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EMF radiations (1800 MHz)-inhibited early seedling growth of maize (Zea mays) involves alterations in starch and sucrose metabolism
Abstract
The present study investigated the impact of 1800-MHz electromagnetic field radiations (EMF-r), widely used in mobile communication, on the growth and activity of starch-, sucrose-, and phosphate-hydrolyzing enzymes in Zea mays seedlings. We exposed Z. mays to modulated continuous wave homogenous EMF-r at specific absorption rate (SAR) of 1.69±0.0 × 10(-1) W kg(-1) for ½, 1, 2, and 4 h. The analysis of seedlings after 7 days revealed that short-term exposure did not induce any significant change, while longer exposure of 4 h caused significant growth and biochemical alterations. There was a reduction in the root and coleoptile length with more pronounced effect on coleoptile growth (23 % reduction on 4-h exposure). The contents of photosynthetic pigments and total carbohydrates declined by 13 and 18 %, respectively, in 4-h exposure treatments compared to unexposed control. The activity of starch-hydrolyzing enzymes-α- and β-amylases-increased by ∼92 and 94 %, respectively, at an exposure duration of 4 h, over that in the control. In response to 4-h exposure treatment, the activity of sucrolytic enzymes-acid invertases and alkaline invertases-was increased by 88 and 266 %, whereas the specific activities of phosphohydrolytic enzymes (acid phosphatases and alkaline phosphatases) showed initial increase up to ≤2 h duration and then declined at >2 h exposure duration. The study concludes that EMF-r-inhibited seedling growth of Z. mays involves interference with starch and sucrose metabolism.
... When it is, higher SAR values were obtained in surface or inner tissue of organs with a low surface to volume ratio such as fruits or seeds: 0.8 to 1.050 W kg -1 in coconut fruit (Kundu et al. 2014), 0.05-0.17 W kg -1 in tomato fruit (Verma et al. 2020) and 0.169 W kg -1 in maize seeds (Kumar et al. 2016). In contrast, vegetative organs of soybean and rose plants displayed much lower SAR values of 3.9 9 10 -4 and 7.2 9 10 -4 W kg -1 for a field amplitude of 5.7 and 5.0 V m -1 , respectively (Halgamuge et al. 2015;Grémiaux et al. 2016) and 1.2-1.5 9 10 -3 W kg -1 in tomato seeds (Kumari et al. 2018), that are seeds with a low volume to surface ratio. ...
... This clearly supports the hypothesis that pre-formed tissue could perceive the EMF-r signal, store it, and later express it in tissues formed after exposure, as proposed by Thellier et al. (2000). It is, however, worth noting that numerous studies actually reveal very similar results, especially in those in which the authors exposed soaked seeds and looked for later morphological modifications (change in growth) on seedlings resulting from the exposure of the embryo at 900 MHz (Sharma et al. 2009(Sharma et al. , 2010Singh et al. 2012; Afzal and Mansoor 2012) and 1800 MHz (Chen and Chen 2014; Kumar et al. 2016). Similarly, EMF-r exposure (10.5-12.658 ...
... These authors also noticed that proteases, peroxidases and polyphenol oxidases were also considerably enhanced (Table 4) suggesting that the exposure actually induced an important change in plants metabolism. Invertases play a key role in maintaining osmotic pressure, cell differentiation and development, and are directly involved in modulating diverse abiotic stresses (Albacete et al. 2011) including EMF-r (Kumar et al. 2016). These last authors exposed plants to 1800 MHz (0.16 W kg -1 ) for 2 and 4 h and observed a significant reduction in carbohydrate content in Z. mays seedlings, along with increased activities in acid and alkaline invertases (88 and 266%, respectively) and aand b-amylases (about 90%), while starch phosphorylases and phophatases decreased (Table 4). ...
The technological advancement and increased usage of wireless and other communication devices have greatly enhanced the level of radiofrequency electromagnetic field radiation (EMF-r) in the environment. It has resulted in unprecedented increased exposure of living organisms to these radiations. Most of the studies in past have, however, focused on animal systems and comparatively less attention has been paid to plants with studies reporting various, sometimes contradictory effects. This review is an attempt to provide a critical appraisal of the available reports regarding the impacts of these radiations on plant development and the underlying physiological, biochemical, and molecular mechanisms involved. Here, we propose that the main entry point for the biological effects of EMF-r corresponds to an increase in ROS metabolism and cytosolic calcium that leads to various cellular responses including changes in gene expression and/or enzymatic activities, which could ultimately result in immediate cellular alterations or delayed plant growth. This may constitute a new perspective in the interpretation of plant responses to EMF-r exposure. Understanding the impacts of EMF-r and the inherent abilities of plants to cope up with such changes should lead to EMF-r being considered as full-fledged environmental signals that are perceived by the plants and integrated into their development patterns.
... Much concern is given to the effects of this radiation to human life and environmental health (Roux et al., 2006;Pietruszewski et al., 2007;Sheridan et al., 2010;Sharma and Parihar, 2014). Although plants constitute an outstanding model to study the effect of High Frequency nonionizing ElectroMagnetic Fields (HF-EMF) since their architecture (high surface area to volume ratio) optimises their interaction with the environment (Vian et al., 2016), limited concern was given to plant reactions (Ledoigt, 2006;Roux et al., 2006;Pietruszewski et al., 2007;Haggerty, 2010;Kumar et al., 2015) and only recently a few data became available, on the biomass production, leaf anatomy and tissue organization, overall, for two common species (Stefi et al., 2016(Stefi et al., , 2017. ...
... Proline, also measured as a biomarker of abiotic stress and the catalase enzyme activity were all increased as a result of exposure to the electromagnetic field (EMF). EMF at 1200 MHz was also reported to inhibit early seedling growth in Z. mays, causing alterations in starch and sucrose metabolism (Kumar et al., 2015). Moreover chromosomal aberrations were observed in root tip cells of Z. mays induced by 900 MHz RF radiation (Rȃcuciu, 2009) while exposure times between one and eight hours, at 1 GHz radiation, on Z. mays seeds, have disruptive effects on plantlets developed from exposed seeds, regarding the young plant growth, photo-assimilatory pigments and nucleic acids contents (Rȃcuciu et al., 2015). ...
... Proline content is also increased, significantly, in exposed plants (940 MHz) which is also considered to be a plant response against exposure. Moreover, recent reports indicate that electromagnetic field (EMF) at 1200 MHz inhibits early seedling growth in Z. mays, causing alterations in starch and sucrose metabolism (Kumar et al., 2015). ...
A series of experiments was carried out to investigate possible structural or biochemical effects on young Zea mays plants after a long-term exposure to non-ionizing, continuous radiation emitted from the base unit of a cordless DECT system. Exposed plants, compared to their normal counterparts, do not seem to be affected concerning their sprouting potential, biomass production for both the above ground part and the root, leaf structure, photosynthetic pigment content and their absorbance. The structural profile of the exposed plants seems almost identical to those of the control ones. Biomass production, photosynthetic pigments, leaf structure and chloroplast arrangement do not differ in exposed plants. What seems to be affected is the structure of the chloroplasts accommodated in the bundle sheath cells of the exposed leaves. They suffer a slight swelling of their thylakoids and an undulation of some of the thylakoid membranes. Scarcely a disruption of chloroplast envelope can be observed.
... It is not yet known if the decrease in protein content results from an increase in protein degradation and/or a decrease in protein synthesis, but this may constitute a stimulating field of investigation, since evidence shows that mRNA selection from translation occurs after plant exposure to HF-EMF [10]. Hydrolytic enzymatic activities ( -and -amylases and invertases) responsible for the production of soluble sugar increase in germinating seeds after exposure to HF-EMF [12,28,32], while the starch phosphorylase activity, phosphorolytic and potentially reversible, is diminished. In contrast, HF-EMF exposure causes a drop of soluble sugar that may be related to the inhibition of Krebs cycle and pentose phosphate pathway in Plectranthus (Lamiaceae) leaves after exposure to 900 MHz EMF [29], suggesting that seeds and adult leaves respond in a different way to HF-EMF exposure. ...
... Seed exposure to EMF generally results in a reduced germination rate [27,37,39], while in other cases germination is unaffected [42] or even stimulated [16]. The seedlings issued from EMF-exposed seeds displayed reduced growth of roots and/or stem [13,28,32,[37][38][39]41] but rarely a stimulatory effect [16]. This point strongly differs from exposure to static magnetic fields or extremely low frequency EMF, in which the stimulatory effects on growth are largely predominant [54]. ...
... These different effects of PEMF compared to HF-EMF on plants may be related to their fundamental difference in terms of physical properties. Exposure to HF-EMF of seedlings or plants (rather than seeds) also generally resulted in growth inhibition [9,18,27,28,39]. Singh et al. [7] showed that rhizogenesis (root number and length) is severely affected in mung bean after exposure to cell phone radiation, possibly through the activation of several stress-related enzymes (peroxidases and polyphenol oxidases). ...
High frequency nonionizing electromagnetic fields (HF-EMF) that are increasingly present in the environment constitute a genuine environmental stimulus able to evoke specific responses in plants that share many similarities with those observed after a stressful treatment. Plants constitute an outstanding model to study such interactions since their architecture (high surface area to volume ratio) optimizes their interaction with the environment. In the present review, after identifying the main exposure devices (transverse and gigahertz electromagnetic cells, wave guide, and mode stirred reverberating chamber) and general physics laws that govern EMF interactions with plants, we illustrate some of the observed responses after exposure to HF-EMF at the cellular, molecular, and whole plant scale. Indeed, numerous metabolic activities (reactive oxygen species metabolism,
α
- and
β
-amylase, Krebs cycle, pentose phosphate pathway, chlorophyll content, terpene emission, etc.) are modified, gene expression altered (calmodulin, calcium-dependent protein kinase, and proteinase inhibitor), and growth reduced (stem elongation and dry weight) after low power (i.e., nonthermal) HF-EMF exposure. These changes occur not only in the tissues directly exposed but also systemically in distant tissues. While the long-term impact of these metabolic changes remains largely unknown, we propose to consider nonionizing HF-EMF radiation as a noninjurious, genuine environmental factor that readily evokes changes in plant metabolism.
