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Shocking Discoveries: The Applications and Putative Mechanisms of the Effects of Electric and Magnetic Fields on Plants Ian Maynor “Life and death appeared to me ideal bounds, which I should irst break through, and pour a torrent of light into our dark world.” - Dr. Victor Frankenstein, Frankenstein by Mary Shelley
Introduction Images of Frankenstein’s creation of life through the powerful force of electricity can be found everywhere throughout popular culture. his ubiquitous motif relects a human fascination with the seemingly supernatural properties of electromagnetism, a power considered so great that we have often imagined it can achieve the impossible; even bring the dead back to life. he study of electromagnetic energy in living things, bioelectromagnetism, began in the late 1700s when the Italian scientist Luigi Galvani discovered that applying static electricity to frog legs caused them to move. Since then, iction has used the imagined power of electromagnetism to create villains such as Frankenstein’s monster and in the powers of superheroes such as Magneto or Storm. Yet perhaps just as shocking are the real-life applications of bioelectromagnetism, speciically in its potential use in plants and agriculture to improve plant growth, yield, germination rate, and nutrition. Even simply exposing plant seeds and irrigation water to diferent types of electromagnetic energy have proven to achieve similar efects in a wide variety of plants and even livestock [1]. hese results suggest that the exposure of plants to magnetic and electrostatic ields could provide an ecologically friendly, afordable way to increase crop production without polluting the soil with chemical fertilizers [2]. here seem to be few, if any, drawbacks to these novel approaches; a review paper on the potential genotoxicity of electric and magnetic ields dismissed claims in 34 studies that extremely low frequency electric and magnetic ields could harm plant genomes [3]. here are still, however, many issues to resolve before we can approach a comprehensive understanding of various types of electromagnetic energy on crops and eventually apply this knowledge on a large scale: i.e., which methods of applying electromagnetic energy best improve plant growth and yield, whether these methods can increase nutrition and productivity as well as growth, and most importantly, what the causes behind these astonishing indings are.
Varying Methods of Applying Electric and Magnetic Fields to Plants In 1930, the Russian researcher Savostin conducted one of the irst studies on the efects of magnetic ields on seeds when he observed increased oxidation rates in wheat seedlings under magnetic conditions [4]. Over a decade later, researchers observed changes in seed germination due to magnetic ields [5]. Since then, researchers have tested a wide variety of methods of exposing plants to electric or magnetic ields to improve their germination and growth. Between electric and magnetic ields, there is a wide array of diferent techniques of applying electromagnetic energy to plants in hopes of improving their growth and yield. Electric ields are forces formed by a diference between static charges, while magnetic ields are forces created by moving charges. Although these forces are diferent, researchers have observed strikingly similar results in plants whether using electric or magnetic ields. Some researchers have achieved improvements in plant growth and yield by exposing plants to magnetic ields while they grow. Naturally, all plants grow in the presence of magnetic ields, as the earth’s magnetism creates a global magnetic ield. However, by applying magnetic ields beyond the local geomagnetic ield, researchers have achieved impressive results in improving growth and yield. Novitsky et al. grew green and bulb onions under horizontal permanent magnetic ields of strengths around 43 A/m produced by Helmholtz coils (Figure 1) and observed increased bulb sprouting in both green and bulb onion [6]. he same study also found that the magnetic ields accelerated sprouting in both types of onions, which the study attributed to cell elongation; however, this stimulating efect of permanent magnetic ields only lasted in the sprouting stage of the onion’s growth [6]. he magnetic ields were also found to increase plant yield by increasing the number of sprouts in green onions and the number of sprout bunches in bulb onions; this focused growth suggested that permanent magnetic ields enhance the genetically determined growth patterns seen in untreated onions [6]. Permanent alternating magnetic ields, created by continuous, alternating electric currents, have also Volume 2 | 2012-2013 | 51
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Methods of Exposing Plants to Magnetic Fields
Figure 1. Helmholtz coils
Figure 3. Helmholtz coils Figure 5.
