r. tavakkol afshari

The aim of this study was to investigate the relationship between the morphometric characteristics of the seeds of different buckwheat (Fagopyrum esculentum Möench) lots obtained from different planting dates (29th Aug: 1, 13th Sep: 2, 28th Sep: 3 and 12th Oc: 4) with its seed germination quality under different temperature treatments. For each of seed lot, four separate experiments with 11 temperature levels including 4, 7, 10, 15, 20, 25, 30, 35, 37, 40 and 45 °C were carried out in a completely randomized design with 3 replications in seed science and technology laboratory of Agricultural Sciences and Natural Resources of Khuzestan University in 2022. The results of analysis of variance demonstrated that temperature has a significant effect at the level of 1% on germination rate index. According to the model parameters and of course the standard error, the segmented model was chosen as the best model. Based on this, according to the superior (segmented) model, the base, optimal and ceiling temperatures for lot 1 are 4.82, 34.24 and 44.82 degrees Celsius respectively, in lot 2 they are 4.18, 33.82 and 46 respectively. 44.0 degrees Celsius, in lot 3 it was estimated 5, 34.64 and 43.87 degrees Celsius respectively and in lot 4 it was estimated 5, 31.69 and 44.27 degrees Celsius respectively. Identify the cardinal temperatures can be of great help in managing the optimal sowing date of crops.

Camelina (Camelina sativa) is an important oilseed crop from the Brassicaceae family. This plant is important due to its industrial, health and food applications, and the cultivated area of this product is increasing, and important features of this plant. It can be attributed to the low need of this plant for inputs and high resistance to biotic and abiotic stresses. A factorial experiment in the form of a complete block design using SAS statistical software of the seeds of two varieties of Camelina (Sohail and Line 69) in terms of the effect of foliar spraying of micronutrients iron, zinc, manganese and the combined treatment and the control treatment immediately after closing After the formation of 50% of the seeds, foliar spraying was done and it was investigated during 3 repetition. The images prepared from Camelina plant embryos were evaluated and checked and the results of image analysis were compared with the results of the germination . The results of this experiment showed that the seed of line 69, which had the minimum cotyledon length, the minimum embryonic axis length, the minimum seed length and the maximum seed width in the combined foliar spraying treatment, had the minimum ratio of the embryonic axis length to the seed length, the minimum cotyledon length ratio It is related to the seed length and the minimum seed length to width ratio that the smaller size of the seed in line 69 has led to a decrease in the percentage and speed of germination .

The Henbane (Hyoscyamus SPP.) belongs to the potato genus and due to the presence of alkaloids such as atropine, hyoscyamine and scopolamine, it affects the human nervous system. Among the annual and perennial species of this genus, five of them are endemic in Iran. The aim of this study was to determine the cardinal temperatures and evaluate the germination response of five seed ecotypes (Hyoscyamus SPP.) to water temperature and potential. For this purpose, a factorial experiment was conducted in a completely randomized design with four replications. Experimental treatments were run according to eight temperature levels (5, 10, 15, 20, 25, 30, 35, and 40°c) and six water potential levels (0, -0.2, -0.3, -0.4, -0.6 and -0.9 MPa). The results showed that with decreasing water potential, the percentage and germination rate of Ecotypes decreased. Estimation of cardinal temperatures showed that the base temperature and ceiling temperature of the five studied Ecotypes were the same and were equal to 8 and about 40 ° C, respectively. Furthermore, the optimum temperature of these Ecotypes was recorded in the range of 25-35 ° C. The Dashty Ecotype had a wider optimum temperature range. According to R2 and RMSE statistics, the Dent-like model well describes the germination rate response of the studied ecotypes to temperature and water potential.