... Z. mays plants exposed to modulated continuous wave homogenous MF at specific absorption rate (SAR) of 1.69 ± 0.0 × 10 −1 W kg −1 for A1/2, 1, 2, and 4 h for 7 days revealed that short-term exposure did not induce any significant change, while longer exposure of 4 h caused significant growth and biochemical alterations. Maize plants showed a reduction in the root and coleoptile length with more pronounced effect on coleoptile growth (23% reduction on 4 h exposure) (Kumar et al., 2016). ...
... The contents of maize photosynthetic pigments and total carbohydrates declined by 13% and 18%, respectively, in 4 h exposure treatments to increased MF compared to unexposed control (Kumar et al., 2016). Furthermore, the activity of starch-hydrolyzing enzymes αand β-amylases increased by similar to 92% and 94%, respectively, at an exposure duration of 4 h, over that in the control. ...
... In response to 4 h exposure treatment, the activity of sucrolytic enzymes acid invertases and alkaline invertases increased by 88% and 266%, whereas the specific activities of phosphohydrolytic enzymes (acid phosphatases and alkaline phosphatases) showed initial increase and then declined at >2 h exposure duration. The results of this study indicate MF inhibited seedling growth of Z. mays by interfering with starch and sucrose metabolism (Kumar et al., 2016). ...
This chapter summarizes some of the most important information of plant responses to magnetic fields (MF), with particular reference to:
Effects of Low MF on Plant Development
Effects of Low MF on Transition to Flowering
Effects of High MF on Germination
Effects of High MF on Cryptochrome
Effects of High MF on Roots and Shoots
Effects of High MF on Gravitropic Responses
Effects of High MF on Redox Status
Effects of High MF on Photosynthesis
Effects of High MF on Lipid Composition
Other Effects of High MF on Plants
Possible Mechanisms of Magnetoreception
... All research groups have either used cell phone and simulators in their studies. The monocot plant species used are, for example, duckweed (Tkalec et al. 2005(Tkalec et al. , 2007, onion (Tkalec et al. 2009;Pesnya and Romanovsky 2013), wheat Hussein and El-Maghraby 2014) and maize (Zare et al. 2015a, b, c;Kumar et al. 2015;Racuciu et al. 2014). They have been irradiated for different time intervals (0.03-48 h) using various radiation frequencies and strengths. ...
... Root-shoot lengths are first biometric responses, which need to taken into account in plants grown in stressful conditions. Different parameters such as exposure time, dose and mode have been considered in various studies (Tkalec et al. 2005;Afzal and Mansoor 2012;Hussein and El-Maghraby 2014;Racuciu et al. 2014;Kumar et al. 2015; Decline in PPX activity at low field strength and vice versa. Also four different PPX isoenzymes (two slow and two fast migrating) were detected but no differences in their isoenzyme pattern in both exposed and control plants. ...
... In contrast to higher field strength, lower field amplitude (10 Vm −1 ) and longer duration (14 h) caused no inhibition in growth. Similar growth decline was found in maize by Racuciu et al. (2014) and Kumar et al. (2015) when exposure was performed for longer duration. They collectively noted significant growth inhibition of root, coleoptile and total chlorophyll contents. ...
Since last decade, GSM (Global System for Mobile Communication) technology has evidently revolutionized our digital world. It uses electromagnetic frequency radiations (EMFr), ranging 850–1900 MHz, and is being composed of three main units (i.e., mobile station, access and core networks). GSM technology has significant impact on our daily life as revealed by increased number of mobile users in the world over. The main goal of the present review is to critically revisit the available literature regarding the responses of various flowering plant species towards GSM and GSM-like radiations using physiological, biochemical, molecular and cytological markers using in vitro approaches. Different monocots (tomato, onion, wheat and maize etc.) and dicots (pulses, mustard and flax) have been studied using both GSM mobile phone and GSM simulators. Different studies revealed overall reductions in germination, root-shoot lengths, dry weight, in both dose and time-dependent manners. However, there could be found incline in various parameters at biochemical and molecular levels. Furthermore, there could be found disturbances at cytological levels upon exposure of roots of onion to EMFr radiations. The overall literature review shows the negative effects of GSM and GSM-like radiations on targeted plant species. In order to alleviate the stressful effects of EMFr radiations on plants, in vivo studies need to be done using various cost-effective approaches such as use of biochar and various organic amendments.
... In particular, it was found that exposure of maize (Zea mays L.) seeds to 1 GHz electromagnetic field inside a transverse electromagnetic cell for 1-8 hours led to inhibition of photo-assimilatory pigments level in 12-day seedlings grown from exposed seeds (Răcuciu et al., 2015). Kumar et al. (2015) showed a 13 % decrease in total chlorophyll content after 4 h exposure of maize seedlings to 1800 MHz (332 mW·m −2 ). These modifications may be related to abnormal photosynthetic activity, which relies on many parameters, including chlorophylls' and carotenoids' content. ...
... Effects of the Wi-Fi and experimental gadget M4 on wheat (Kumar et al., 2015). In our studies, the content of chlorophyll a was the most tolerant to EMF of the Wi-Fi router and decreased by 9 % only. ...
Objectives. To assess the effects of the electromagnetic field of a Wi-Fi system and the experimental gadget M4 developed by SAS “IRDT” (France) on wheat seed germination, growth and photosynthetic activity of juvenile plants. Material and methods. The test-plants were grown under controlled conditions of light, temperature and humidity for 8 days in a pot experiment modeling the following treatments: (1) the absence of electromagnetic field of Wi-Fi systems (control); (2) at a distance of 30 cm from the operating Wi-Fi router; (3) at a distance of 30 cm from operating Wi-Fi router and the experimental gadget M4. The test plant development and vitality were assessed using indices of seed germination, growth rates (shoot height, root length, number of lateral roots, shoot and root dry weights), photosynthetic pigment content in leaves and the number of chloroploplasts per a mesophyll cell in foliar tissues. Results. It was found that the electromagnetic field of Wi-Fi router initially stimulated, but then suppressed the germination of seeds, reduced the growth of shoots and roots, the content of photosynthetic pigments and chloroplastogenesis in the mesophyll tissues in leaves of wheat juvenile plants. The root length was the most sensitive morphometric parameter to the electromagnetic field of Wi-Fi router. The use of the gadget M4 completely compensated the negative impact of Wi-Fi router on the seed germination, shoots growth, and partially compensated for the suppression of root growth, chloroplastogenesis, chlorophyll a and b content in wheat leaves. Conclusion. The attenuation effect of gadget M4 against the damaging effect of electromagnetic fields of anthropogenic origin is promising and further investigations are required to observe the effects on long term, from sowing to maturity, including the next generation of seeds.
... Electromagnetic radiation (1800 MHz) interferes with carbohydrate metabolism and inhibits the growth of Zea mays (Kumar et al., 2015). Furthermore, cell phone electromagnetic radiation inhibits root growth of the mung bean (Vigna radiata) by inducing ROS-generated oxidative stress despite increased activities of antioxidant enzymes (Sharma et al., 2009). ...
... Once the problem becomes evident, the guidelines of radiation emitted by the antennas should be reviewed. Proper risk assessment of electromagnetic radiation should be undertaken to develop management strategies for reducing this pollution in the natural environment (Kumar et al., 2015). ...
In the last two decades, the deployment of phone masts around the world has taken place and, for many years, there has been a discussion in the scientific community about the possible environmental impact from mobile phone base stations. Trees have several advantages over animals as experimental subjects and the aim of this study was to verify whether there is a connection between unusual (generally unilateral) tree damage and radiofrequency exposure. To achieve this, a detailed long-term (2006-2015) field monitoring study was performed in the cities of Bamberg and Hallstadt (Germany). During monitoring, observations and photographic recordings of unusual or unexplainable tree damage were taken, alongside the measurement of electromagnetic radiation. In 2015 measurements of RF-EMF (Radiofrequency Electromagnetic Fields) were carried out. A polygon spanning both cities was chosen as the study site, where 144 measurements of the radiofrequency of electromagnetic fields were taken at a height of 1.5m in streets and parks at different locations. By interpolation of the 144 measurement points, we were able to compile an electromagnetic map of the power flux density in Bamberg and Hallstadt. We selected 60 damaged trees, in addition to 30 randomly selected trees and 30 trees in low radiation areas (n=120) in this polygon. The measurements of all trees revealed significant differences between the damaged side facing a phone mast and the opposite side, as well as differences between the exposed side of damaged trees and all other groups of trees in both sides. Thus, we found that side differences in measured values of power flux density corresponded to side differences in damage. The 30 selected trees in low radiation areas (no visual contact to any phone mast and power flux density under 50μW/m(2)) showed no damage. Statistical analysis demonstrated that electromagnetic radiation from mobile phone masts is harmful for trees. These results are consistent with the fact that damage afflicted on trees by mobile phone towers usually start on one side, extending to the whole tree over time.
http://kompetenzinitiative.net/KIT/KIT/baeume-in-bamberg/
http://kompetenzinitiative.net/KIT/wp-content/uploads/2016/09/Trees-in-Bamberg-and-Hallstadt-Documentation-2006-2016.pdf
https://groups.google.com/forum/#!topic/mobilfunk_newsletter/5r37cJ-EqPI
... Notwithstanding, there are a few reports demonstrating the positive impacts in plants (Jinapang et al. 2010;Bulak et al. 2018). EMF-r affect plants at morphological (Cretescu et al. 2013;Stefi et al. 2017), physiological (Kumar et al. 2016), biochemical (Singh et al. 2012), and molecular (Roux et al. 2008) levels. EMF-r have also been documented to alter the oxidative metabolism in plants (Sharma et al. 2009;Chandel et al. 2017). ...
... Mobile phones use electromagnetic radiation in the microwave range (450-3800 MHz and 24-80 GHz in 5G mobile). In the past, several studies have investigated the effect of 450-1800 MHz EMF-r in plants (Tkalec et al. 2005;Roux et al. 2008;Sharma et al. 2009;Gustavino et al. 2016;Kumar et al. 2016). However, not much has been done to unravel the biological effects, including the cyto-and genotoxic effects, of 2100 MHz EMF-r in plant systems. ...