Figure 2. Figure 4. been shown to improve plant growth and yield. EĹ&#x;itken and Turan grew strawberry plants beneath electric wires through which an alternating current was passed, creating an alternating magnetic ield which magnetically treated the plants beneath the wires (Figure 3) [7]. hey found that weaker magnetic ields (0.096 T) increased fruit yield, fruit number per plant, and average fruit weight in strawberries compared to the control and treatments with stronger ields [7], showing that continuous exposure to alternating magnetic ields can increase plant yield just as continuous exposure to nonalternating ields has [6]. Similar results have been achieved in a number of studies on the efects of pre-sowing magnetic treatments of plant seeds in a variety of plants. In such studies, seeds are exposed to magnetic or electric ields before sowing, and the efects on growth and yield are observed. Some of these studies used Helmholtz coils (Figure 4) to expose seeds to magnetic ields ranging in strength from 0 to 10 mT [2, 8, 9]; others used diferent methods to magnetically treat seeds, such as placing the seeds between two bar electromagnets [10]. Researchers have observed that pre-sowing treatment with pulsed magnetic ields improved plant growth and yield [8], while pre-sowing magnetic treatments on tomato seeds have been found to signiicantly improve percent germination rates, plant growth, yield, and fruit size [11]. In contrast, electric ields with greater intensities and certain exposure times were found to inhibit germination in tomato seeds [10, 11]. Even more interesting, however, magnetic treatments ranging from 100 to 170 mT and 3 to 10 minutes were found to signiicantly delay the onset of geminivirus and early blight in tomatoes and were observed to cause a reduced infection rate of early blight [10]. Similar efects, such as increased germination and yield, have been repeated in the nonfood crop cotton as well [2]. However, as seen throughout all of these studies, the efects of magnetic ields on plants difer from one species to the next and even between varieties of the same species [2].
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Stationary magnetic ields have also been demonstrated to increase the germination rate and growth of plants. he stationary magnetic ields used in such experiments are produced by the permanent magnets found in everyday life. Researchers have found that exposing corn seeds to stationary magnetic ields at various strengths increased their height and weight as seedlings, with signiicant improvements observed when the seeds were exposed for 24 hours or more at magnetic ield strengths of 125 mT and 250 mT [12]. As a reference, kitchen magnets have a strength of around 5 mT, sunspots a strength of about 150 mT, and loudspeaker magnets a strength of around 1 T. Similar studies have shown that while magnetic ields improve plant germination rate, the ields do not afect the total amount of germination under laboratory conditions (as opposed to ield conditions), as the increased germination rate only allowed the plants to reach the same saturated amount of germination at a faster pace than the control [11, 12]. However, magnetic ield exposure has been shown to increase the total number of germinated seeds under ield conditions [2]. Yet another approach to increasing germination in plants involves subjecting seeds to high voltage electric ields (HVEF) by placing them between metal plates charged with high voltages, producing electric intensities equal to 450 kV per meter of space between the two plates. HVEF have been found to increase the germination rate and total germination of aged wet rice seeds and signiicantly increase their vigor [13, 14].
Figure 6. Even more intriguing studies have observed that magnetic treatment of irrigation water can improve crop and livestock yield [1, 15]. Studies such as these run water through magnetic treatment devices, in which water is run through a pipe positioned between two magnets [15]. Fas-
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REviEw cinatingly, similar efects are found in livestock as well. Lin and Yotvat tested the efects of magnetically treated irrigation and drinking water on cows, geese, sheep, turkeys, and melons. Treated cows were found to produce more milk, be more fertile, and grow faster than the control group, while treated geese and turkeys were heavier than the controls [1]. Treated sheep’s milk, meat, and wool yield were all increased [1]. Lin and Yotvat concluded that these data purport the beneits of using magnetically treated water on an agricultural scale, including applications in ish farming, algae, produce, and livestock, using electromagnetic units for treating water which are already commercially available [1].
nisms which could then be applied to a larger number of crops and methods to pave a path for the potential largescale agricultural use of bioelectromagnetics in the future.