Phosphorus deficiency and drought stress are limiting factors in wheat yield. Drought stress has different effects on the uptake, utilization and use efficiency of soil phosphorus in wheat cultivars. The purpose of this study is to investigate the response of growth and development, uptake and efficiency of phosphorus in Sirvan and Sivand wheat cultivars at three moisture stress levels of 50, 70 and 95% of soil field capacity (FC) and two phosphorus levels of 0 and 25 mg kg-1. The results showed that addition of phosphorus increased shoot dry weight, phosphorus utilization efficiency, root length and area, and soluble sugars by 42, 61, 84, 47, and 66%, respectively, and decreased electrolyte leakage by 64% under stress conditions of 50%FC. Besides, the phosphorus application of 25 mg kg-1 under drought stress conditions of 50%FC increased the shoot dry weight of the Sirvan variety by 75% compared to the Sivand variety. This increase can be due to the effect of phosphorus on metabolic activities inside the plant, which has led to an increase in root growth, soluble sugar production and cell wall resistance, and a decrease in electrolyte leakage. Therefore, the positive changes observed in different traits and indices due to the use of phosphorus increased the resistance of the Sirvan cultivar compared to Sivand under drought stress conditions. According to the results of phosphorus efficiency and some root morphological and physiobiochemical characteristics, Sirvan cultivar showed a good response to phosphorus fertilizer in modulating the effect of drought stress.

In order to evaluate the effect of temperature, drought and priming on the percentage and rate germination of corn seeds, a factorial experiment based on a completely randomized design with four replicates was conducted. Treatments included eight temperature (5, 10, 15, 20, 25, 30, 35, 40 and 45 ºC), four drought potential (0, -0.4, -0.8 and -1.2 MPa), and five priming (control, hydroprimin, GA priming, ABA priming and, SA ptiming). Both percentage and rate of germination were inhibited at osmotic potentials ≤−0.8 MPa PEG. At 35 ºC temperature. Germination percentage of unprimed seeds was reduced from 94 to 36% in −1.2 MPa. Under these conditions, gibberellic acid hormone treatment improved seed germination. The effect of temperature on germination can be defined in terms of cardinal temperatures. We compared three non-linear regression models (Dent-like, segmented and beta). The outcome revealed that the Dent-like function was suitable for use in describing seed germination response to temperature. The base, optimum 1, optimum 2 and ceiling temperature were estimated to be 9.51, 24.12, 35 and 44.62 °C, respectively. The response of germination rate to both temperature and water potential can be described as a non-linear function of the hydrothermal model. According to the results of this study, hydropriming, gibberellic acid, and salicylic acid increased the mean deviation of the base temperature compared to non-priming treatment, increasing the standard deviation of the base temperature indicates the ability of seed germination in different osmotic potentials.

In many studies, the medicinal properties and impact of plantago ovata on mechanisms of human physical activities has been proven. So that one of the most useful, effective and harmless herbal laxative. drought is one of the limiting factors and a serious danger for the successful production of crops. An experiment was conducted to study germination characteristics of plantago ovata under water and drought stress conditions at different temperatures. The experiment was conducted at the University of Tehran lab, Karaj, in 2015. Temperatures regimes included 5, 10, 15, 20, 25, 30, and 35 °C). For each temperature, the treatment for drought and water stress was four potentials (zero, -4, -8 and -12 bar) with sodium chloride. The effects of drouth stress on seed germination of plantago ovata at different temperatures showed the highest resistance to drought at 20 º C. drouth stress at different temperatures reduced germination parameters nad in the potential -12 germination stopped. Increased temperatures resulted in better conditions for seed germination and increase the drought stress tolerance. Increased severity of drought causes the reduction of temperature range in which the seed can germinate.

In order to study the effect of priming on onion seed germination of Zangan Cultivar in different temperature conditions, this study was carried out with 6 levels of temperature of 5 to 30 ° C and three seed pretreatment, include control, hydro-priming and halo-priming with 0.5% potassium nitrate with three replicate. The results showed that priming treatment with potassium nitrate (0.5%) could be effective on germination components. Primed seeds with potassium nitrate (0.5%) showed more germination at all temperatures. Potassium nitrate (0.5%) treatment also affected the germination reaction to temperature. These seeds showed 33.6% more germination than the other two treatments at 5°c. The results showed that germination percentage at 20°c in all treatments reaches its maximum and then remained relatively constant. In evaluating the segmented model for predicting cardinal temperatures, seed germination at base, optimum and ceiling temperatures was 1.7, 27.38, 46.09°c(in potassium nitrate (0.5%) treatment), 1, 25, 43°c (in hydro-priming treatment) and 1.9, 27.6, 46.12°c (in control treatment). For predicting time of germination at different constant temperatures used Thermal-time that constant coefficient of Thermal-time was 1872.79(°Ch).