The present study evaluated the potential of 2100 MHz radiofrequency radiations to act as cytotoxic and genotoxic agent. Fresh onion (Allium cepa L.) roots were exposed to electromagnetic field radiations (EMF-r) for different durations (1 h and 4 h) and evaluated for mitotic index (MI), phase index, chromosomal aberrations, and DNA damage. DNA damage was investigated with the help of the comet assay by assessing various parameters like % head DNA (HDNA), % tail DNA (TDNA), tail moment (TM), and olive tail moment (OTM). Effects of EMF-r exposure were also compared with that of methyl methanesulfonate (MMS; 90 μM), which acted as a positive control. The post-exposure effects of EMF-r after providing the test plants with an acclimatization period of 24 h were also evaluated. Compared to the control, a significant increase in the MI and aberration percentage was recorded upon 4 h of exposure. However, no specific trend of phase index in response to exposure was detected. EMF-r exposure incited DNA damage with a significant decrease in HDNA accompanied by an increase in TDNA upon exposure of 4 h. However, TM and OTM did not change significantly upon exposure as compared to that of control. Analysis of the post-exposure effects of EMF-r did not show any significant change/recovery. Our data, thus, suggest the potential cytotoxic and genotoxic nature of 2100 MHz EMF-r. Our study bears great significance in view of the swiftly emergent EMF-r in the surrounding environment and their potential for inciting aberrations at the chromosomal level, thus posing a genetic hazard.
... For the EMF-r treatment, we followed the methodology of Kumar et al. [22] with some modifications. We exposed the test plants to EMF-r using Agilent N9310A radio frequency signal generator (Keysight Technologies, USA) connected to a power amplifier (ZHL-5 W-2GX+; Minicircuits, USA) and a power supply. ...
... Exploring the literature regarding the biological effects of EMF-r revealed indecisive conclusions, as few studies have reported negative implications of EMF-r [22,27] while, other few stated no or positive effects [28,29]. The present study thus tried to inspect the cyto-and genotoxic potential of 2350 MHz EMF-r using A. cepa as the test plant. ...
Background:
The exponential increase of electromagnetic field radiations (EMF-r) in the natural environment has raked up the controversies regarding their biological effects. Concern regarding the putative capacity of EMF-r to affect living beings has been growing due to the ongoing elevation in the use of high frequency EMF-r in communication systems, e.g. Mobile phones.
Methods:
In the present study, we tried to examine the cyto- and genotoxic potential of mobile phone EMF-r at 2350 MHz using onions (Allium cepa L.). Fresh adventitious onion roots were exposed to continuous EMF-r at 2350 MHz for different time periods (1 h, 2 h and 4 h). The evaluation of cytotoxicity was done in terms of mitotic index (MI), phase index and chromosomal aberrations. Genotoxicity was investigated employing comet assay in terms of changes in % HDNA (head DNA) and % TDNA (tail DNA), TM (tail moment) and OTM (olive tail moment). Data were analyzed using one-way ANOVA and mean values were separated using post hoc Tukey's test.
Results:
The results manifested a significant increase of MI and chromosomal aberrations (%) upon 4 h, and ≥ 2 h of exposure, respectively, as compared to the control. No specific changes in phase index in response to EMF-r exposure were observed. The % HDNA and % TDNA values exhibited significant changes in contrast to that of control upon 2 h and 4 h of exposure, respectively. However, TM and OTM did not change significantly.
Conclusions:
Our results infer that continuous exposures of radiofrequency EMF-r (2350 MHz) for long durations have a potential of inciting cyto- and genotoxic effects in onion root meristems.
... However, the chlorophyll content declined with a further increase in exposure time, indicating that a longer duration of exposure is detrimental to chlorophyll content in plants. A study on maize seedlings also reported that a 4 h exposure to 1800 MHz (power density 332 ± 10.36 mW/m 2 ; SAR 1.69 W/kg) EMF significantly hampered root and coleoptiles development as well as the chlorophyll content of seedlings (Kumar et al., 2016). Such decline in chlorophyll content was similar to that observed in salt, drought and temperature stresses (Ashraf and Harris, 2013) induced by impaired biosynthesis or accelerated pigment degradation. ...
... proteases, a-amylase, β-amylase, polyphenoloxidases and peroxidases in EMF-exposed radicles. Similar observations were reported in maize seedlings (Kumar et al., 2016) in which a 1800 MHz EMF exposure led to a significantly increased activity of α-amylase, β-amylase and invertase, and a reduced activity of starch phosphorylase, the effects being higher with an increase in the exposure duration. The results indicate that stress induced by mobile phone RF-EMF exposure in plants leads to the hyperaccumulation of these stress-related enzymes and alters the normal enzymatic levels in plants. ...
... Much concern is given to the effects of this radiation to human life and environmental health (Roux et al., 2006;Pietruszewski et al., 2007;Sheridan et al., 2010;Sharma and Parihar, 2014). Although plants constitute an outstanding model to study the effect of High Frequency non-ionizing Electromagnetic Fields (HF-EMF) since their architecture (high surface area to volume ratio) optimizes their interaction with the environment (Vian, et al. 2016), limited concern was given to plant reactions (Ledoigt, 2006;Roux et al., 2006;Pietruszewski et al., 2007;Haggerty, 2010;Kumar et al., 2015). Recently some data became available, on the biomass production, leaf anatomy and tissue organization, overall, for two widely used dicotyledonsthe delicate, short-living, Arabidopsis thaliana (L.) Heynh, (Stefi et al., 2016) as a major experimental model plant and Gossypium hirsutum L. (upland cotton) as a widely cultivated crop plant of great economic importance (Stefi et al., 2017a) after their long term exposure to non-ionizing, DECT emitted radiation. ...
... Recent investigations revealed that the reduction of fresh weight and biomass is something common in plants suffering long term exposure to non-ionizing radiation (Sharma et al., 2009;Kumar et al., 2015;Stefi et al., 2016Stefi et al., , 2017aStefi et al., , 2017b. The same seems to apply to P. halepensis as well, since the fresh weight and, consequently, the biomass are strongly reduced in both the shoots and the roots of the exposed plants. ...
... Much concern is given to the effects of this radiation to human life and environmental health (Roux et al., 2006;Pietruszewski et al., 2007;Sheridan et al., 2010;Sharma and Parihar, 2014). Some concern was given to plant reactions (Ledoigt, 2006;Haggerty, 2010;Kumar et al., 2015) yet only a few data is available on the biomass production, leaf anatomy and tissue organization, overall for a single species. In this paper we present a complete series of data for a single species, Arabidopsis thaliana (Col.), cultured under controlled conditions in specially designed ...
A series of experiments was carried out to investigate any structural or biochemical alterations on Arabidopsis thaliana (Col.) plants after a long term exposure to non ionizing radiation emitted from the base unit of a cordless DECT system. Exposed plants, compared to their control counterparts, seem to be affected concerning their biomass and leaf structure. Their leaves are thinner and possess fewer chloroplasts. SEM observations of the exposed leaves reveal that the only feature affected is the pubescence which almost disappears while TEM investigation revealed minor structural effects in the chloroplasts. The reduction in the number of chloroplasts as well as the decrease of stroma thylakoids and photosynthetic pigments are probably the main reasons for a weak photosynthetic potential and a consequent reduction of the biomass production.
... The RF-EMF radiation is identified to have a biological effect on living organisms, and research over the many years has shown that the biological processes in living organisms are more responsive to low-intensity radiation (Bolen, 1988). Investigations in the field of effects of the weak RF-EMFs and radiation have focused on animals (Eberhardt et al., 2008;Finnie et al., 2009;Gannes et al., 2009;Hirota et al., 2009;Masuda et al., 2009;Nittby et al., 2011;Tang et al., 2015), plants (Gremiaux et al., 2016;Gustavino et al., 2016;Halgamuge et al., 2015;Kumar et al., 2015;Senavirathna et al., 2014a, b), epidemiological evidence (Benson et al., 2013;Hardell et al., 2005Hardell et al., , 2009Johansen et al., 2001;Linet et al., 2006;Schüz et al., 2006), children (Elliott et al., 2010;Li et al., 2012;Sudan et al., 2013a, b), human sleep research (Arnetz et al., 2007;Danker-Hopfe et al., 2010, 2015Leitgeb et al., 2008;Loughran et al., 2012;Lowden et al., 2011;Regel et al., 2007) and cell cultures (Hook et al., 2004;Kazemi et al., 2015;Kim et al., 2015;Koyama et al., 2015;Liu et al., 2015). Many types of research used 900 MHz (Cucurachi et al., 2016;Senavirathna and Takashi, 2014) as 900 MHz frequencies are utilized in GSM technology. ...
Aim:
The aim of this article was to explore the hypothesis that non-thermal, weak, radiofrequency electromagnetic fields (RF-EMF) have an effect on living plants.
Subject and methods:
In this study, we performed an analysis of the data extracted from the 45 peer-reviewed scientific publications (1996-2016) describing 169 experimental observations to detect the physiological and morphological changes in plants due to the non-thermal RF-EMF effects from mobile phone radiation. Twenty-nine different species of plants were considered in this work.
Results:
Our analysis demonstrates that the data from a substantial amount of the studies on RF-EMFs from mobile phones show physiological and/or morphological effects (89.9%, p < 0.001). Additionally, our analysis of the results from these reported studies demonstrates that the maize, roselle, pea, fenugreek, duckweeds, tomato, onions and mungbean plants seem to be very sensitive to RF-EMFs. Our findings also suggest that plants seem to be more responsive to certain frequencies, especially the frequencies between (i) 800 and 1500 MHz (p < 0.0001), (ii) 1500 and 2400 MHz (p < 0.0001) and (iii) 3500 and 8000 MHz (p = 0.0161).
Conclusion:
The available literature on the effect of RF-EMFs on plants to date observed the significant trend of radiofrequency radiation influence on plants. Hence, this study provides new evidence supporting our hypothesis. Nonetheless, this endorses the need for more experiments to observe the effects of RF-EMFs, especially for the longer exposure durations, using the whole organisms. The above observation agrees with our earlier study, in that it supported that it is not a well-grounded method to characterize biological effects without considering the exposure duration. Nevertheless, none of these findings can be directly associated with human; however, on the other hand, this cannot be excluded, as it can impact the human welfare and health, either directly or indirectly, due to their complexity and varied effects (calcium metabolism, stress proteins, etc.). This study should be useful as a reference for researchers conducting epidemiological studies and the long-term experiments, using whole organisms, to observe the effects of RF-EMFs.