Efects on Nutrition and Productivity Some of the studies on the abilities of magnetic ields to improve crop yield have also found that magnetic ields increase certain nutritional values of plants. Novitsky et al. observed that magnetically treated onions contained larger amounts of chlorophyll and protein, but not carbohydrates, in comparison to the control [6]. Lin and Yotvat found the magnetic treatment of water increased the sugar content of melons and made the meat of treated cows leaner compared to controls [1]. However, few studies have studied the efects of magnetic ields on plant nutrition besides studies focusing on nutrient uptake as a potential explanation for increased germination and growth in magnetically treated plants. Additional research is needed to explore the ability of magnetic ields to increase the nutritional values of various plants, which holds the promise of producing not only higher quantity but also higher quality plants.
he Mechanisms behind the Data Figure 7. he magnetic treatment of water has also been suggested to cause treated plants to use water more eiciently. Maheshwari and Grewal found that celery irrigated with magnetically treated water experienced signiicant increases in productivity (weight produced per volume of water used) [15]. Although the total amount of water used for the treated plants was the same as the control, the increased yield induced by the magnetic ields accounted for the increase in water productivity [15]. However, few, if any, other studies have investigated the efects of magnetic ields on water productivity; further studies must be done in this area to either support or counter claims that magnetic ields may generally increase water productivity. If proven, increased water productivity in plants under magnetic treatments could add to the already sizable number of beneits magnetic ields lend to plants and would be especially useful for farmers growing crops in dry regions. As can be seen, a large number of studies have used electromagnetic energy to increase germination, growth, and yield in plants through a variety of methods: continuous exposure to magnetic ields, seed exposure to magnetic ields, seed exposure to high voltage electrostatic ields, and irrigation and drinking water exposure to magnetic ields. However, no studies have compared any of these methods side by side to see which is most efective in improving plant germination, growth, and yield. Little research has been done on how diferent plants are afected using the same method of exposing plants to a certain type of electric or magnetic ield. While researchers have found many speciic beneits of electric and magnetic ields on plants, broader studies should be conducted to ind basic mecha-
While many studies have tested the abilities of magnetic ields to improve plant growth and yield, few have investigated the causes of these strange phenomena. Many papers have noted increases in nutrient uptake in plants treated with magnetic ields [7, 8, 11]. Eşitken and Turan attributed magnetically treated plants’ selective uptake of positive ions over negative ions to the negative electric charge of plant cells [7, 16], which cause them to uptake positively charged ions. hese results suggest that magnetic ields may increase the negative charge of plant cells, thereby increasing their uptake of positive ions, many of which are nutritional to plants and may help improve a plant’s growth and yield. Moon and Chung observed that external electric and magnetic ields inluence ion activation and dipole polarization in living cells, providing a possible explanation for the increase in the plants’ nutrient uptake due to magnetic ield exposure [11]. Another study proposed that the magnetic treatment of plants electromagnetically induced change in the electrostatic balance of plant systems at the cell membrane level, which is the main site of any inhibition or enhancement of plant growth [2]. It has also been proposed that magnetic ields could afect the transport of charged solutes into the cell by the activity of enzymes controlling the local extensions of plant cell [2]. he correlation between mineral uptake and magnetic ields’ positive efects on plants suggests that former may also be one of the factors responsible for the unique efects of magnetic ields on plants. It has been proposed that magnetically treated plants release organic compounds into the rhizosphere, the soil surrounding the plant, which may increase P and K desorption, the release of phosphorus and potassium through or from a surface; these elements would therefore become more available to Volume 2 | 2012-2013 | 53
Street Broad Scientific the plant, aiding plant growth [15]. Results from the same study have suggested that magnetically treated water also improved availability, uptake, assimilation, and mobilization of these nutrients within the plant system, providing a possible explanation for the treated plants’ increased water productivity when compared to the control [15]. Other evidence suggest that the positive efects of magnetic treatments on plants may result from a reduced rather than increased accumulation of certain minerals; Maheshwari and Grewal proposed that the magnetic treatment of water may inhibit the plants uptake of Na, thereby decreasing Na toxicity [15], which other studies have found to limit plant growth [17, 18,19]. Another possible explanation for ability of magnetic ields to enhance plant germination, growth, and yield is via the water relations within plants. One study found results suggesting that stationary magnetic ields change the mechanism of water uptake in lettuce seeds, allowing them to absorb more water [9]. Citing a paper in which increased osmotic pressure and therefore increased water uptake were suggested to stimulate cell growth rates [20], the researchers concluded that the correlation between water uptake and magnetic ields they found may be responsible for the increased, magnetically