Weak extremely high frequency microwaves affect pollen-tube emergence and growth in kiwifruit: pollen grain irradiation and water-mediated effects

Morphophysiological and Proteomic Responses on Plants of Irradiation with Electromagnetic Waves

Electromagnetic energy is the backbone of wireless communication systems, and its progressive use has resulted in impacts on a wide range of biological systems. The consequences of electromagnetic energy absorption on plants are insufficiently addressed. In the agricultural area, electromagnetic-wave irradiation has been used to develop crop varieties, manage insect pests, monitor fertilizer efficiency, and preserve agricultural produce. According to different frequencies and wavelengths, electromagnetic waves are typically divided into eight spectral bands, including audio waves, radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, and gamma rays. In this review, among these electromagnetic waves, effects of millimeter waves, ultraviolet, and gamma rays on plants are outlined, and their response mechanisms in plants through proteomic approaches are summarized. Furthermore, remarkable advancements of irradiating plants with electromagnetic waves, especially ultraviolet, are addressed, which shed light on future research in the electromagnetic field.

Proteomic and Biological Analyses Reveal the Effect on Growth under Flooding Stress of Chickpea Irradiated with Millimeter Waves

Chickpea cultivated on marginal lands in arid and semiarid tropics is one of the food legumes, and its growth is reduced by flooding stress. Millimeter-wave irradiation has influences on organisms, and it improves the growth of plants such as soybean. To reveal the dynamic effects of millimeter-wave irradiation on chickpea under flooding, gel- and label-free proteomic analysis was conducted. Millimeter-wave irradiation improved chickpea growth and its tolerance to flooding stress. According to functional categorization, oppositely changed proteins were correlated with photosynthesis, fermentation, and protein degradation. Immunoblot analysis confirmed that RuBisCO activase and large subunits decreased in leaves under flooding; however, they are recovered in irradiated chickpea even if it was in this condition. The activity and accumulation of alcohol dehydrogenase increased in roots under flooding; however, this followed the same pattern. Cell death was significantly increased and decreased by flooding on unirradiated and irradiated chickpeas, respectively. These findings suggest that irradiation with millimeter waves on chickpea seeds improves the recovery of plant growth through regulation of photosynthesis in leaves and fermentation in roots. Furthermore, millimeter-wave irradiation might promote chickpea tolerance under flooding via the regulation of cell death.

Proteomic Analysis of Irradiation with Millimeter Waves on Soybean Growth under Flooding Conditions

Improving soybean growth and tolerance under environmental stress is crucial for sustainable development. Millimeter waves are a radio-frequency band with a wavelength range of 1-10 mm that has dynamic effects on organisms. To investigate the potential effects of millimeter-waves irradiation on soybean seedlings, morphological and proteomic analyses were performed. Millimeter-waves irradiation improved the growth of roots/hypocotyl and the tolerance of soybean to flooding stress. Proteomic analysis indicated that the irradiated soybean seedlings recovered under oxidative stress during growth, whereas proteins related to glycolysis and ascorbate/glutathione metabolism were not affected. Immunoblot analysis confirmed the promotive effect of millimeter waves to glycolysis- and redox-related pathways under flooding conditions. Sugar metabolism was suppressed under flooding in unirradiated soybean seedlings, whereas it was activated in the irradiated ones, especially trehalose synthesis. These results suggest that millimeter-waves irradiation on soybean seeds promotes the recovery of soybean seedlings under oxidative stress, which positively regulates soybean growth through the regulation of glycolysis and redox related pathways.

In Vitro Pollen Tube Growth Reveals the Cytotoxic Potential of the Flavonols, Quercetin and Rutin

Flavonols are phytochemicals widely found in commonly consumed foods. In spite of their beneficial effects on human health, however, cytotoxicity and even suspected genotoxicity have also been reported for the flavonol, quercetin. This points to the need for preventive studies to identify any cytotoxic effects associated with pure flavonol intake. This work was performed with the aim of verifying whether a plant-based in vitro system, the pollen tube, could be used to evaluate the cytotoxic potential of exogenous flavonols. Increasing concentrations of the aglycone, quercetin, and its glycoside, rutin, were assayed with regard to tube growth of kiwifruit pollen, determined by applying the pollen tube growth test protocol. This test, based on the photometric quantification of pollen tube mass production in suspension cultures, has already been applied in the sensitive and reliable toxicological evaluation of a wide range of chemicals. Whereas 60-800 microM rutin promoted kiwifruit pollen tube elongation, 10-50 microM quercetin strongly inhibited growth, and also produced irreversible malformations, such as screw-like tube growth, abnormal vacuolation, alteration of organelle streaming, and nuclear positioning. Thus, the cytotoxic potentials of the two flavonols have been confirmed to differ. Pollen tubes seem to afford a promising test system for a preventive, rapid in vitro biosafety assessment of antioxidant nutritional supplements, without using laboratory animals.

