Due to the importance of medicinal plants, understanding the seed germination response to temperature is agronomically important. A laboratory study was conducted to investigate the effect of different temperatures on seed germination of fennel, cannabis and sesame in a completely randomized design with four replications. Various constant temperatures (5, 10, 15, 20, 25, 30, 35 and 40°C) were considered. According to the results, the effect of temperature on germination rate and percentage in all species was significant. The seeds of fennel were not germinated in 5, 35 and 40 0C and seeds of sesame germinated only in 5 0C. The maximum rate of germination obtained in 30 °C for fennel and 25 °C for sesame and cannabis. The highest germination percentage of fennel and cannabis and sesame were in 20, 25 and 30 0C respectively. The lowest of germination uniformity (GU) were observed in 20 0C for fennel and in 15 0C for cannabis and sesame. Amount of seedling vigor maximized for fennel and cannabis in 250C and for sesame in the 300C. The values of length and weight of radical and plumule were enhanced with the increase of temperature and record on maximum in special temperature and then reduced slowly. The quantitative information provided by this study can be used in prediction of emergence under diverse temperature conditions. Germination of cannabis seeds occurred in a wide range of temperatures and this seed are less sensitive to temperature compared to the other two plants. Germination of fennel seeds was less, except at 200C. The sesame seeds had good germination at 15-35 0C.
In order to study of drought stress and normal irrigation effect on seed germination and seedling vigor of 10 oilseed rape spring genotypes, RGS003, Sarigol, Option 500, RGS006, 19_H, ORS3150-3006, ORS3150-3008, RG4403, RG405/03 and RGAS0324, an experiment was conducted as factorial, based on a completely randomized design with four replications, in the seed analysis laboratory of Seed and Plant Certification and Registration Institution at Karaj during 2013. Results indicated that RG4403 genotype by 3.498 gr. and RGS006 genotype by 3.082 gr had the highest and lowest one thousand seeds weight respectively. Seeds of Sarigol, Option500 and RGS006 genotype, respectively, by normal irrigation and drought stress, had the most primary root, shoot and seedling length and seeds of ORS3150-3008 and RGAS0324 genotypes by normal irrigation respectively had the most primary root and seedling and primary shoot and seedling dry weight. Seeds of Sarigol and RGAS0324 genotypes by normal irrigation had the highest final germination percent. The highest mean germination time, the coefficient of the velocity of germination and mean daily germination, also respectively belonged to seeds of RGS003genotype by drought stress and19-H and RGAS0324 genotypes by normal irrigation. Besides, Sarigol and RGAS0324 had the most length and weight vigor indices. Generally, results showed that drought stress at flowering and maturity duration caused a decrease in seed quality of studied genotypes, but under what conditions, some genotypes like RGS006, 19-H and ORS3150-3006 seed had relatively optimum germination quality and seedling vigor traits.
In order to determinate the cardinal temperatures and investigate the effect of temperature on seed germination and seedling growth of Securigera securidaca, a study was conducted in a completely randomized design with 8 temperature treatments (5, 10, 15, 20, 25, 30, 35 and 40oC) and four replications in research laboratory of faculty of agriculture at the Birjand University in 2013. A two-segmented linear regression model was fitted between germination rate and temperatures to determine cardinal temperatures for germination. Cardinal (minimum, optimum and maximum) temperatures of germination were determined as -1, 22.5 and 40.2oC respectively. Maximum rate and percentage of germination obtained in the range of 20-25oC. Maximum of radicle length and dry weight, maximum of caulicle length and dry weight and maximum of vigor seedling were obtained in 20oC,10-20oC and 5-30oC respectively. Maximum and minimum germination uniformity (GU) was obtained in 25 and 5oC.
The purpose of this study was to evaluate the effect of Nano TiO2 and Nano CNT on some germination indices and growth parameters of some hulled barley cultivars. The experiment was conducted in a laboratory at Shahrekord University during 2014. The study was a factorial, adopting a completely randomized design with four replications. Treatments consisted of titanium dioxide nanoparticles and carbon nanotube (CNT) in four concentrations (0, 10, 30 and 60 mg.l-1) which were applied to seeds of hulled barley cultivars such as Bahman, Makoii and Nosrat. The traits measured were the dry weight of seedling and seedling length, germination percentage, germination rate, mean germination time, the percentage of resistance of radical, seedling vigor length and weight index. The results showed that carbon nanotubes treatments with 60 mg.l-1 had a significant impact on germination percentage, germination rate, seedling vigor length and weight index and seedling dry weight, as compared with other treatments. In this experiment, the highest percentages of resistance of radicle, seedling vigor weight index and seedling dry weight of Nosrat Cultivar were obtained under 60 mg.l-1 carbon nanotube treatment, which was 70, 122.2 and 64.9%, respectively, as compared with control treatment. In addition, 60 mg.l-1 carbon nanotube treatment increased the seedling vigor of Makoii cultivar by 39.8%, as compared with the control treatment. The findings were that in terms of seedling vigor length and weight index, seedling length, seedling dry weight and the percentage of resistance of radical, the Nosrat Cultivar showed better morphological characteristics than Bahman and Makoii cultivars, under laboratory conditions.
Extended abstract
Introduction: Rice (Oryza sativa L.) is one of the most important cereals in the world and the main source of nutrition for more than one-third of the world's population. Compared to other grains, rice is more sensitive to low-temperature stress. Seed priming is a biotechnological tool and a simple, practical, effective, environmentally friendly and cost-effective approach to improve plant tolerance to various environmental stresses and increase seed germination. This study was designed and conducted with the aim of investigating the germination and physiological responses of of rice seeds under different intensities and durations of electromagnetic fields and temperature stress.
Materials and Methods: An experiment was conducted in 2024 as a factorial in a completely randomized design with the variables of electromagnetic field intensity at four levels, and duration at two levels, and temperature stress at three levels on Hashemi rice cultivar, with three replications, at Islamic Azad University, Astara Branch. Rice seeds were treated in a plastic bag under magnetic fields with intensities of (0, 50, 100, and 150 mT), durations of (30 and 60 minutes), and three levels of temperature stress (10, 15, and 25°C). A plastic tray was used for the second experiment and seedling establishment. Healthy seedlings were transferred to plastic pots containing sand. After 25 days, they were used to measure the desired traits.
Results: Results of the analysis of variance showed that magnetic field intensity, temperature stress, duration, and their interactions had significant effects on most of the evaluated traits. Temperature stress led to a significant increase in proline and malondialdehyde contents and a decrease in chlorophyll a and b. The lowest proline (1.017 µmol g⁻¹ fresh weight) and malondialdehyde (4.403 mmol g⁻¹ fresh weight) contents were observed at 25°C without magnetic field exposure. The highest germination percentage (98.95%), radicle length (69.617 mm), chlorophyll a (0.807 mg g⁻¹ fresh weight), and chlorophyll b (0.993 mg g⁻¹ fresh weight) were recorded under the treatment of 100 mT magnetic field at 25°C. Moreover, the highest germination rate (0.560 day⁻¹), shoot length (58.633 mm), seedling length (130.867 mm), radicle dry weight (3.25 mg), shoot dry weight (2.207 mg), seedling dry weight (5.457 mg), length seedling vigor index (13035.55), and weight seedling vigor index (543.528) were obtained at 100 mT, 25°C, and 30 minutes.
Conclusion: The effects of electromagnetic field treatment on germination traits and physiological parameters, including germination percentage, germination rate, and chlorophyll content, were significant, leading to improvements in these indices. The findings suggest the potential application of electromagnetic field treatment as a strategy to enhance seed germination and certain physiological traits under cold stress conditions.
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