induced germination rates found in other studies [9]. Another study proposed that non-uniform magnetic ields may energetically excite one or more parameters of the cellular substratum, such as proteins and carbohydrates, or water within seeds; after these magnetically exposed seeds acquired water, the activation and production of enzymes and hormones would be enhanced due to initial stimulation from magnetic ields, which could lead to improved plant germination, growth, and yield [10]. Other studies found that magnetic treatments increase protein synthesis and content in plant cells [6, 8]. However, since little research has been done on the relationships between magnetic ields and water uptake, cellular substratum stimulation, and photosynthesis, these three plausible explanations for the efects of magnetic ields on plants must be more thoroughly researched to reach informed conclusions on the true causes of magnetic ields’ special efects on plants. Several studies have also pointed to enzymes as possible factors in magnetic ields’ efects on plants by linking electric and magnetic ield exposure to enzyme activity [8, 21]. Radhakrishnan and Kumari proposed that magnetic ields afect the photosynthetic enzyme Rubisco subunits, which are largely responsible for carbon ixation in plants and therefore lead to enhanced carbon ixation and growth [8]. Pulsed magnetic ields were also found to increase activity of catalase (an enzyme which catalyzes the decomposition of hydrogen peroxide to water and oxygen) in soybean seedlings, suggesting that magnetic ield treatment leads to increased catalase activity and therefore greater decomposition of harmful reactive oxygen species; moreover, the formation of water may have in turn enhanced plant growth [8]. Nazar et al. concluded that further research should be conducted regarding whether the bio54 | 2012-2013 | Volume 2
REviEw logical efects of electric and magnetic ields is ield or cell speciic [21]. Another study claims that increased growth and yield in plants exposed to electric or magnetic ields could be due to an increased activity of enzymes that decompose harmful reactive oxygen species [14]. Wang et al. additionally proposed that magnetic treatments increase lipid peroxidation of harmful reactive oxygen species and that increased enzyme activity due to electrostatic ield treatment leads to greater lipid peroxidation, less damage to seedlings, and therefore more growth in seedlings [14]. Furthermore, enzyme activity may be determined by a factor previously discussed, ion accumulation: one study found that metal ions can inhibit acid phosphatase to varying degrees in corn and soybean roots, suggesting a link between ion concentration and enzyme activity [22]. his could mean that the increased ion concentrations caused by electric or magnetic ield exposure may be responsible for increased or decreased enzyme activity. Lin and Yotvat found that the efects of treating irrigation and drinking water depended on the type of water, water content, temperature, equipment, equipment location, and operational factors such as water volume, speed of low, installation, maintenance, etc., [1] but provided no explanation for the increases in growth, yield, and nutrient content in magnetically treated crops and livestock observed in their study. A possible explanation for these results is that magnetic ields alter some element of water which makes them more functional within the plant system and probably afects plant growth at the cellular level [15]. Recent studies have found that magnetic ields do, in fact, change some chemical and physical characteristics of water [23, 24], and these efects have been observed to last long after the magnetic ield is removed [25]. Researchers have discovered that magnetic ields increase the size of water molecule clusters bound by hydrogen bonds in liquid water [24]. his relates to indings that magnetic ields increase the strength of hydrogen bonds in water [26]; this correlates to a weakening of van der Waals forces in water, since the delicate balance between conlicting hydrogen bonding and non-hydrogen-bonding forces in water clusters means that stronger hydrogen bonding will accompany weaker van der Waals forces [26]. Researchers have proposed that magnetic ields create dampening forces which reduce the thermal motion of charges inherent in water, strengthening the hydrogen bonding between water molecules [27]. hey also found that magnetic ields increase the rate of evaporation by decreasing the strength of van der Waals forces and increase water’s boiling point, supposedly due to increased hydrogen bonding [27]. By increasing the strength of certain bonds within water, magnetic ields could possibly afect the transpiration and uptake of magnetically treated water in plants, ofering a possible explanation for the ability of magnetically treated water to increase water productivity. Strong magnetic ields have been found to enhance salt mobility as well [28], which could account for the greater ion concentra-
REviEw tions found by Maheshwari and Grewal that may be responsible for the efects of magnetic ields on plants [15]. Magnetic ields also have the ability to increase proton spin relaxation, which may quicken some proton-transfer dependent reactions [29], which may help explain the increased enzyme activity proposed by Wang et al. to help promote seedling growth [14]. Many studies concede that researchers still do not know enough about the mechanisms causing magnetic and electric ields to increase germination, growth, and yield in plants. Comprehensive studies must test a variety of possible factors to explain this behavior at a cellular level so that broader generalizations on the mechanisms of these phenomena can be reached. Once they are determined, we will be able to better understand if, when, and how electric and magnetic ields can improve plant germination, growth, and yield and determine ways to maximize these beneits.