... 48 h laptop exposure has the most negative effect with 17% germination as compared to negative control with 67% germination. Present results are consistent with Racuciu et al. (2015) and Kumar et al. (2015) who reported electromagnetic radiation of mobile phone induced root and coleoptiles growth inhibition in Zea mays and Cammaerts and Johansson (2015) in Lepidium sativum. Possible reasons for reduced growth observed by these researchers were retarded in chlorophyll pigments and nucleic acid content, interference in starch and sucrose metabolism and lack of imbibitions by germinal cells. ...
... También se demostró que las plantas de maíz al ser expuestas a 940 Mhz tuvieron un incremento en la concentración de malondialdehido así como de la actividad catalasa, siendo ambos indicadores de peroxidación (Zare et al., 2015). Paralelamente, se ha demostrado un retraso en la germinación de semillas de maíz, explicado por la alteración en el contenido de almidón de las mismas, así como un efecto sobre el metabolismo de la sacarosa (Kumar et al., 2016). ...
A study was done on the effects and influence of conventional electromagnetic fields (Wifi and Cellular) on contaminating microorganisms. The study was performed using Luria-Bertani (LB) and Water Peptone 2.5% (WP) media in two Wifi band channels (1 and 11) using control samples in each case, for a period of 2 days at -30 dBm. The results show a significant decrease in the viability of Escherichia coli ATCC25922 over WP. However, no significant changes were found when LB was used; both results are repeated for both channels. This generates possible anti-pollution technologies for the food industry using electromagnetic fields as the operating principle.
... También se demostró que las plantas de maíz al ser expuestas a 940 Mhz tuvieron un incremento en la concentración de malondialdehido así como de la actividad catalasa, siendo ambos indicadores de peroxidación (Zare et al., 2015). Paralelamente, se ha demostrado un retraso en la germinación de semillas de maíz, explicado por la alteración en el contenido de almidón de las mismas, así como un efecto sobre el metabolismo de la sacarosa (Kumar et al., 2016). ...
The mainstreaming efforts of the LabSim and LAMAP research laboratories of the Technology Faculty led to the study of the effects and influence of conventional electromagnetic fields (Wifi and Cellular) on contaminating microorganisms. The study was performed using Luria-Bertani (LB) and Water Peptone 2.5% (WP) media in two Wifi band channels (1 and 11) using control samples in each case, for a period of 2 days at -30 dBm. The results show a significant decrease in the viability of Escherichia coli ATCC25922 over WP, however, no significant changes were found when LB was used, both results are repeated for both channels. This generates possible anti-pollution technologies for the food industry using electromagnetic fields as the operating principle.
... During the previous century and currently, several researchers have investigated the effects of electromagnetic radiation on plants, both in the laboratory (Harte, 1950(Harte, , 1972Jerman et al., 1998;Lerchl et al., 2000;Sandu et al., 2005;Roux et al., 2006;Pietruszewski et al., 2007;Tkalec et al., 2005Tkalec et al., , 2009Beaubois et al., 2007;Haggerty, 2010;Pesnya and Romanovsky, 2013;Sharma and Parihar 2014;Cammaerts and Johansson, 2015;Kumar et al., 2015;Stefi et al., 2016Stefi et al., , 2017aStefi et al., , 2017b, and on the field (Bernatzky, 1986;Volkrodt, 1987Volkrodt, , 1991Selga and Selga, 1996;Balodis et al., 1996;Haggerty, 2010). For both types of studies, most of the times, detrimental effects have been reported, even for weak radiation exposure (Halgamuge, 2017). ...
Mobile phones turned to be the most common form of public communication. Therefore, life on our planet continues wrapped in a “cloud” of non-ionizing radiations. Myrtus communis L. is an evergreen shrub, common in Mediterranean formations, exposed and adapted to two seasonally separated and qualitatively different environmental stresses. Thus, we considered it important to investigate the response of this tolerant species to emitted GSM non-ionizing radiations and compare it to already available data from thoroughly investigated plant species. Although the leaves of the exposed plants present unaffected tissue arrangement, their mesophyll cells accumulate large amounts of secondary metabolites, their photosynthetic pigments are dramatically reduced, the ROS counted are significantly increased and the presence of DDC, which cannot be detected in the leaves of the control plants, is recorded in high levels. The exposed leaves seem to experience a severe oxidative stress which probably induces DDC expression and the biosynthesis of the neurotransmitter dopamine, the activation of the shikimate pathway and, eventually, the accumulation of secondary metabolites.
... Since the effective resistance of cell membrane has been inversely correlated to frequency (Lvovich, 2012), therefore, the greater damage to cells and tissues was observed at 1800 MHz than at 900 MHz. Previously, studies demonstrated that EMF-r and cell phone radiations inhibit root growth, alter biochemical processes, and induce free radical-mediated oxidative damage (Tkalec et al., 2005(Tkalec et al., , 2009Sharma et al., 2009;Singh et al., 2012;Kumar et al., 2016;Chandel et al., 2017). In our study, we observed that roots were thickened upon exposure to EMF-r. ...
... The results showed ( Table 1) that, in individual treatments of EMF, mean values of length of plants, leaves number and biomass of mung bean seedling were decreased as compared to control. Similarly, the gradual pronounced decrease observed in growth and biomass in higher concentration of cadmium and lead (750mm) (p<0.001) ( Kumar et al., (2016) concluded that a considerable decrease in coleoptile growth of Zea mays. Also our results similar with the results of Sharma et al., (2009) and Halgamuge and Eberhardt (2015) who observed a reduction in germination rate in seeds of soya bean and mung bean respectively. ...
The present study deals with the individual and combined effect of heavy metals and EMF. The treatments include
different concentrations of lead and cadmium (250mm, 500mm and 750mm) which are selected as higher than permissible
limits and other is an electromagnetic field (EMF). The effect of these stresses studied on the length of plant, the leaves
number, biomass of plant and accumulation of lead and cadmium contents in mung bean seedlings (Vigna radiata). The
results showed 500 and 750mm of lead and cadmium significantly decline plant height, the number of leaves and whole
plant fresh and dry weight as in order (Cd 750mm> Cd 500mm>Pb750mm>Pb500mm), but a slight suppressed in all
developing parameters and weight when exposed by EMF. Whereas, the combined treatment of lead+EMF and
cadmium+EMF i.e 750mmCd +EMF>750mmPb + EMF cause a considerable decline in growth parameter and biomass of
mung bean. In mung bean sequence of accumulation of lead and cadmium functioning as Cd 750mm> Cd 750mm EMF> Cd
500mm> Pb 750mm EMF> Pb 750mm. This significant building up of lead and cadmium content under single and
combined treatment affected the growth factors of mung bean seedlings.
Key words: Electromagnetic field, Lead (Pb), Cadmium (Cd), Milimolal (mm), BDL (below detectable limits).
... 48 h laptop exposure has the most negative effect with 17% germination as compared to negative control with 67% germination. Present results are consistent with Racuciu et al. (2015) and Kumar et al. (2015) who reported electromagnetic radiation of mobile phone induced root and coleoptiles growth inhibition in Zea mays and Cammaerts and Johansson (2015) in Lepidium sativum. Possible reasons for reduced growth observed by these researchers were retarded in chlorophyll pigments and nucleic acid content, interference in starch and sucrose metabolism and lack of imbibitions by germinal cells. ...
Present study was under taken to predict the possible DNA damages (Genotoxicity) and carcinogenicity caused by Radio frequency radiations (R.F.) to living tissue. Dry seeds of Chickpea were treated with GSM cell phone (900 MHz) and laptop (3.31 GHz) as R.F. source for 24 and 48 hours. Untreated seeds were used as (0 hours) negative control and Gamma rays (250 Grey) as positive control. Plant chromosomal aberration assay was used as genotoxicity marker. All the treatment of R.F. inhibits seed germination percentage. 48 hours laptop treatment has the most negative effect as compared to untreated control. A decrease was observed in Mitotic index (M.I) and increase in Abnormality index (A.I) with the increase in exposure duration and frequency in (Hz). Cell membrane damages were also observed only in 48 hour exposure of cell phone and laptop (R.F.). Maximum nuclear membrane damages and ghost cells were again recorded in 48 hour exposure of cell phone and laptop. The radiofrequency radiations (900 MHz and 3.31GHz) are only genotoxic as they induce micronuclei, Bi-nuclei, multi-nuclei and scattered nuclei but could be carcinogenic as 48 hour incubation of R.F. induced fragmentation and ghost cells. Therefore cell phones and laptop should not be used unnecessarily to avoid possible genotoxic and carcinogenic effects.
Main conclusion:
Although exposure to low frequency electromagnetic radiation is harmful to plants, LF-EM irradiated Nerium oleander seedlings exhibited enhanced development and growth, probably taking advantage of defined structural leaf deformations. Currently, evidence supports the undesirable, often destructive impact of low frequency electromagnetic (LF-EM) radiation on plants. The response of plants to LF-EM radiation often entails induction in the biosynthesis of secondary metabolites, a subject matter that is well documented. Nerium oleander is a Mediterranean plant species, which evolved remarkable resistance to various environmental stress conditions. In the current investigation, cultivated N. oleander plants, following their long-term exposure to LF-EM radiation, exhibited major structural modifications as the flattening of crypts, the elimination of trichomes and the reduction of the layers of the epidermal cells. These changes co-existed with an oxidative stress response manifested by a significant increase in reactive oxygen species at both the roots and the above ground parts, a decline in the absorbance of light by photosynthetic pigments and the substantially increased biosynthesis of L-Dopa decarboxylase (DDC), an enzyme catalyzing the production of secondary metabolites that alleviate stress. The exposed plants exhibited greater primary plant productivity, despite a manifested photosynthetic pigment limitation and the severe oxidative stress. This unique response of N. oleander to severe abiotic stress conditions may be owed to the advantage offered by a structural change consistent to an easier diffusion of CO2 within the leaves. A major plant response to an emerging "pollutant" was documented.
In this study, the effects of electromagnetic waves emitted from mobile phones operating at 1800 MHz were investigated on germination, root growth and mitotic division of root tips of Lens culinaris Medik. Seeds were split into three groups. The first group was exposed to a mobile phone electromagnetic field for 48 hours at the state of dormancy, and the second group was exposed to the same electromagnetic field at the state of division. The third group, the control group, was not exposed to an electromagnetic field beyond the natural background. The results obtained in the study indicate that electromagnetic waves emitted from mobile phones affect seeds in the state of dormancy more than the state of germination. Germination rate was not affected under the specified exposure conditions, but root growth decreased due to a possible effect of oxidative stress in the state of dormant seeds. There was also a noticeable increment in the c-mitosis rates, especially in the state of dormant seeds. The reason for this increment could be problems in spindle function.