Quinoa (Chenepodium quinoa Willd.) is a grain-like crop which has a high grown potential in Iran. Due to it's seed have high nutritional value, therefore, compared to milk nutrition by the FAO. This study aims to determine the seed dormancy and pre-harvest sprouting three cultivars of quinoa. This plant was planted in a randomized complete block design at the research farm of university of Tehran and, phonological traits were recorded. Then the related studies such as seed dormancy and pre-harvest evaluation resistance were conducted in two 15 and 25°C constant temperatures in seed laboratory. The results shown that there is significant genetic variation for pre-harvest sprouting and other traits. The results demonstrate that Titicaca and Santamaria have lowest and highest germination in cluster, respectively. Also, Titicaca cultivar related to the other cultivars have had high percentage of seed dormancy. The results shown that it is possible to handle the quinoa crop in such areas which have frequent risk of PHS.

The aim of this study was to quantify the response of germination rate to temperature and to find cardinal temperatures required for different germination percentiles in Papaver somniferum. Four models of non-linear regression [Quadratic, Segmented, Beta and Dent-like] were evaluated to describe the relationships between germination rate and temperature of P. somniferum over 7 constant temperatures (3, 5, 10, 15, 20, 25 and 30 ˚C). Different statistical indices [Root Mean Squares of Error (RMSE) and coefficient of determination (R2)] were used to compare models performance. The Dent-like was found to be the best model to predict germination rate (RMSE=000.35, R2=0.87). The base, sub optimum, supra optimum and the ceiling temperatures for P.somniferum  seed germination were estimated 3, 7, 20 and 31˚C, respectively. The cardinal temperatures depended on the model used for their estimation. Overall, Dent-like was better suited than the other models to estimate the cardinal temperatures for germination of P. somniferum seed. The highest germination percentage (72) and germination rate (0.86) was observed in 10 and 15 ˚C, respectively.

Seed enhancement methods are applied to eliminate or decrease adverse environmental stress effects and increase seed germination rate and vigor of rangeland plants. The coated seed process is from amplifier ways that stick various materials on the outer surface of the seeds that minimize the negative environmental effects and increase the ability of plant establishment. The aim of this study was to assess the effects of seed coating methods on germination of Triticum aesativum, cultivar Sardariin different moisture stress levels and sowing depths. This experiment was conducted with a completely randomized design with four replications. Treatments of covering material was used in four levels including, non coating levels (NC), mineral-based coating (CC), organic- based coating (OC), and hydro gel-based coating (HC). Moisture treatments were used in three levels of moisture soil content. Two planting depth and three seed diameter including M9%, M14% and M21% were used. During the test, speed of germination was evaluated. The results showed that moisture treatments and planting depth at had highly significant effect and there was no significant effect of coating treatments. Also the interaction between type of covering material and soil moisture was not significant for germination speed, but there was significant difference between treatments of seed size in M9% and M21%. Although in the triple interaction, increasing moisture and planting depth enhanced the speed of germination process, but it was not significant statistically. The seedling growth of covered seed developed significantly, so it can be useful in enhancing plant performance.