Biophysical approach to low back pain: a pilot report

Since biophysical treatment has been reported to be effective in the general management of pain, we decided to assess the specific effect and treatment duration of this therapeutic strategy in low back pain. We were interested in verifying the possibility that a single clinical procedure could reduce pain and improve patients' quality of life within a period of three months. An Electromagnetic Information Transfer Through Aqueous System was employed to record endogenous therapeutic signals from each individual using an electromagnetic recording device (Med Select 729). A highly significant reduction in the Roland Morris low back pain and disability questionnaire score was observed after 3 months following a single biophysical intervention (11.83 ± 6 at baseline versus 2.3 ± 3.25 at 3 months, p < 0.0001). This preliminary report provides further evidence of the theoretical implications and clinical applications of Quantum Electro Dynamic concepts in biology and medicine.

Polyamine biosynthesis and control of the development of functional pollen in kiwifruit

The role of polyamines (PAs) in plant reproduction, especially pollen development and germination has been demonstrated in several higher plants. The aim of the present research was to investigate PA involvement in pollen development and germination in dioecious kiwifruit (Actinidia deliciosa). Differences in PA content, level and gene expression for PA biosynthetic enzymes, and the effect of PA biosynthetic inhibitors were found during pollen development (or abortion in female flowers). Whereas PAs, especially spermidine (Spd), remained high throughout the development of functional pollen, the levels collapsed by the last stage of development of sterile pollen. Mature and functional pollen from male-fertile anthers showed S-adenosyl methionine decarboxylase activity (SAMDC; involved in Spd biosynthesis) throughout microgametogenesis, with high levels of soluble SAMDC found starting from the late uninucleate microspore stage. Soluble SAMDC was absent in male-sterile anthers. Arginine decarboxylase [ADC; for putrescine (Put) biosynthesis] showed little difference in functional vs sterile pollen; ornithine decarboxylase [ODC; also for putrescine (Put) biosynthesis] was present only in sterile pollen. Ultrastructural studies of aborted pollen grains in male-sterile flowers showed that cytoplasmic residues near the intine contain vesicles, extruding towards the pollen wall. Very high SAMDC activity was found in the wall residues of the aborted pollen. The combined application in planta of competitive inhibitors of S-adenosylmethionine decarboxylase (MGBG) and of spermidine synthase (CHA), or of D-arginine (inhibitor of Put synthesis), to male-fertile plants led to abnormal pollen grains with reduced viability. The importance of PAs during male-fertile pollen germination was also found. In fact, PA biosynthetic enzymes (ADC and, mainly, SAMDC) were active early during pollen hydration and germination in vitro. Two different SAMDC gene transcripts were expressed in germinating pollen together with a lower level of ADC transcript. Gene expression preceded PA enzyme activity. The application of PA inhibitors in planta drastically reduced pollen germination. Thus, low free Spd can lead either to degeneration or loss of functionality of kiwifruit pollen grains.

Both trivalent and hexavalent chromium strongly alter in vitro germination and ultrastructure of kiwifruit pollen

Due to its widespread industrial use, chromium is considered a dangerous environmental pollutant. It is known to inhibit plant growth and development. The present study provides the first evidence of the toxicity of this metal on the male haploid generation of a higher plant. Both Cr(III) and Cr(VI) species, supplied as CrCl(3) and CrO(3), respectively, exerted a strong dose-dependent inhibitory effect on kiwifruit pollen tube emergence and growth. Cr(III) resulted more effective than Cr(VI) in the 16-75microM interval; moreover, complete inhibition of germination was attained at much lower doses than Cr(VI). Also tube morphology was affected. While the plasma membrane was still undamaged in the large majority of the treated pollen grains, dramatic ultrastructural alterations were induced by chromium including chromatin condensation, swelling of mitochondria, cytoplasmic vacuolization, and perturbed arrangement of endoplasmic reticulum cisternae. Thus, it seems that the impact of the two chromium species on kiwifruit pollen may result in severe compromission of both essential structures and functions of the male gametophyte.

Nonthermal microwave radiations affect the hypersensitive response of tobacco to tobacco mosaic virus

OBJECTIVES

The aim of the present study was to evaluate the effects of nonthermal extremely high-frequency microwave radiations in a plant-based bioassay, represented by tobacco plants reacting to tobacco mosaic virus with a hypersensitive response leading to the appearance of necrotic lesions at the infection sites.

DESIGN

This study was performed blind and different experimental protocols on tobacco plants inoculated with tobacco mosaic virus were used. BIO-OBJECTS: Tobacco plants (Nicotiana tabacum L. cultivar Samsun) carrying the resistance gene N against tobacco mosaic virus.

INTERVENTIONS

Tobacco plants or leaf disks were either directly or indirectly (water-mediated) irradiated using a medical device, designed for microwave resonance therapy. It produces nonthermal weak-intensity extremely high-frequency radiations, either modulated at extremely low frequency or in continuous flux of waves, coupled with a nonthermal red/near-infrared radiation.

OUTCOME MEASUREMENTS

The working variable was the number of hypersensitive lesions per leaf disk.

RESULTS

Both direct and indirect nonthermal microwave radiations led to significant effects on the hypersensitive response of tobacco plants: modulated radiations generally induced a resistance increase, whereas a continuous flux of waves induced a resistance decrease with direct treatments only.

CONCLUSIONS

Nonthermal microwave radiations are effective on the hypersensitive response of tobacco to tobacco mosaic virus and their low-frequency modulation seems to be more bioactive than the continuous-flux of waves, particularly in the indirect water-mediated treatments.