The aim of this study was to investigate the effects of 900 and 1800 MHz electromagnetic field (EMF) emitted by base station antennas implementing the mobile telephone communication on electrocardiogram (ECG) and some biochemical parameters. Animal material was consisted of 26 male guinea pigs, weighing 652±22.8 g in average. Animals were divided into three groups, as group 1 (control n=7), group 2 (900 MHz EMF n=10) and group 3 (1800 MHz EMF n=9). Groups 2 and 3 were subjected to EMF for 20 days, daily between 13:00-17:00 pm for 4. Total protein (TP), albumin, globulin, plasma oxidant status (TOS), total antioxidant capacity (TAC) and Nitric Oxide (NO) levels were determined in plasma. Statistical comparision of data obtained from plasma analysis revealed a significant difference in guinea pigs subjected to 900 and 1800 MHz radioactive field for albumin, globulin and TOS levels (P<0.05). NO reflected a significant difference in 900 MHz EMF subjected guinea pigs, compared to the control group (P<0.05), however no differences were observed in 1800 MHz EMF subjected animals. Data obtained from ECG and plasma analysis indicated that EMF subjection may lead to some irregularities in the autonomic control of the heart in addition to oxidative damage.
The aim of this work was to study possible effects of environmental radiation pollution on plants. The association between cellular telephone (short duration, higher amplitude) and base station (long duration, very low amplitude) radiation exposure and the growth rate of soybean (Glycine max) seedlings was investigated. Soybean seedlings, pre-grown for 4 days, were exposed in a gigahertz transverse electromagnetic cell for 2 h to global system for mobile communication (GSM) mobile phone pulsed radiation or continuous wave (CW) radiation at 900 MHz with amplitudes of 5.7 and 41 V m−1, and outgrowth was studied one week after exposure. The exposure to higher amplitude (41 V m−1) GSM radiation resulted in diminished outgrowth of the epicotyl. The exposure to lower amplitude (5.7 V m−1) GSM radiation did not influence outgrowth of epicotyl, hypocotyls, or roots. The exposure to higher amplitude CW radiation resulted in reduced outgrowth of the roots whereas lower CW exposure resulted in a reduced outgrowth of the hypocotyl. Soybean seedlings were also exposed for 5 days to an extremely low level of radiation (GSM 900 MHz, 0.56 V m−1) and outgrowth was studied 2 days later. Growth of epicotyl and hypocotyl was found to be reduced, whereas the outgrowth of roots was stimulated. Our findings indicate that the observed effects were significantly dependent on field strength as well as amplitude modulation of the applied field. Bioelectromagnetics. 2015;9999:1–9. © 2015 Wiley Periodicals, Inc.
Various biological effects of exposure to extremely low frequency electromagnetic fields (ELF-EMFs) have been documented so far, but very little work has been carried out on plants. In this research, two states of seeds (wet, dry) of Brassica napus L. (dicot) and Zea mays L (monocot) were exposed to pulsed EMFs (15 min on, 15 min off) by magnitude of 1 to 7 mT in steps of 2 mT and the highest intensity was 10 mT for 1 to 4 hours in steps of 1 h. Exposure to EMFs was performed by a locally designed EMF generator. Three replicates, with 30 seeds in each one were placed in germinator with 23 • C temperature after treatment. The number of germinated seeds was registered on the 2nd day after moisturizing in Brassica napus and 6th day after moisturizing in Zea mays. Developmental growth characteristics including: root and shoot length, fresh and dried biomass weight of 7 days seedlings were measured. Seedlings grown from dry pretreated seeds of Brassica napus showed the most significant increase in developmental growth at 10 mT and seedlings grown from wet treated seeds showed the most significant decrease in developmental growth at 10 mT comparing to control (p < 0.05) we ob-served an overall stimulating effects of EMFs in Zea mays with respect to developmental growth characteristics and the most significant increase observed at 10 mT (p < 0.05). All experimental data suggested Monocotyledons are more resistant than Dicotyledons against EMFs as abiotic stress.
The activities of non – specific acid phosphatase and alkaline phosphatase were examined during ripening in the fruit of plantain (Musa paradisiaca L. cv. False horn). This study was carried out in order to determine the activities of these phosphohydrolytic enzymes in supplying inorganic phosphate that is required for the maintenance of various cellular metabolism such as the conversion of starch to sugar and the associated rise in respiration that occur during ripening in plantain. Acid phosphatase activity in plantain was found to increase significantly (P < 0.001) in all the ripening stages by 1.7 to 8.2 fold (from 2.05 ± 0.43 to 16.77 ± 0.08 µmol/min/g fresh wt.). On the other hand, alkaline phosphatase activity decreased significantly (P < 0.001) from the hard green stage (unripe) to the yellow with green tips stage (ripe) by 1.2 to 9.1 fold (from 2.34 ± 0.05 to 0.26 ± 0.03 µmol/min/g fresh wt.) and subsequently increased, from the fully ripe stage to the yellow with large black patches stage (overripe) by 1.9 to 2.5 fold (from 0.49 ± 0.09 to 0.64 ± 0.01 µmol/min/g fresh wt.). The results suggest that acid phosphatase is the main non – specific phosphatase that is responsible for the production and supply of inorganic phosphate during ripening in plantain fruits.
The objective of the present study was to investigate the changes of germination, growth rate and absorbance efficiency of photosynthetic pigments of maize grains after exposed to microwaves (MW). Experiment was carried out by exposing maize plants to continuous microwaves energy at (935.2-960.2 MHz with intensities 0.07-0.15 mW/cm2). The test plants and the control plants were subjected to the same environment during four weeks. The hypothesis was that plants exposed to MW would be different from those plants not exposed. The present experiment showed that germinating grains, growth rate (g dry wt./week and cm2/week) of exposed maize seedling and absorbance efficiency (η) significantly increased compared to the control. Also, photosynthetic pigments, total soluble sugar and total carbohydrates were positively affected by MW exposure. Microwaves altered the anatomical features of maize leaves by increasing midrib vascular bundle length, wing and assimilating layer thickness. In all measured variables differences between the control and the microwave treatment plants occurred.
In order to study a possible application of cerium-based techniques in plant cells, ATPase and acid phosphatase activities
have been compared in two cell lines of Pisum sativum calli, one sensitive to NaCI and the other selected to be grown under salinity (85 mM NaCI). ATPase activity was unchanged
and localized in the plasma membrane of both cell lines. Acid phosphatase activity was significantly increased in the salt-selected
line and localized in the cell walls, Golgi complex, multivesicular bodies and vacuoles. These results indicated a possible
involvement of both activities in the maintenance of cell growth in the selected line under saline conditions.
Plants store carbon predominantly as starch, and the metabolism of this polysaccharide is of importance to all life. In the past ten years the processes of starch synthesis have been well studied, however only recently has the same amount of attention been directed towards starch degradation, which previously had been focussed almost exclusively on degradation in germinating cereal grains. Studies of the degradation of diurnal leaf starch have revealed a number of surprises, such as the importance of starch phosphorylation in initiating degradation, and shown that starch degradation in leaves differs significantly from that in cereal grains. We have previously shown that plants contain three distinct α-amylase families. T-DNA knockouts of each α-amylase family member in Arabidopsis had no effect on diurnal leaf starch degradation, raising questions about the function of α-amylases in leaves. Here we describe the known aspects of these three families and suggest specific roles for each in carbohydrate metabolism.
Accelerated and widespread use of different communication systems and modern electronic equipment increases exposure to radiofrequency electromagnetic fields (RF EMF) and raises serious concerns about the biological and health-related effects of RF radiation. Numerous studies document various biological effects of RF radiation. However, most of these findings derive from epidemiological, animal and in vitro studies while only a few investigate effects of RF radiation on plants.
The purpose of our study was to investigate the alterations in enzyme activities in leaves after exposure of plants Plectranthus sp. to 900 MHz EMF and their dependence on the time elapsed after exposure.
Plectranthus is the largest South African genus of plants belonging to the mint family (Lamiaceae). The ornamental herbaceous plant Plectranthus sp. was used as a model plant for investigating the effects of 900 MHz EMF. Plants were exposed whole body for 1 hour to EM radiation from GSM mobile phone (carrier frequency 902 MHz, 2 W pulse output power) at 20 cm distance from the antenna. Alterations in activity of isocitrate dehydrogenase, malate dehydrogenase and glucose-6-phosphate dehydrogenase in leaves were registered immediately after the end of the exposure and 1, 2 and 24 hours later. Irradiation of plants induced different alterations in enzyme activities depending on the time elapsed after irradiation. Immediately after exposure the activity of the three investigated enzymes decreased, but increased at 24th hour.
In conclusion, the data provide evidence that plants perceive and respond to electromagnetic fields and are a good model to study the effects of mobile phone radiation.
The effect of the exposure of maize seeds to stationary magnetic fields on germination and early growth has been studied under laboratory conditions. Seeds were magnetically exposed to one of two magnetic field strengths, 125 or 250 mT for different periods of time. Mean germination time and the time required to obtain 10, 25, 50, 75 and 90% of seeds to germinate were calculated. The results showed a reduction of these parameters for most of magnetic treatments, therefore their rate of germination was increased.Growth data measured on the 7th and 10th day after seeding allowed us to corroborate the effect observed in germination tests. Treated plants grew higher and heavier than control; on the 10th day total length was greater than control plants exposed to stationary magnetic field, corresponding with increase of the total fresh weight. The greatest increases were obtained for plants continuously exposed to 125 or 250 mT.
Objective
During the last decade, mobile phone use increased to almost 100% prevalence in many countries of the world. Evidence for potential health hazards accumulated in parallel by epidemiologic investigations has raised controversies about the appropriate interpretation and the degree of bias and confounding responsible for reduced or increased risk estimates.
Data Sources
Overall, I identified 33 epidemiologic studies in the peer-reviewed literature, most of which (25) were about brain tumors. Two groups have collected data for ≥ 10 years of mobile phone use: Hardell and colleagues from Sweden and the Interphone group, an international consortium from 13 countries coordinated by the International Agency for Research on Cancer.