In this study the identification of chemical and biochemical characteristics of balangu seed oil (Lallemanthia royleana) and their parameters were investigated under accelerated aging conditions at 24 h, 48 h and 72 h at 41°C and 100% RH in a completely randomized design. The results showed that balangu seed oil content was 19.26%.Fatty acid profiles were 90.71% of unsaturated fatty acids (USFA) and 9.29% of saturated fatty acids (SFA), also the linolenic acid (C18:3), oleic acid (C18:1) and palmitic acid (C16:0) were important of PUSFA, MUSFA and SFA oil seeds, respectively.The antioxidants of oil seeds include 427.8 ppm tocopherols and 210 ml.l-1 of polyphenols. The results showed that 15.2% reduction in oil seed under accelerated aging treatment, also this treatments was the cause of increase of SFA compared to USFA. The oxidation and peroxide production peak was between control and 24 h of accelerated aging treatment. Oil resistance (rancimat) in the 72 h of aging treatment was 1.5 times less than to the control. The germination value (GV) was 1.6, 2.5 and 4.5 higher than the accelerated aging treatments, respectively. In general, it is likely that the changes of chemical and biochemical characteristics of seed oil is happened by oxidative enzymes and this condition is quicker in deteriorated balangu seeds

In order to estimate the germination cardinal temperatures, a laboratory experiment was conducted with Chrysanthemum maximum Ramond in a completely randomized design with four replications. Various constant temperatures (5, 10, 15, 20, 25, 30 and 35ºC) were considered. Germinated seeds were counted each day and the rate of germination and germination percentage was calculated. Cardinal temperatures diagram of Chrysanthemum maximum Ramond seed germination was constructed based on two regression models including segmented model and beta model. The effects of temperatures on rate and percentage of germination were significant. The highest germination rate was in 20º, R50=0.067 (Reverse time to 50% germination). Based on the two regression models, Intersected-lines Model and Quadratic Polynomial Model, the cardinal temperatures of Chrysanthemum maximum Ramond seeds germination (Tbase, Topt and Tmax) were: (1 - 3), (19– 23.1) and (43 – 59) °C, respectively. With increasing temperature, the more suitable conditions in terms of temperature, is created for Chrysanthemum maximum Ramond germination and germination rate is increased

This study was conducted to evaluate the effects of water potential and temperature on seed germination rate of lemon balm (Mellissa officinalis L.). Temperatures used in this experiment had 10 temperature levels including 5, 10, 15, 20, 23, 25, 27, 30, 32 and 35 ° C. At each temperature the effect of salinity levels (0, -0.2, -0.4, -0.6 and -0.8 MPa of Sodium chloride) and the effect of drough levels (0, -0.2, -0.4, -0.6 and -0.8 MPa of Polyethylene glycol) on germination characteristics was studied. This study was conducted in Seed Laboratory, College of Agriculture and Natural Resources, University of Tehran in Karaj in 2015. Data were analyzed using factorial design in a completely randomized design with four replications. The results showed that the effect of temperature and water potential was significant on germination indices. Traits studied were germination percentage, germination rate, root and shoot length and seedling vigor index. The germination percentage and germination rate of lemon balm decreased linearly by increasing salinity and drought stress. In both experiments, the highest (90%) and lowest (20%) germination percentage was observed in control and the potential of -0.8 MPa, respectively. Seedling vigor index decreased by decreasing water potential and increasing in salinity level. Lemon balm seeds did not germinated in 5, 10, 15 and 35 ° C in any moisture levels. The results can be used for future studies on the seed ecology of lemon balm.

In order to investigate and determine the best laboratory test for predicting seedling emergence of canola (Brassica napus L.) in field conditions, two experiments were conducted using three canola cultivars (RG003, Sarigol and Zarfam). In the first experiment, different laboratory tests including standard germination (SG), germination rate (GR), seedling dry weight (SDW), seedling length (SL), accelerated aging (AA) and electrical conductivity (EC) were conducted as a factorial experiment in a completely randomized design with three replications. In the second experiment a randomized complete block design with three replications was used in field conditions. The results indicated that there was not any significant differences between cultivars in terms of SG and GR. Similarly, there was not significant differences between cultivars in terms of SDW, SL and EC after AA for 24 hours at 41 °C. But, GR, EC, SL and SG after AA for 24 and 48 hours at 41 °C showed significant differences among the cultivars. Generally, the results of this study indicated that EC, SG and AA for 24 and 48 at 41 °C can well predict the percentage of canola seedling emergence in field conditions. Therefore, these tests can be suggested for prediction of canola seedling emergence