at all levels of osmotic potentials. Most likely, due to the fact that quinoa is halophyte, by absorbing the ionic elements of salt, required for the maintenance of the cell turgor, which concurrent increase in cytosolic osmolality. Thus, this species has a great potential for distribution to other areas such as provinces with dry climate.

In this research, the effect of different seed priming treatments was investigated on seed germination parameters of Securigera securidaca seeds in the low temperature stress conditions. Seeds first were exposed to eight temperature levels (5, 10, 15, 20, 25, 30, 35 and 40 ° C). Experimental treatments included different priming treatments (hydropriming, osmopriming including potassium nitrate and calcium chloride and no priming). The results showed that temperature significantly reduced germination percentage and rate, seedling length and seedling dry weight, normal seedling percentage and seed vigor. 5 mM of calcium chloride treatment at 10 ° C for 20 hours had the highest germination percentage, and 1% of potassium nitrate treatment at 10 ° C for 20 hours had the maximum seedling dry weight and 0.5% of potassium nitrate at 10 ° C for 20 hours and 10 mM of calcium chloride treatments at 15 ° C for 20 hours had the highest percentage of normal seedlings. Hydropriming treatment at 15 ° C for 20 hours had the highest germination rate, seedling length and seed vigor and was also one of the best treatments in terms of normal seedling percentage. So this treatment can be introduced as a suitable treatment for this plant because it is better in most germination traits and it is easier and cheaper to do.

Safflower (Carthamus tinctorius L.) is an important industrial plant, which classified in the category of oil plants. The tolerance of plants to drought is different, as well as Plants have different temperature and water requirements, and understanding this requirement helps them survive and reproduce. Therefore, the purpose of this study was to evaluate the germination characteristics of safflower seeds at different temperatures and humidity and the adaptation power of this plant under these conditions. For this purpose, germination of safflower seed (Faraman cultivar) was investigated in incubator at constant temperatures of 5, 10, 15, 20, 25, 30, 35 and 40 ° C. in this study, 3 regression model including, Beta model, Dent like model and segmented model were used to determine cardinal safflower temperatures. Then, to investigate germination and seedling growth response of Carthamus tinctorius toward different levels of Water Deficite Stress at an optimum temperature, another test was conducted. in this experiment, seed germination was assessed in six levels of Water Deficite Stress with the osmotic potential of 0, -3, - 5, -7 and -9 bar (in temperatures of 20 ° C). Based on Beta model, Dent like model and segmented model, the cardinal temperatures of Carthamus tinctorius seeds germination including, (Tbase, Topt and Tmax) were: (4.6, 4.1, 4.1), (22.02, 20 – 24.3, 22.5) and (43.3, 50.3, 50.3) °C, respectively.

Bio-priming and application of bio-fertilizer has special importance in crop production and sustainable soil fertility. Growth and quality improvement with environment-friendly microorganism have been proved in crops. In order to evaluation of bio-priming possibility in seed improvement of sugar beet cultivars, effects of two bacteria species including Pseudomonas fluorescens and Pseudomonas putida on seed germination and growth indices were evaluated. Experiment was directed as factorial in randomized complete block design with four replication, there in experimental factors were bacteria species including Pseudomonas fluorescens, Pseudomonas putida and no bacteria as control for first factor, and beet cultivars including Pars, Torbat and line 31782 as second factor. Germination percentage affected with cultivar, bio-priming and their interaction, but germination rate was only affected by bio-priming. The highest germination percentage and was related to Pseudomonas putida and Pars cultivar. Application of bacteria increased germination rate versus control. Other mean comparison showed that Pseudomonas fluorescens increased root length, shoot length and seedling length and Pars and Torbat cultivars has more root and shoot length rather than Line 31782. Bio-prime with Pseudomonas fluorescens and Pseudomonas putida enhanced Vigor Index I, but Vigor Index II was only affected by cultivar. Pars and Torbat cultivar had higher germination traits and Vigor Index I and II to Line 31782 and showed more reactions to treatments. Generally, Bio-primingtreatments affected sugar beet cultivars versus control. Both bacterial strain act identically but Pseudomonas putida had more effects on cv. Pars.

Seed dormancy has a critical role in ecological adaptation of wild plant species such as Hordeum spontaneum، a wild relative of barley. In this study، 192 ecotypes of Hordeum spontaneum maintained in National Plant Gene Bank of Iran (NPGBI) originating from different climatic zones of the country were evaluated. Morphological، phenological and physiological traits were recorded in the field. After harvest، the seeds were kept at 5°C for six months then were evaluated for seed dormancy. Evaluation of seed dormancy in different ecotypes of wild barley indicated that، seed dormancy was significantly higher in ecotypes of desert and cold desert climates (77. 6% and 83. 7% respectively) compared to ecotypes originating from cold steppe climates (45. 6%). The germination index was higher in cold steppe ecotypes (2. 08) than ecolypes of other climates. Correlation of seed dormancy and some qualitative traits such as glum color، grain color and awn color was significant. In this study the seed dormancy was higher in ecotypes with darker color glum، grain and awn.

Field observations suggested that French psyllium (Plantago psyllium) probably exerts allelopathic effects, although there was no evidence in the literature to support this assumption. The main objectives of this study were to determine whether P. psyllium affects the germination and growth of some weeds by allelopathic function. To explore allelopathic responses of P. psyllium upon germination and growth stages of redroot pigweed (Amaranthus retroflexus ), wild barley (Hordeum leporinum), black mustard (Brassica nigra), Lambsquarters (Chenopodioum album L.), a laboratory bioassay and three greenhouse experiments including root and above ground residues of P. psyllium effects and simultaneous growth of P. psyllium with weeds on target plants were conducted. Results showed that aqueous shoot extract, shoot residue and simultaneous growth of P. psyllium displayed the most consistent negative effects on germination and dry matter of target plants, respectively. Shoot residue and simultaneous growth significantly decreased height and dry matter of all target species except for wild barley. On the other hand, there were no significant effects of root residue of Corresponence to: Asghar Rahimi, Rahimiasg@yahoo.com A.Rahimi et al 14 P.psyllium on dry matter and height of target plants. Results also showed that P. psyllium can decrease the ability of weeds to germinate, grow and survive especially in drought-prone environments and where water resources are limited.