Data Synthesis
Combined odds ratios (95% confidence intervals) from these studies for glioma, acoustic neuroma, and meningioma were 1.5 (1.2–1.8); 1.3 (0.95–1.9); and 1.1 (0.8–1.4), respectively.
Conclusions
Methodologic considerations revealed that three important conditions for epidemiologic studies to detect an increased risk are not met: a ) no evidence-based exposure metric is available; b) the observed duration of mobile phone use is generally still too low; c) no evidence-based selection of end points among the grossly different types of neoplasias is possible because of lack of etiologic hypotheses. Concerning risk estimates, selection bias, misclassification bias, and effects of the disease on mobile phone use could have reduced estimates, and recall bias may have led to spuriously increased risks. The overall evidence speaks in favor of an increased risk, but its magnitude cannot be assessed at present because of insufficient information on long-term use.
Invertase is an important enzyme used in many fields especially in food industry to produce fructose syrups. The current study focused on increasing invertase production by exposing Rhodotorula glutinis to extremely low magnetic fields (ELMF; 0 and 7 mT). For this purpose, the microorganism was allowed to grow in normal magnetic field and ELMF for 72 hours at the same temperature (24 ± 2°C). The fermentation was carried out in submerged culture for 120 hours. The results showed that invertase production is strongly dependent on the growth conditions of the microorganism. Both of the different magnetic fields applied to R. glutinis increased invertase production ranged from 48%-67% when compared with the control. On the other hand, ELMF treatment increased biomass formation about 14%-28% when compared with the control. As a result, magnetic field treatment could effectively be used in the production of invertase by R. glutinis.
Human populations are increasingly exposed to microwave/radiofrequency (RF) emissions from wireless communication technology, including mobile phones and their base stations. By searching PubMed, we identified a total of 10 epidemiological studies that assessed for putative health effects of mobile phone base stations. Seven of these studies explored the association between base station proximity and neurobehavioral effects and three investigated cancer. We found that eight of the 10 studies reported increased prevalence of adverse neurobehavioral symptoms or cancer in populations living at distances < 500 meters from base stations. None of the studies reported exposure above accepted international guidelines, suggesting that current guidelines may be inadequate in protecting the health of human populations. We believe that comprehensive epidemiological studies of long-term mobile phone base station exposure are urgently required to more definitively understand its health impact.
The indiscriminate use of wireless technologies, particularly of cell phones, has increased the health risks among living organisms including plants. We investigated the impact of cell phone electromagentic field (EMF) radiations (power density, 8.55 microW cm(-2)) on germination, early growth, proteins and carbohydrate contents, and activities of some enzymes in Vigna radiata. Cell phone EMF radiations significantly reduced the seedling length and dry weight of V radiata after exposure for 0.5, 1, 2, and 4 h. Furthermore, the contents of proteins and carbohydrates were reduced in EMF-exposed plants. However, the activities of proteases, alpha-amylases, beta-amylases, polyphenol oxidases, and peroxidases were enhanced in EMF-exposed radicles indicating their role in providing protection against EMF-induced stress. The study concludes that cell phone EMFs impair early growth of V radiata seedlings by inducing biochemical changes.
Evidence suggests that cell processes can be influenced by weak electromagnetic fields (EMFs). EMFs appear to represent a global interference or stress to which a cell can adapt without catastrophic consequences. There may be exceptions to this observation, however, such as the putative role of EMFs as promoters in the presence of a primary tumor initiator. The nature of the response suggests that the cell is viewing EMFs as it would another subtle environmental change. The age and state of the cell can profoundly affect the EMF bioresponse. There is no evidence that direct posttranscription effects occur as a result of EMF exposure. Although transcription alterations occur, no apparent disruption in routine physiological processes such as growth and division is immediately evident. What is usually observed is a transient perturbation followed by an adjustment by the normal homeostatic machinery of the cells. DNA does not appear to be significantly altered by EMF. If EMF exposure is associated with an increased risk of cancer, the paucity of genotoxic effects would support the suggestion that the fields act in tumor promotion rather than initiation. The site(s) and mechanisms of interaction remain to be elaborated. Although there are numerous studies and hypotheses that suggest the membrane represents the primary site of interaction, there are also several different studies showing that in vitro systems, including cell-free systems, are responsive to EMFs. The debate about potential hazards or therapeutic value of weak electromagnetic fields will continue until the mechanism of interaction has been clarified.
A previously unknown maltose transporter is essential for the conversion of starch to sucrose in Arabidopsis leaves at night. The transporter was identified by isolating two allelic mutants with high starch levels and very high maltose,
an intermediate of starch breakdown. The mutations affect a gene of previously unknown function, MEX1. We show that MEX1is a maltose transporter that is unrelated to other sugar transporters. The severe mex1 phenotype demonstrates that MEX1is the predominant route of carbohydrate export from chloroplasts at night. Homologous genes
in plants including rice and potato indicate that maltose export is of widespread significance.
A number of studies have demonstrated beta-amylase induction in response to abiotic stress. In the present work, a temperature response profile in 5 degrees C increments from 45 degrees C to 0 degrees C showed that induction at temperature extremes was specific for two members of the gene family (BMY7 and BMY8). Both members encode proteins that possess apparent transit peptides for chloroplast stromal localization. However, induction was not observed for other key starch degrading enzymes demonstrating a rather specific response to temperature stress for BMY7 and BMY8. Time course experiments for heat shock at 40 degrees C and cold shock at 5 degrees C showed that beta-amylase induction correlated with maltose accumulation. Maltose has the ability, as demonstrated by in vitro assays, to protect proteins, membranes, and the photosynthetic electron transport chain at physiologically relevant concentrations. Therefore, beta-amylase induction and the resultant maltose accumulation may function as a compatible-solute stabilizing factor in the chloroplast stroma in response to acute temperature stress.
Throughout the evolution process, Earth's magnetic field (MF, about 50 microT) was a natural component of the environment for living organisms. Biological objects, flying on planned long-term interplanetary missions, would experience much weaker magnetic fields, since galactic MF is known to be 0.1-1 nT. However, the role of weak magnetic fields and their influence on functioning of biological organisms are still insufficiently understood, and is actively studied. Numerous experiments with seedlings of different plant species placed in weak magnetic field have shown that the growth of their primary roots is inhibited during early germination stages in comparison with control. The proliferative activity and cell reproduction in meristem of plant roots are reduced in weak magnetic field. Cell reproductive cycle slows down due to the expansion of G1 phase in many plant species (and of G2 phase in flax and lentil roots), while other phases of cell cycle remain relatively stable. In plant cells exposed to weak magnetic field, the functional activity of genome at early pre-replicate period is shown to decrease. Weak magnetic field causes intensification of protein synthesis and disintegration in plant roots. At ultrastructural level, changes in distribution of condensed chromatin and nucleolus compactization in nuclei, noticeable accumulation of lipid bodies, development of a lytic compartment (vacuoles, cytosegresomes and paramural bodies), and reduction of phytoferritin in plastids in meristem cells were observed in pea roots exposed to weak magnetic field. Mitochondria were found to be very sensitive to weak magnetic field: their size and relative volume in cells increase, matrix becomes electron-transparent, and cristae reduce. Cytochemical studies indicate that cells of plant roots exposed to weak magnetic field show Ca2+ over-saturation in all organelles and in cytoplasm unlike the control ones. The data presented suggest that prolonged exposures of plants to weak magnetic field may cause different biological effects at the cellular, tissue and organ levels. They may be functionally related to systems that regulate plant metabolism including the intracellular Ca2+ homeostasis. However, our understanding of very complex fundamental mechanisms and sites of interactions between weak magnetic fields and biological systems is still incomplete and still deserve strong research efforts.
Using an especially-designed facility, the Mode Stirred Reverberation Chamber, we exposed tomato plants (Lycopersicon esculentum Mill. VFN8) to low level (900 MHz, 5 V m(-1)) electromagnetic fields for a short period (10 min) and measured changes in abundance of three specific mRNA soon after exposure. Within minutes of electromagnetic stimulation, stress-related mRNA (calmodulin, calcium-dependent protein kinase and proteinase inhibitor) accumulated in a rapid, large and 3-phase manner typical of an environmental stress response. Accumulation of these transcripts into the polysomal RNA also took place (indicating that the encoded proteins were translated) but was delayed (indicating that newly-synthesized mRNA was not immediately recruited into polysomes). Transcript accumulation was maximal at normal Ca(2+) levels and was depressed at higher Ca(2+), especially for those encoding calcium-binding proteins. Removal of Ca(2+) (by addition of chelating agents or Ca(2+) channel blocker) led to total suppression of mRNA accumulation. Finally, 30 min after the electromagnetic treatment, ATP concentration and adenylate energy charge were transiently decreased, while transcript accumulation was totally prevented by application of the uncoupling reagent, CCCP. These responses occur very soon after exposure, strongly suggesting that they are the direct consequence of application of radio-frequency fields and their similarities to wound responses strongly suggests that this radiation is perceived by plants as an injurious stimulus.
Two exposure systems of an extremely low frequency electric field were used in this work. The first was an experimental model (50 Hz – 6 KV/m strength) and the second was the high voltage transmission lines passing through an open agricultural field (50 Hz – 66 KV/11m). The effect of the two exposure systems was investigated on mitosis, meiosis and pollen grains viability in the wheat plant to reflect the different abnormalities in the chromosome behaviour. The effect of the two fields on some morphological characters such as the stem length, the spike number, spike weight per plant and the number of grains per spike together with some physiological parameters such as the chlorophyll content. the element levels, carbohydrate content, and total crude protein were estimated for exposed and unexposed grains. Classification of the water soluble protein (WSP) extracted from the exposed and unexposed grains as well as their molecular weight distribution were investigated by using SDS polyacrelimide gel electrophoresis technique. The absorption spectra of the WSP also measured at wavelength range 200-600nm. The results indicated that the electric field caused a marked effect on the frequency of different mitotic phases. Both of the two exposure systems showed a decrease in the mitotic index of wheat root meristematic cells with induction of high frequency of chromosomal abnormalities. In the other hand the treated wheat flower buds showed an increase in the percentage of abnormal pollen mother cells (PMCs) and a marked increase in the frequency of the nonviable pollen grains. The results also indicated remarkable changes in the morphological characters of the exposed grains where the stem length increased but the spike weight and the number of grains in the spike decreased. Further, the data showed an increase in the total chlorophyll content and the total carbohydrates in the grains. Furthermore, the amount of total protein in the exposed grains decreased. A pronounced change occurred in the concentration of the elements due to the exposure processes. On the other hand, the data indicated that the molecular structure of the extracted WSP changed the amount of protein in the bands of exposed grains decreased and their molecular weight changed and also fluctuation in the electrophoretic mobility of the protein bands.
