Studies on the effects of high frequency
electromagnetic stimulation on living beings have grown in number over the last few years, particularly in
relation to the exponential increase in use of cell phones among the general population. This
telecommunication device uses high frequency, non thermic electromagnetic waves (900–1800 MHz) coupled
with a lower frequency carrier (230 Hz). Shortly after the advent of cell phones, the question arose as to
whether this kind of radiation could constitute an environmental threat for living organisms, particularly in
relation to possible health effects. We chose to use tomato plants as our model biological system along with a
Mode Stirring Reverberation Chamber (MSRC) as the stimulating device. Plants offer numerous advantages
compared with animals (ease of growth, lack of mobility, absence of psychological side-effects), while the
MSRC allows us to generate a highly controlled and reproducible isotropic, homogeneous electromagnetic field.
Our investigation was focused at the molecular level, where we measured rapid changes in mRNA accumulation
(using qRT-PCR) of stress-related genes as molecular markers. We found that stress-related mRNAs such as
calmodulin, bZIP transcription factor and protein kinase strongly accumulate within minutes after a short (10
min), low amplitude (5 V/m), 900 MHz EMF stimulation. This accumulation does not occur if the plants are
placed into an EMF-proof container. Futhermore, exposure of a single leaf (while masking the rest of the
plant) shows that a traumatic signal rapidly moves from the stimulated leaf to the rest of the plant and
elicits accumulation of these same stress-related transcripts. In conclusion, we demonstrated that low
amplitude EMF stimulation constitutes an environmental stimulus able to activate stress-related genes in
tomato plants. |