P Abdolmaleki, B Nahidian, A Paeez, F Ghanati,
Volume 12, Issue 3 (11-2012)
Abstract
There are many reports on the effects of magnetic fields on the plants, but the exact mechanisms of these effects are poorly understood. In this study we compared the effects of different magnetic fields on the germination and early growth of wheat seeds. The seeds of wheat (Triticum aestivum L.) in two groups, dry and imbibed, were treated with static magnetic field (SMF 30mT) and electromagnetic field (EMF 10KHz) for 4 days and 5 hour for a day. After treatment, seed water uptake, the percent and speed of germination, early growth characteristics and electrolyte leakage of seeds coat and seedlings root membrane were estimated. The results showed that treatment with SMF and EMF had not significant effect on the germination percent of imbibed wheat seeds, but accelerated the speed of germination, fresh and dry weight and vigor index II, compared to control groups. In dry wheat group only positive effect of magnetic field had seen on the length of seedlings. Magnetic field treatment decreased the electrolyte leakage of seeds coat and seedlings root membranes however had not increased the water uptake of seeds. So elevated speed of germination and growth of seedlings probably was due to increase of membrane integrity, content or activity of the germination enzymes or antioxidant enzymes. In general, effects of magnetic field on the imbibed seeds is better than dry seeds and SMF had better effect than EMF on the germination and early growth of wheat seedlings.
Latifeh Pourakbar, Latifeh Pourakbar,
Volume 15, Issue 2 (2-2015)
Abstract
Effects of decreased ozone and increased UV radiation have been studied by many researchers. The aim of this study was to investigate the effects of UV-B radiation on Melissa officinalis L. and to study the impact of salicylic acid and magnetic fields in reducing the harmful effects of radiation on plants. The Melissa officinalis L. plants were treated with 28_+2 Celsius temperature for about 60 days. The light intensity was 150 µ E mˉ² Sˉ¹ and the lightness-darkness condition was8-16 hours. UV treatment was applied after the six-leaf stage and UV-B radiation was applied for a period of 15 days, the time for each application was 20 minutes. Salicylic acid was sprayed on the plants after the six-leaf stage with a concentration of 1 mmol. Magnetic field treatment was applied for an hour with intensities of 0, 40 and 85 mT. The results indicated that the UV-B radiation led to reduction in dry and fresh weight, root elongation and shoots. The radiations also reduced the photosynthetic pigments (chlorophyll a, chlorophyll b and carotenoid) and sugar rate and soluble proteins amount. The phenylalanine ammonia-lyase compounds rate and UV-absorbing compounds were increased under the effect of UV-B radiation. The results showed that treatment with salicylic acid and magnetic fields caused a reduced damage to the plant which had been created due to UV-B radiation and were able compensate for changed factors that had been changed because of UV radiation.