The present study examined the toxic effects of Cr(VI; 100, 250 and 500 μM) in maize seedlings by investigating the changes in carbohydrate metabolism after 48, 96, and 144 h of exposure. Cr-stress results in severe alterations in the contents of carbohydrates and reducing sugars and the activities of carbohydrate metabolizing enzymes, amylases, phosphatases and phosphorylases, and invertases in maize seedlings. Under Cr stress, the contents of carbohydrates and reducing sugars declined in roots, whereas an increase was noticed in leaves. The catalytic activity of carbohydrate metabolizing enzymes, except invertases, in roots declined in the presence of Cr(VI) in a concentration- and exposure time-dependent manner. In contrast, the activities of these enzymes were enhanced in leaves under Cr(VI) stress. The activity of invertases increased with increasing amount of Cr(VI) but declined with an increase in the time interval. In conclusion, our results show that carbohydrate metabolism is severely affected under Cr(VI) toxicity. The study suggests that Cr-induced perturbations in the carbohydrate metabolism are one of the factors resulting in growth inhibition under Cr(VI) stress.
We investigated the influence of a magnetic field on photosynthesis in, and the growth of Spirulina platensis (S. platensis), under magnetic fields with magnetic flux densities varying from 0.5 gauss (geomagnetic field) to 700 gauss. The specific growth rate of S. platensis was the highest at 100 gauss, being 1.5-fold that at 0.5 gauss, while the growth was obviously inhibited at 700 gauss. The existence of a magnetic field had no effect on the growth when S. platensis was cultured in the dark on a medium containing 0.3% glucose. The oxygen evolution rate during photosynthesis increased with increase in magnetic flux density, and the intracellular concentrations of sugar and phycocyanin, a light-harvesting pigment present in the thylakoid membrane in which reactions of the photosynthetic electron transfer system occur, reached maximal values at 100 gauss. At magnetic flux densities of a over 100 gauss, the phycocyanin content decreased with increase in magnetic flux density. The content of glyceroglycolipid, which exists exclusively in the thylakoid membrane, decreased with increase in magnetic flux density, especially so at 700 gauss, when it became 44% that at 0.5 gauss. From the aforementioned results, it is evident that magnetic fields accelerate the growth of S. platensis associated with activation of light excitation in the photosynthetic electron transfer system and increase in phycocyanin contents, and that these effects are maximal at magnetic flux densities of around 100 gauss. Nevertheless, when a magnetic flux density of over 400 gauss was applied, growth inhibition was observed with decrease in the phycocyanin content, and production of chemical energy necessary for sugar synthesis.
A simple, rapid method requiring few manipulations for the extraction of chlorophylls from fragmented leaf tissue of angiosperms and gymnosperms is compared with the widely used acetone method. Unlike the acetone method where grinding and subsequent centrifugation are essential, this method makes use of incubation at 65 °C of leaf tissue immersed in dimethyl sulphoxide. The new method was found to be as efficient as acetone for chlorophyll extraction and superior in terms of chlorophyll stability.
The aim of this study is to investigate the effect of low-intensity static magnetic fields (SMFs) on invertase activity and growth on different newly identified molds. The most positive effect of SMFs on invertase activity and growth was observed for Aspergillus niger OZ-3. The submerged production of invertase was performed with the spores obtained at the different exposure times (120, 144, 168, and 196 hr) and magnetic field intensities (0.45, 3, 5, 7, and 9 mT). The normal magnetic field of the laboratory was assayed as 0.45 mT (control). Optimization of magnetic field intensity and exposure time significantly increased biomass production and invertase activity compared to 0.45 mT. The maximum invertase activity (51.14 U/mL) and biomass concentration (4.36 g/L) were achieved with the spores obtained at the 144 hr exposure time and 5 mT magnetic field intensity. The effect of low-intensity static magnetic fields (SMFs) on invertase activities of molds was investigated for the first time in the present study. As an additional contribution, a new hyper-invertase-producing mold strain was isolated. Supplemental materials are available for this article. Go to the publisher's online edition of Preparative Biochemistry and Biotechnology to view the supplemental file.
Hydrolysis of phosphate esters is a critical process in the energy metabolism and metabolic regulation of plant cells. This review summarizes the characteristics and putative roles of plant acid phosphatase (APase). Although immunologically closely related, plant APases display remarkable heterogeneity with regards to their kinetic and molecular properties, and subcellular location. The secreted APases of roots and cell cultures are relatively non-specific enzymes that appear to be important in the hydrolysis and mobilization of Pi from extracellular phosphomonoesters for plant nutrition. Intracellular APases are undoubtedly involved in the routine utilization of Pi reserves or other Pi-containing compounds. A special class of intracellular APase exists that demonstrate a clear-cut (but generally nonabsolute) substrate selectivity. These APases are hypothesized to have distinct metabolic functions and include: phytase, phosphoglycolate phosphatase, 3-phosphoglycerate phosphatase, phosphoenolpyruvate phosphatase, and phosphotyrosyl-protein phosphatase. APase expression is regulated by a variety of developmental and environmental factors. Pi starvation induces de novo synthesis of extra- and intracellular APases in cell cultures as well as in whole plants. Recommendations are made to achieve uniformity in the analyses of the different APase isoforms normally encountered within and between different plant tissues.
The pod mesophyll of field beans accumulates large amounts of starch during stage 1 of embryogenesis, which is later utilized during stage 2. The activity of starch degradation in the pod is under metabolic control of the enclosed seeds. Changes in the isoenzyme pattern of α-amylase and not starch phosphorylase coincide with the beginning of the starch degradation period in the pods. Mesophyll cells of the pods contain the same α-amylase isoenzymes as the endocarp but exhibit a higher α-amylase activity that parallels the much higher starch content of this tissue in comparison to the endocarp. Regulation of starch breakdown may be mediated at least in part by the formation of a special α-amylase isoenzyme.
We studied the response of root growth to different magnetic fields and forces. We submitted the seeds of three plant species, Lens culinaris L., Glycine soja Siebold & Zucc., and Triticum aestivum L., which differ in concentrations of paramagnetic (e.g., Fe or Co) and diamagnetic materials (e.g., starchy amyloplasts), to different static magnetic fields and forces. A magnetic field of 176 G reduced root growth of L. culinaris, G. soja, and T. aestivum, 37, 31, and 15%, respectively. A weaker magnetic field of 21 G reduced root growth of L. culinaris and G. soja only 13 and 21%, respectively, whereas it had no significant effect on the cereal T. aestivum. The germinating seeds of L. culinaris and G. soja were less diamagnetic than T. aestivum, and the latter had a smaller paramagnetic component. Since at room temperature, the paramagnetic
The activities of soluble invertase (EC 3.2.1.26), cell wall invertase (EC 3.2.1.26) and sucrose synthase (EC 2.4.1.13) were determined in Easter lily (Lilium longiflorum Thunb. cv. Nellie White) floral organs during flower development. These enzyme activities were correlated with dry weight gains and carbohydrate pools to investigate the importance of their expression in maintaining sink strength of floral organs. In the early stages of flower bud development, anthers exhibited the highest rates of dry weight gain and activity of sucrolytic enzymes. Once anther growth was completed, the dry weight gain of tepal, filament, stigma and style increased with a concomitant increase in hexose concentrations and invertase activity. Although all three enzymes capable of catalyzing sucrose cleavage were present in every flower organ of L. longiflorum, soluble invertase was the predominant enzyme in all flower organs except stigma where cell wall invertase dominated. Soluble invertase activity was highly correlated with dry weight gain in most of the flower organs.
During the last couple of decades, there has been a tremendous increase in the use of cell phones. It has significantly added to the rapidly increasing EMF smog, an unprecedented type of pollution consisting of radiation in the environment, thereby prompting the scientists to study the effects on humans. However, not many studies have been conducted to explore the effects of cell phone EMFr on growth and biochemical changes in plants. We investigated whether EMFr from cell phones inhibit growth of Vigna radiata (mung bean) through induction of conventional stress responses. Effects of cell phone EMFr (power density: 8.55 µW cm− 2; 900 MHz band width; for ½, 1, 2, and 4 h) were determined by measuring the generation of reactive oxygen species (ROS) in terms of malondialdehyde and hydrogen peroxide (H2O2) content, root oxidizability and changes in levels of antioxidant enzymes. Our results showed that cell phone EMFr significantly inhibited the germination (at ≥2 h), and radicle and plumule growths (≥1 h) in mung bean in a time-dependent manner. Further, cell phone EMFr enhanced MDA content (indicating lipid peroxidation), and increased H2O2 accumulation and root oxidizability in mung bean roots, thereby inducing oxidative stress and cellular damage. In response to EMFr, there was a significant upregulation in the activities of scavenging enzymes, such as superoxide dismutases, ascorbate peroxidases, guaiacol peroxidases, catalases and glutathione reductases, in mung bean roots. The study concluded that cell phone EMFr inhibit root growth of mung bean by inducing ROS-generated oxidative stress despite increased activities of antioxidant enzymes.
Anyone reading this book cannot fail to realize the importance of self-generated electric fields and currents in the energetics and control of metabolism in plants. We should therefore not be too surprised to find that externally applied fields also have effects. In this chapter, I will describe a few of the more significant findings from over a century of research and try to explain and sometimes reinterpret them in the light of more modern knowledge. The work is divided into three sections. Section 1 is on the non-polar effects of DC fields, where the effects are not related to the direction of the field. It ranges from responses to massive electric fields, such as those found in thunderstorms, to the effects of much weaker ones on the growth and differentiation of tissue cultures. Section 2 is on the polar effects of DC fields, where the direction of the response is related to the direction of the field and includes effects on polar growth and tropisms. Section 3 is on the effects of time-varying and alternating electromagnetic fields, where I will present evidence that a simple change in membrane stability can account for virtually all of the hitherto mysterious biological effects of weak electromagnetic radiation.
