بررسی تأثیر میدان مغناطیسی بر مؤلفه‌های جوانه‌زنی گیاه دارویی سرخارگل ‏‎(Echinaceae purpurea L.‎)‎

Introduction
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. ‎

Methodology
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%).‎
Conclusion
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.‎