Conclusion Much like the observers of Galvini’s experiments, we are currently testing the efects of electromagnetic energy on a wide variety of organisms, seeing if this powerful force can increase the germination, growth, and ultimately yield of both plants and animals. Yet, similar to the men and women of Galvini’s day, we are still unsure of the exact science behind the radical results we see. If we truly want to unlock the potential of electric and magnetic waves in maximizing plant and livestock production, to break the “ideal bounds” Dr. Frankenstein referred to, we must irst deinitively determine the causes of these strange phenomena. In conclusion, there remains much to be probed and discovered in the study of electric and magnetic ields’ effects on plants and livestock. First, we must determine the general causes of the peculiar behavior of plants exposed to magnetic or electric ields, such as their tendency toward increased germination, growth, yield, productivity, and nutrition. After establishing a irm and broad conceptual basis, which we now lack, we can then conirm or disprove claims that magnetic ields can increase productivity and nutrition and additionally determine how to manipulate the factors behind this amazing behavior to maximize the beneits of electric and magnetic ields on plants. From there, we can then commercialize this process for wide-scale agricultural applications which could meet the constantly growing demand for food in an ever expanding world.
References [1] Lin, I.J., and J. Yotvat. 2002. Exposure of irrigation and drinking water to a magnetic ield with controlled power and direction. Journal of Magnetism and Magnetic Materials 83: 525-526.
Street Broad Scientific [2] Leelapriya, T., K.S. Dhilip, and P.V. Sanker Narayan. 2003. Efect of weak sinusoidal magnetic ield on germination and yield of cotton (Gossypium spp.). Electromagnetic Biology and Medicine 22: 117-125. [3] McCann, J., F. Dietrich, and C. Raferty. 1998. he genotoxic potential of electric and magnetic ields: an update. Mutation Research/ Reviews in Mutation Research 411: 45-86. [4] Savostin, P.W. 1930. Magnetic growth relations in plants. Planta 12, 327. [5] Murphy, J.D. 1942. he inluence of magnetic ield on seed germination. Am. J. Bot. 29(Suppl.), 15. [6] Novitsky, Y.I., G.V. Novitskaya, T.K. Kocheshkova, G.A. Nechiporenko, and M.V. Dobrovol’skii. 2000. Growth of green onions in a weak permanent magnetic ield. Russian Journal of Plant Physiology 48: 709-715. [7] Eşitken, A., and M. Turan. 2004. Alternating magnetic ield efects on yield and plant nutrient element composition of strawberry (Fragari ananassa cv. Camarosa). ActaAgric. Scand., Sect. B, Soil and Plant Sci. 54: 134-139, 2004. [8] Radhakrishnan, R. and B.D.R. Kumari. 2012. Pulsed magnetic ield: A contemporary approach ofers to enhance plant growth and yield of soybean. Plant Physiology and Biochemistry 51: 139-144. [9] Reina, F.G., L.A. Pascual, and I.A. Fundora. 2001. Inluence of a stationary magnetic ield on water relations in lettuce seeds. Part II experimental results. Biolectromagnetics 22: 596-602. [10] De Souza, A., D. Garcia, L. Sueiro, F. Gilart, E. Porras, and L. Licea. 2006. Pre-sowing magnetic treatments of tomato seeds increase the growth and yield of plants. Bioelectromagnetics 27: 247-257. [11] Moon, J.D., and H.W. Chung. 