Bioelectromagnetics Effect of Stationary Magnetic Field Strengths of 150 and 200 mTon Reactive Oxygen Species Production in Soybean M.B. Shine, 1 * K.N Guruprasad, 1 and Anjali Anand 2 1 School of Life Sciences, Devi Ahilya University, Indore, Madhya Pradesh, India 2 Division of Plant Physiology, Indian Agricultural Research Institute, New Delhi, India Our previous investigation reported the beneficial effect of pre-sowing magnetic treatment for improving germination parameters and biomass accumulation in soybean. In this study, soybean seeds treated with static magnetic fields of 150 and 200 mT for 1 h were evaluated for reactive oxygen species (ROS) and activity of antioxidant enzymes. Superoxide and hydroxyl radicals were measured in embryos and hypocotyls of germinating seeds by electron paramagnetic reso- nance spectroscopy and kinetics of superoxide production; hydrogen peroxide and antioxidant activities were estimated spectrophotometrically. Magnetic field treatment resulted in enhanced production of ROS mediated by cell wall peroxidase while ascorbic acid content, superoxide dismutase and ascorbate peroxidase activity decreased in the hypocotyl of germinating seeds. An increase in the cytosolic peroxidase activity indicated that this antioxidant enzyme had a vital role in scavenging the increased H 2 O 2 produced in seedlings from the magnetically treated seeds. Hence, these studies contribute to our first report on the biochemical basis of enhanced germina- tion and seedling growth in magnetically treated seeds of soybean in relation to increased produc- tion of ROS. Bioelectromagnetics ß 2012 Wiley Periodicals, Inc. Key words: antioxidant enzymes; magnetic field; reactive oxygen species INTRODUCTION Stimulation of seeds with magnetic fields as a way to increase their quality of germination has caught the interest of many scientists. Magnetic treat- ment acts as a non-invasive external stimulant for the germination and improved vigor of many seeds [Pittman, 1965; Aladjadjiyan and Ylieva, 2003; Florez et al., 2007]. Several scientific reports also show that magnetic field exposure increases the ger- mination of low viability seeds and improves their quality and sprouting rate [Alexander and Doijode, 1995; Carbonell et al., 2008]. These results can be exploited in improving vigor and field emergence in seeds [Alexander and Doijode, 1995; Carbonell et al., 2008]. Pre-sowing magnetic field treatment for enhancing seed performance, if standardized, could lead to commercial application. However, not much information is available on the biochemical and bio- physical mechanism occurring in magnetically treated seeds during germination [Galland and Pazur, 2005]. It is believed that the magnetic field influences the structure of cell membranes and increases their permeability and ion transport through the ion chan- nels, which then affects some metabolic activity [Reina and Pascual, 2001]. A higher content of hy- drolyzing enzymes after pre-sowing treatment with magnetic fields has been reported in Helianthus annuus [Vashisth and Nagarajan, 2010]. Increased levels of free radicals in seeds after treatment with laser light and magnetic fields, accompanied by en- hanced dynamics of seed germination, was also reported in faba bean seeds and pea seeds [Podlesny et al., 2001, 2005]. In seeds, reactive oxygen species (ROS) pro- duction has been considered for a long time as being very detrimental, since the works dealing with ROS were mainly focused on seed ageing or seed desicca- tion—two stressful situations that often lead to Additional Supporting Information may be found in the online version of this article. Grant sponsor: Indian Council of Agricultural Research, New Delhi, India; Grant number: NFBSRA/PCN/AP-09/2006-07. *Correspondence to: M.B. Shine, School of Life Sciences, Devi Ahilya University, Khandwa Road, Indore 452001, Madhya Pra- desh, India. E-mail: shinemb12@gmail.com Received for review 7 March 2011; Accepted 4 December 2011 DOI 10.1002/bem.21702 Published online in Wiley Online Library (wileyonlinelibrary.com). ß 2012 Wiley Periodicals,Inc.