Alterations in Enzyme Activities in Leaves after Exposure of Plectranthus Sp. Plants to 900 MHZ Electromagnetic Field ELECTROMAGNETICFIELDSandELF
Materials and methods Plectranthus is the largest South African genus of plants
belonging to the mint family (Lamiaceae). There are many
Plectranthus species (around 44) that are currently used as
ornamental herbaceous plants throughout the world's gardens.
Several species are grown as leaf vegetables, as root
vegetables for their edible tubers, or as medicine. Plectranthus species are used as food plants by the larvae of
some Lepidoptera species.
Plants Plectrantus sp. were grown in a growing chamber
at controlled temperature (23–24°C), light (30–40 mmol m
–
2
s
–1
), humidity (60–65%) and photoperiod 12/12 h.
The exposure was performed by GSM mobile phone type
NSM-3, which was connected to a personal computer through
an interface cable. The mobile phone was programmed via
special software to emit carrier frequency 902 MHz (60
th
uplink channel of GSM900). The signal included standard
GSM modulation. GSM signal was pulsed. The duration of
the pulses was 577 microseconds that corresponded to one
time slot of TDMA frame. The TDMA frame in GSM
systems has a duration 4.615 milliseconds. Discontinuous
transmission mode (DTX) was off during all exposures.
Mobile phone pulse output power was 2 W. Plants were
exposed whole body to EM radiation from GSM mobile
phone at 20 cm distance from the antenna for 1 hour.
Alterations in enzyme activity in leaves were registered
immediately after the end of the exposure and 1, 2 and 24
hours later. At the same time control pots were kept at the
same conditions, but without exposure.
Glucose-6-phosphate dehydrogenase activity was
determined according to the method of Wakiuchi et al. (20).
This metod, as well as the methods for determination of
NADH-malate dehydrogenase and NADP-isocitrate
dehydrogenase activities are described in Handbook of Plant
Physiology (9). Protein quantity was determined according
to the method of Bradford (3).
The presented data are averages and standard deviations
of 6 measurements for each term. The Student t-test was used
to estimate the statistically significant differences between
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