2000. Acceleration of germination of tomato seed by applying AC electric and magnetic ields. Journal of Electrostatics 48: 103-114. [12] Flórez, M., M.V. Carbonell, and E. Martínez. 2007. Exposure of maize seeds to stationary magnetic ields: effects on germination and early growth. Environmental and Experimental Botany 49: 68-75. [13] Wang G., J. Huang, W. Gao, J. Li, R. Liao, and C.A. Jaleel. 2009a. Inluence of high voltage electrostatic ield (HVEF) on vigour of aged rice (Oryza sativa L.) seeds. Journal of Phytology 2009, 1: 397-403. [14] Wang G., J. Huang, W. Gao, J. Lu, J. Li, R. Liao, C.A. Jaleel. 2009b. he efect of high-voltage electrostatic ield (HVEF) on aged rice (Oryza sativa L.) sees vigor and lipid peroxidation of seedlings. Journal of Electrostatics 67: 749-764. [15] Maheshwari, B.L., and H.S. Grewal. 2009. Magnetic treatment of irrigation water: its efects on vegetable crop yield and water productivity. Agricultural Water Management 96: 1229-1236. [16] Marschner, H. 1995. Mineral nutrition of higher plants. Academic Press Limited. 24-28 Oval Road, LonVolume 2 | 2012-2013 | 55
Street Broad Scientific don NW1 7DX, 889 pp. [17] Franรงois. L.E., T.J. Donovan, E.V. Maas, and S.M. Lesch. 1994. Time of salt stress afects growth and yield components of irrigated wheat. Agron. J. 86: 100-107. [18] Munns, R. 2002. Comparative physiology of salt and water stress. Plant Cell Environ. 25: 239-250. [19] Muranaka, S., K. Shimizu, and M. Kato. 2002. Ionic and oxmotic efects of salinity on single-leaf photosynthesis in two wheat cultivars with diferent drought tolerance. Photosynthetica 40: 201-207. [20] Cosgrove D. 1993. Water uptake by growing cells an assessment of the controlling roles of wall relaxation, solute uptake, and hydraulic conductance. Int. J. Plant Sci. 154: 10-21. [21] Nazar, A.S.M.I., A. Paul, and S.K. Dutta. 1996. Frequency-dependent alteration of enolase activity by ELF ields. Bioelectrochemistry and Bioenergetics 39: 259-262. [22] Juma, N.G., and M.A. Tabatabai. 1988. Phosphatase activity in corn and soybean roots: conditions for assay and efects of metals. Plant and Soil 107: 39-47. [23] Pang, X.F. and B. Deng. 2008. Investigation of changes in properties of water under the action of a magnetic ield. Science in China Series G-Physics Mechanics Astron. 51: 1621-1632. [24] Cai, R., H. Yang, J. He, W. Zhu. 2009. he efects of magnetic ields on water molecular hydrogen bonds. J. Mol. Struct. 938: 15-19. [25] Pang, X. and B. Deng. 2010. Infrared absorption spectra of pure and magnetized water at elevated temperature. Europhys. Lett. 92: 65001. [26] Hosoda, H., H. Mori, N. Sogoshi, A. Nagasawa, and S. Nakabayashi. 2004. Refractive indices of water and aqueous electrolyte solutions under high magnetic ields. J. Phys. Chem. A. 108: 1461-1464 [27] Inaba, H., T. Saitou, K. Tozaki, and H. Hayashi. 2004. Efect of the magnetic ield on the melting transition of H2O and D2O measured by a high resolution and supersensitive diferential scanning calorimeter. J. Appl. Phys. 96: 6127-6132. [28] Chang, K.-T. and C.-I. Weng. 2008. An investigation into the structure of aqueous NaCl electrolyte solutions under magnetic ields. Comput. Mat. Sci. 43: 1048-1055. [29] Madsen, H.E.L. 2004. Crystallization of calcium carbonate in magnetic ield in ordinary and heavy water. J. Cryst. Growth 267: 251-255.
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