عنوان مقاله [English]
Germination, growth, yield and quality of crops are determined by seed material, which can be improved by pre-planting treatments with the participation of various physical factors including electric field, magnetic field, laser radiation and microwave radiation. Stimulation before sowing seeds with a magnetic field includes a constant magnetic field generated by permanent magnets and electromagnets, as well as a variable magnetic field. The variable magnetic field is generated by specially designed electromagnets. The biological behavior of seeds, roots, pollen grains and buds of some plants changes under electromagnetic fields. For this reason, studies have been conducted on the side effects of this field on the germination response and seedling growth and yield in some plants. Plant cells have a negative charge that can absorb positively charged ions. Cytochemical studies have shown that root cells exposed to a weak magnetic field compared to control cells show a state of calcium saturation in the cytoplasm of all their organs. Magnetic fields affect both the activity of ions and the polarization of bipolar molecules in living cells. The magnetic field also stimulates cell metabolism and mitosis in cells. Meristematic plants become plants. Variable magnetic fields, if used properly, have a great stimulatory effect on cell proliferation and the growth of plants and fungi. According to studies, the use of electromagnetic field may also affect the seed germination of medicinal plants and improve seed germination, but taking into account that the intensity and duration of these pretreatments It can have different effects in different seeds, it is better to do studies with different intensities and durations of these treatments before recommending these methods for commune failure. Due to the great medicinal properties of Echinacea and the lack of information about the effect of these treatments on germination of this species, the aim of this study was to investigate the germination of Echinacea seeds after electromagnetic field treatments.Therefore, the aim of the present study was to investigate the germination of Echinacea seeds after electromagnetic field treatments.
In order to investigate the intensity of 100 ms and the duration of the magnetic field on the germination components of Echinacea seeds in the laboratory of production and processing of medicinal plants, Faculty of Agriculture, University of Tabriz in a completely randomized design with three replications in 2015 Done. Experimental treatments included a constant magnetic field strength (100 ms) and the duration of exposing the seeds to a constant magnetic field for 5, 10, 15, 20, 25, 30, 35, 40, 45, 50 and 55 minutes and control treatment (without magnetic field exposure). The dried seeds were placed in batches of 75 in a thin transparent plastic tube between the poles of the magnet with a constant magnetic field strength and time required, and then placed in batches of 25 in each petri dish. To apply the magnetic field, a magnetic field inductor was used, which consisted of a pair of magnets with the ability to adjust the distance from each other. The two magnets were embedded in the machine so that they were attracted to each other. The distance between the two magnets was adjusted by measuring the intensity of the magnetic field with a teslamter device so that the magnitude of the magnetic field was 100 milliseconds. First, the seeds were disinfected by soaking in 10% sodium hypochlorite for three minutes and then washed several times using distilled water to remove residual sodium hypochlorite from the seed surface. In this experiment, after applying the treatments, 25 seeds of each treatment were placed in three replications in a nine-centimeter dish with a Whatman filter paper. The petri dishes were then placed in a germinator at 22 ° C for 12 hours for germination for 15 days. The number of germinated seeds (2 mm rootlet exit was considered as germination criterion) was counted and recorded daily. On the last day, to obtain the length of the root and stem, first the root was separated from the stem and their length was measured with a ruler, as well as the fresh weight of the root and stem. Which was calculated by the scales with an accuracy of 0.001 and then to obtain the dry weight of the samples, after weighing, they were placed in an oven at 70 ° C for 24 hours and finally the weight Their dryness was calculated by a scale with an accuracy of 0.001. Also, ratio of root length to stem length, ratio of root dry weight to fresh weight of root and ratio of dry weight of stem to fresh weight of stem Was calculated. The following equations were used to determine the germination rate (GS) and germination percentage (G%).
The results of analysis of variance showed: root dry weight, shoot dry weight, germination rate, ratio of root dry weight to fresh root weight and ratio of stem dry weight to fresh weight of stem At the level of 1% probability and fresh weight of stem, root length, germination percentage and ratio of root length to stem length were significant at 5% probability level and fresh weight of root And shoot length was not significant. Comparison of means showed that the highest fresh weight of shoots in 15 minutes treatment (exposure to magnetic field), highest dry weight of shoots and shoots, root-shoot length, germination percentage And germination rate and ratio of root length to stem length in 15 minutes treatment (exposure to magnetic field) and maximum root dry weight to root fresh weight and stem dry weight to Stem fresh weight in 20 minutes treatment (magnetic field exposure) and the lowest amount of root and stem fresh weight, root dry weight, root length, ratio of root length to Stem length and shoot to dry weight ratio of shoot to fresh weight in 50 minutes (exposure to magnetic field), minimum shoot dry weight and shoot length in 30 minutes (exposure Magnetic field exposure), the lowest percentage and germination rate in 20 minutes treatment (magnetic field exposure) and the lowest ratio of root dry weight to fresh root germ weight in control (without exposure Magnetic field) was observed. Based on the results obtained from the comparison of means, 10 minutes of treatment (magnetic field exposure) had the greatest effect on the measurement components compared to the control.The magnetic field not only allows water to penetrate the seed faster, but also affects the rate of enzymatic reactions. Increased water absorption in the first stage caused the inflammation of the seeds to be affected by the magnetic field, which resulted in an increase in their fresh weight. The magnetic field reduces the surface tension and viscosity of water, as well as the latent heat of vaporization, which eventually leads to rapid evaporation of water. These three phenomena are related to the power of action designated as hydrogen bonding. Changes in these indices lead to faster penetration of water into the seeds, causing faster and more effective germination of seeds.