The effect of a magnetic field on the phenolic composition and virus sanitation of raspberry plants

A magnetic pulse treatment led to an increase in the Raspberry bushy dwarf Idaeovirus-free microplants’ output and their phenolic composition change. The greatest output of the virus-free raspberries microplants (80–82%) was marked after complex treatment with pulsed and rotating magnetic fields with a time-changing frequency from 3.2 to 51 Hz, as well as with a pulsed magnetic field with a frequency from 1 to 10 Hz. The pulsed and rotating magnetic fields’ complex effect resulted in the gallic and salicylic acid content increase by 14 % and 71%, respectively, compared to the untreated variant. The chlorogenic, salicylic and gallic acids’ active synthesis was observed 72 hours after the magnetic treatment with a frequency from 3.2 to 51 Hz. There was a tendency for the amount of the phenolcarbonic acid to decrease 14 days after the magnetic treatment, except for the variant with the pulsed and rotating field treatment.

The Effects of Magnetic Treatment On Seedling Growth, Nitrogen Metabolism, And Mineral Nutrient Contents In Populus×Euramericana 'Neva' Under Cadmium Stress

Background: The potted experiment was carried out to investigate the mechanism of nutrient metabolism and seedling growth caused by magnetic treatment (MT) following exposure to cadmium (Cd) stress. One-year-old seedlings of Populus×euramericana 'Neva' were treated with different Cd(NO3)2 solutions for 30 days. Properties of seedling growth and root morphology were promoted by MT under Cd exposure.Results: Contents of ammonium (NH4+-N), nitrate (NO3--N), and total nitrogen (TN) in leaves, also NH4+-N and TN in roots, were increased by MT combined with Cd-stress, although NO3--N content was decreased. Activities of nitrate reductase (NR), nitrite reductase (NiR), glutathione reductase (GR), and glutamate synthase (GOGAT) in leaves and activities of NR, GS and GOGAT in roots were stimulated by MT; conversely, NiR activity in roots was inhibited. MT improved the synthesis of cysteine (Cys) and glutamine (Gln) in leaves and reduced the contents of glutamic acid (Glu) and glycine (Gly), while contents of Cys, Glu, Gln, and Gly were increased in roots. (4) The contents of Ca, Mg, Fe, Mn, Zn and Cu were increased by MT under Cd stress in leaves, whereas content of K was reduced. In roots, contents of K, Ca, and Fe were increased by MT under Cd-stress, but the contents of Na, Mg, Mn, Zn, and Cu were decreased.Conclusions: Magnetization could regulate the uptake of mineral nutrients by roots and translocation from the roots to aboveground parts by affecting the root morphology. MT could also improve nitrogen assimilation and the synthesis of free amino acids by stimulating the activities of key enzymes.

Effect of Magnetic Treatment of Water or Seeds on Germination and Productivity of Tomato Plants under Salinity Stress

Salinity is an abiotic stress that reduces the seed germination and productivity of tomatoes. Magnetic treatment has been shown to have a positive effect on the seed germination, seedling growth, and productivity of various crop species. Therefore, three experiments were conducted to evaluate whether treating saline water or seeds with a magnetic field can improve the seed germination and productivity of tomatoes (Solanum lycopersicum) under salinity stress. To evaluate seed germination and seedling growth in response to a magnetic field, two laboratory experiments were carried out by passing four saline water solutions of NaCl (0, 5, 10, and 15 dS/m) through a magnetic field (3.5–136 mT) or exposing tomato seeds to the same magnetic field for 20 min before sowing. In a greenhouse experiment, plants were irrigated with different magnetically-treated and untreated saline water solutions to evaluate plant growth. Magnetic treatment of water or seeds improved seed germination percentage, speed of germination (lower mean time to germination), and seedling length and dry weight in the two laboratory experiments, especially under salinity stress of 5 and 10 dS/m. As the salinity level increased, germination performance and plant growth were significantly decreased. Irrigating tomato plants with magnetically-treated water improved plant height, stem diameter, and fruit yield per plant compared to untreated water, especially under salinity of 0 and 5 dS/m. In conclusion, magnetic treatment of saline water or seeds improved germination performance, plant growth, and fruit yield of tomatoes under saline conditions.

YIELD AND QUALITY OF BELL PEPPER FRUITS IRRIGATED WITH MAGNETICALLY TREATED WATER

The application of magnetically treated water is a valuable technique for crop irrigation to enhance the yield and quality of agricultural products. This study aims to evaluate the effect of irrigation water depths and the application of water with and without magnetic treatment on the yield and quality of bell pepper fruits in a controlled environment, verifying the effect of magnetically treated water on soil water retention. Two experiments were conducted in the Irrigation Technical Center of the Universidade Estadual de Maringá, Maringá/PR; the first on Summer 2017-2018, and the second on Winter-Spring 2018. A randomized block design with a factorial scheme 3 x 2 with four repetitions was used for the first experiment and a 2 x 2 scheme with six repetitions for the second. The first factor was the water replacement levels (based on the crop evapotranspiration), and the second the irrigation water treatment, with or without magnetic treatment. The yield and number of fruits were determined after six and four harvests in the first and second experiments. Quality characteristics (soluble solids level, pH, and titratable acidity) were evaluated from three fruits of each plant. The data was submitted to the Tukey test (p ≤ 0.05). It was verified that the application of magnetically treated water did not influence yield. However, it increased the levels of soluble solids and pH. To evaluate the effect of applying magnetically treated water on soil retention, 12 pots filled with soil and without plants were used. An increase in the gravimetric soil moisture using magnetically treated water was perceived, demonstrating higher water retention when using the irrigation method.

Magnetic Field Stimulation Effect on Germination and Antioxidant Activities of Presown Hybrid Seeds of Sunflower and Its Seedlings

Magnetic field biostimulation plays a significant role in enhancing the germination of seeds and increasing the metabolic rate. The low magnetic field effect for long exposure time and its effect on antioxidant profiling have not been studied. Therefore, in the recent findings, the static magnetic field’s impact on sunflower seeds subjected to the magnetic field at varying intensity (millitesla) for different exposure times was examined. The effectiveness of magnetic biostimulation on presown sunflower seeds, growth parameters of seedlings (biomass, root and shoot length, fresh and dry weight of roots, shoots, leaf, and height of plants), and antioxidant activities were also studied. It has been revealed that magnetic treatment at 50 mT/45 min greatly influenced the growth parameters, including mean germination growth (100 ± 0.02) and final emergence rate. Concerning the antioxidant parameters, seed variety FH620 at 500 µg/µL concentration showed significant results compared to other varieties. FTIR was employed to determine the conformational changes and functional groups of organic compounds from sunflower seedlings. Tocopherol analysis by HPLC showed that magnetic treatment at 50 mT/45 min had a higher concentration of vitamin E compared to the control group. These modifications indicated that magnetic field induction enhanced seeds’ inner energy that led to seedlings’ growth and development enhancement. Besides, magnetic field pretreatment has been shown to have a beneficial influence on sunflower seeds and their bioactive compounds. Future studies should be focused on growth characteristics at the field level and yield attributes.