|MadSci Network: Cell Biology|
Hi Belinda! The short answer is YES, magnetic fields do appear to have an effect on the growth of plants. However, we still don’t really understand how (the ‘mechanism’) magnetic fields affect plants. This is a very interesting question being explored by plant scientists and physicists, since plants are being exposed to low-level magnetic fields as a consequence of power lines and other industrial technology, but it is very far from being understood. Most of the research into this topic is published in Russian scientific journals, and are therefore difficult to locate, but are summarized in a review article by Belyavskaya (2004) in the journal Advances in Space Research (see reference below). The bibliography of that paper has many references that could be helpful to you. Weak electromagnetic fields (WEF) are generally thought to suppress the growth of plants and reduce cell division (arrest cells in G1 phase – the ‘growth phase’ leading up to cell division). A study by Sytnik et al. (1984) reported that the growth of wheat, pea, and sugar beet roots was significantly inhibited by WEF. In contrast, a study by Celestino and co-workers (2000) reported that weak electromagnetic fields (WEF) increase the germination of oak seeds (aka, acorns) and their subsequent growth (shoot length, dry weight). Similarly, Alexander and Doijode (1995) found that onion and rice seeds exposed to a WEF for 12 h showed significantly increased germination, shoot and root lengths, and fresh and dry weight of seedlings. M.V. Carbonell et al. (2000) confirmed that these low-frequency magnetic fields increase the germination rate and percentage of rice seeds. However, a study by Govoroon et al. (1992) observed no effect of WEF on the growth of pea, flax, and lentil seeds. These variable and contradictory results seem to suggest that the effects of magnetic fields on plants may be species-specific (e.g., stimulate growth certain plant species, inhibit growth in some species, and have no effect on others). Even though all of these studies use “weak electromagnetic fields”, the exact intensity of the magnetic field is also going to be an important variable. Levels of calcium (Ca++) inside of plant cells increases following exposure to magnetic fields, which is one of the proposed mechanisms by which magnetic fields may affect plants. Calcium ions (Ca++) participate in many plant growth processes and responses to stress (heat and salt stress, wounding, etc.). Another potential mechanism is being explored by NASA, which has done some research showing that magnetic fields may also affect the position of starch grains (aka amyloplasts) within plant cells, which will influence the direction of growth of the plant (a phenomenon called geotaxis). See: http://weboflife.nasa.gov/currentResearch/currentResearchFlight/sowingSeeds.htm There is much less information available for responses of algae to magnetic fields, since most research is focused on agriculturally important plants (beans, peas, wheat, etc.). Please e-mail me if you have any questions or confusions about what I have outlined here. Good luck! ~Shireef Darwish Belyavskaya, N.A. (2001). Ultrastructure and calcium balance in meristem cells of pea roots exposed to extremely low magnetic fields. Advanced Space Research, 28: 645–650. Govoroon, R.D., Danilov, V.I., Fomicheva, V.M., Belyavskaya, N.A., Zinchenko, S.Yu. Effects of fluctuations of a geomagnetic field and its screening on early phases in development of higher plants. Biofizika 37, 738–743, 1992 Sytnik, K.M., Kordym, E.L., Nedukha, E.M., Sidorenko, P.G.,Fomicheva, V.M. Plant Cell Under Alterations in Geophysical Factors, Naukova Dumka, Kiev, 1984. Alexander, M.P., and Doijode, S.D. (1995). Electromagnetic field, a novel tool to increase germination and seedling vigour of conserved onion (Allium cepa L.) and rice (Oryza sativa L.) seeds with low viability. Plant Genetic Resources Newsletter, 104: 1– 5. Hirota, N., Nakagawa, J., Kitazawa, K. (1999). Effects of a magnetic field on the germination of plants. Journal of Applied Physics, 85(8): 5717-5719. Aksyonov, S.I., Bulychev, A.A., Yu. Grunina, T., Goryachev, S.N., and Turovetsky, V.B. (2001). Effect of ELF-EMF treatment on wheat seedlings at different stages of germination and possible mechanisms of their origin. Electro- and Magnetobiology, 20(2): 231-253. Celestino, C., Picazo, M.L., and Toribio, M. (2000). Influence of chronic exposure to an electromagnetic field on germination and early growth of Quercus suber seeds: preliminary study. Electro- and Magnetobiology, 19(1): 115-120. Belyavskaya, N.A. (2004). Biological effects due to weak magnetic field on plants. Advances in Space Research, 34: 1566–1574. Carbonell, M.V., Martinez, E., and Amaya, J.M. (2000). Stimulation of germination in rice (Oryza sativa L.) by a static magnetic field. Electro- and Magnetobiology, 19(1): 121-128.
Try the links in the MadSci Library for more information on Cell Biology.