Indiscriminate adoption and use of cell phone technology has tremendously increased the levels of electromagnetic field radiations (EMFr) in the natural environment. It has raised the concerns among the scientists regarding the possible risks of EMFr to living organisms. However, not much has been done to assess the damage caused to plants that are continuously exposed to EMFr present in the environment. The present study investigated the biochemical mechanism of interference of 900 MHz cell phone EMFr with root formation in mung bean (Vigna radiata syn. Phaseolus aureus) hypocotyls, a model system to study rhizogenesis in plants. Cell phone EMFr enhanced the activities of proteases (by 1.52 to 2.33 times), polyphenol oxidases (by 1.5 to 4.3 times), and peroxidases (by 1.5 to 2.0 times) in mung bean hypocotyls over control. Further, EMFr enhanced malondialdehyde (an indicator of lipid peroxidation), hydrogen peroxide, and proline content, indicating a reactive oxygen species-mediated oxidative damage in hypocotyls. It was confirmed by the upregulation in the activities of antioxidant enzymes (superoxide dismutase, ascorbate peroxidase, guaiacol peroxidase, catalase, and glutathione reductase) suggesting their possible role in providing protection against EMFr-induced oxidative damage. The study concluded that cell phone radiations affect the process of rhizogenesis through biochemical alterations that manifest as oxidative damage resulting in root impairment.
The effects of exposure to radiofrequency electromagnetic fields (RF-EMFs) on seed germination, primary root growth as well as mitotic activity and mitotic aberrations in root meristematic cells were examined in Allium cepa L. cv. Srebrnjak Majski. Seeds were exposed for 2h to EMFs of 400 and 900MHz at field strengths of 10, 23, 41 and 120Vm(-1). The effect of longer exposure time (4h) and field modulation was investigated at 23Vm(-1) as well. Germination rate and root length did not change significantly after exposure to radiofrequency fields under any of the treatment conditions. At 900MHz, exposures to EMFs of higher field strengths (41 and 120Vm(-1)) or to modulated fields showed a significant increase of the mitotic index compared with corresponding controls, while the percentage of mitotic abnormalities increased after all exposure treatments. On the other hand, at 400MHz the mitotic index increased only after exposure to modulated EMF. At this frequency, compared with the control higher numbers of mitotic abnormalities were found after exposure to modulated EMF as well as after exposure to EMFs of higher strengths (41 and 120Vm(-1)). The types of aberration induced by the EMFs of both frequencies were quite similar, mainly consisting of lagging chromosomes, vagrants, disturbed anaphases and chromosome stickiness. Our results show that non-thermal exposure to the radiofrequency fields investigated here can induce mitotic aberrations in root meristematic cells of A. cepa. The observed effects were markedly dependent on the field frequencies applied as well as on field strength and modulation. Our findings also indicate that mitotic effects of RF-EMF could be due to impairment of the mitotic spindle.
A protein determination method which involves the binding of Coomassie Brilliant Blue G-250 to protein is described. The binding of the dye to protein causes a shift in the absorption maximum of the dye from 465 to 595 nm, and it is the increase in absorption at 595 nm which is monitored. This assay is very reproducible and rapid with the dye binding process virtually complete in approximately 2 min with good color stability for 1 hr. There is little or no interference from cations such as sodium or potassium nor from carbohydrates such as sucrose. A small amount of color is developed in the presence of strongly alkaline buffering agents, but the assay may be run accurately by the use of proper buffer controls. The only components found to give excessive interfering color in the assay are relatively large amounts of detergents such as sodium dodecyl sulfate, Triton X-100, and commercial glassware detergents. Interference by small amounts of detergent may be eliminated by the use of proper controls.
Sink organs of most plant species are supplied with carbon and energy in the form of sucrose. The channeling of sucrose into sink metabolism requires its cleavage by several isoforms of invertase and sucrose synthase, which are localized in different subcellular compartments. These activities regulate the entry of sucrose into distinct biochemical pathways, such as respiration or biosynthesis of cell wall polysaccharides and storage reserves. Other vital roles for the sucrose-cleaving enzymes include invertase activity at the site of phloem unloading and vacuolar invertase and sucrose synthase in sink organs, which drives the long-distance transport of sucrose. In addition, invertases have been implicated in the defense response and in turgor-driven cell expansion, and sucrose synthase expression is associated with low temperature and anaerobiosis responses. Finally, because sugars also regulate gene expression, the sucrose-cleaving enzymes play a fundamental role in controlling cell differentiation and development.
In our earlier experiments, we discovered that magnetic field exposure could bring both stabilizing and destabilizing effects to the DNA of Escherichia coli, depending on our parameters of assessment, and both of these effects were associated with the induced synthesis of the heat shock proteins Hsp70/Hsp40 (DnaK/DnaJ). These contradicting results prompted us to explore in this study the effect of magnetic field exposure on the DNA stability in vivo when the heat shock response of the cell was suppressed. By using plasmid pUC18 in E. coli as the indicator, we found that without the protection of the heat shock response, magnetic field exposure indeed induced DNA degradation and this deleterious effect could be diminished by the presence of an antioxidant, Trolox C. In our in vitro test, we also showed that the magnetic field could potentiate the activity of oxidant radicals.
Low temperature represents one of the principal limitations in species distribution and crop productivity. Responses to chilling include the accumulation of simple carbohydrates and changes in enzymes involved in their metabolism. Soluble carbohydrate levels and invertase, sucrose synthase (SS), sucrose-6-phosphate synthase (SPS) and alpha-amylase activities were analysed in cotyledons and embryonic axes of quinoa seedlings grown at 5 degrees C and 25 degrees C in the dark. Significant differences in enzyme activities and carbohydrate levels were observed. Sucrose content in cotyledons was found to be similar in both treatments, while in embryonic axes there were differences. Invertase activity was the most sensitive to temperature in both organs; however, SS and SPS activities appear to be less stress-sensitive. Results suggest that 1) metabolism in germinating perispermic seeds would be different from endospermic seeds, 2) sucrose futile cycles would be operating in cotyledons, but not in embryonic axes of quinoa seedlings under our experimental conditions, 3) low temperature might induce different regulatory mechanisms on invertase, SS and SPS enzymes in both cotyledons and embryonic axes of quinoa seedlings, and 4) low temperature rather than water uptake would be mainly responsible for the changes observed in carbohydrate and related enzyme activities.
The disaccharide sucrose and the cleavage products glucose and fructose are the central molecules for carbohydrate translocation, metabolism and sensing in higher plants. Invertases mediate the hydrolytic cleavage of sucrose into the hexose monomers. Plants possess three types of invertases, which are located in the apoplast, the cytoplasm and the vacuole, respectively. It has become evident that extracellular and vacuolar invertase isoenzymes are key metabolic enzymes that are involved in various aspects of the plant life cycle and the response of the plant to environmental stimuli because their substrates and reaction products are both nutrients and signal molecules. Invertases, alone or in combination with plant hormones, can regulate many aspects of the growth and development of plants from gene expression to long-distance nutrient allocation and are involved in regulating carbohydrate partitioning, developmental processes, hormone responses and biotic and abiotic interactions.
Chlorophylls were quantitatively studied in the leaves of black locust (Robinia pseudoacacia L.) seedlings exposed to electromagnetic fields of high frequency. Exposure system was designed and built up to make possible simultaneous exposure of seedling lots (3 months old) to low power density electromagnetic fields corresponding to a frequency of 400 MHz. After three weeks of daily exposures (1, 2, 3 and 8 hours), chlorophyll levels were measured using adequate spectral device. Statistical analysis of experimental results was performed by means of t-test to identify significant modifications induced by electromagnetic treatment in exposed samples in comparison to the control. Chlorophyll-a as well as chlorophyll-b level was found to decrease except the exposure time of two hours, where a considerable enhancement was noticed. It was revealed that the ratio of the two main types of chlorophyll was decreasing logarithmically to the increase of daily exposure time.
Widespread use of radiofrequency radiation emitting devices increased the exposure to electromagnetic fields (EMFs) from 300 MHz to 300 GHz. Various biological effects of exposure to these fields have been documented so far, but very little work has been carried out on plants. The aim of the present work was to investigate the physiological responses of the plant Lemna minor after exposure to radiofrequency EMFs, and in particular, to clarify the possible role of oxidative stress in the observed effects. Duckweed was exposed for 2 h to EMFs of 400 and 900 MHz at field strengths of 10, 23, 41 and 120 V m(-1). The effect of a longer exposure time (4 h) and modulation was also investigated. After exposure, parameters of oxidative stress, such as lipid peroxidation, H(2)O(2) content, activities and isoenzyme pattern of antioxidative enzymes as well as HSP70 expression were evaluated. At 400 MHz, lipid peroxidation and H(2)O(2) content were significantly enhanced in duckweed exposed to EMFs of 23 and 120 V m(-1) while other exposure treatments did not have an effect. Compared to the controls, the activities of antioxidative enzymes showed different behaviour: catalase (CAT) activity increased after most exposure treatments while pyrogallol (PPX) and ascorbate peroxidase (APX) activities were not changed. Exceptions were reduced PPX and APX activity after longer exposure at 23 V m(-1) and increased PPX activity after exposures at 10 and 120 V m(-1). By contrast, at 900 MHz almost all exposure treatments significantly increased level of lipid peroxidation and H(2)O(2) content but mostly decreased PPX activity and did not affect CAT activity. Exceptions were exposures to a modulated field and to the field of 120 V m(-1) which increased PPX and CAT activity. At this frequency APX activity was significantly decreased after exposure at 10 V m(-1) and longer exposure at 23 V m(-1) but it increased after a shorter exposure at 23 V m(-1). At both frequencies no differences in isoenzyme patterns of antioxidative enzymes or HSP70 level were found between control and exposed plants. Our results showed that non-thermal exposure to investigated radiofrequency fields induced oxidative stress in duckweed as well as unspecific stress responses, especially of antioxidative enzymes. However, the observed effects markedly depended on the field frequencies applied as well as on other exposure parameters (strength, modulation and exposure time). Enhanced lipid peroxidation and H(2)O(2) content accompanied by diminished antioxidative enzymes activity caused by exposure to investigated EMFs, especially at 900 MHz, indicate that oxidative stress could partly be due to changed activities of antioxidative enzymes.
A method for the extraction of chlorophyll from leaf tissue without maceration
- J D Hiscox
- G F Israelstem
- JD Hiscox
Hiscox JD, Israelstem GF (1979) A method for the extraction of chlorophyll from leaf tissue without maceration. Can J Bot 57:1332-1334