In this study, we aimed to develop a novel directional electromagnetic field (EMF) application method for promoting plant growth using a solenoid coil-based cultivation system. The emergence of plant shoots from seeds, shoot elongation, root proliferation, and plant growth hormones were monitored in the presence of a directional EMF using our solenoid coil system. To observe the effect of the directional EMF on seed germination, radish and sugarcane seedlings were cultivated in the system. At the seed germination stage, the EMF applied had no significant effect on germination or growth. However, after germination, shoot growth was sensitive to a directional EMF, as it was promoted by different conditions in a plant-species-dependent manner. The maximum growth promotion rates were 25.65% ± 4.21% and 38.57% ± 12.81% for radish and sugarcane, respectively. Similarly, plant root proliferation and indole-3-acetic acid (IAA) analyses indicated that directional EMF application was associated with root proliferation and hormone synthesis. Plant growth in the experimental system proved controllable; either growth stimulation or reduction were possible as the system operating conditions were made to vary. Our findings indicate that the application of a specific directional EMF could serve as an electrical plant stimulant (or electrical fertilizer).

Objectives : In this study, the absorption of heavy metals in the soil from smoking areas using indoor plants and electrical grounding was investigated to increase the utility of indoor plants for soil decontamination.Methods : Soil from plant pots in a smoking area was collected for the experimental plant pot preparations. Some of the prepared pots were connected to electrical ground via an electrode. Kidney beans (Phaseolus vulgaris) were seeded, and their growth were observed. After 30 days of the cultivation, TOC (Total Organic Carbon), and metagenomics profiles in the soil was analyzed. To estimate the behavior of the heavy metals in soil and plants, Cadmium concentrations in the samples were analyzed using ICP-MS (Inductively Coupled Plasma-Mass Spectrometry).Results and Discussion : The connection of the electrical ground to the plant pot induced the rapid growth of plant (48.2 ± 2.3% increase in stem growth), compare to the plant in the pot without the electrical ground. TOC analysis showed that the soil from the grounded pots showed the highest value, compared to the control soil (3.08 ± 1.22%), and the soil from the pot without ground connection (2.3 ± 0.1%). The ICP-MS analysis indicated that the plant body in the grounded pot had the highest cadmium concentration at 0.33 ± 0.018 μg/kg. Using the metagenomic analysis, biomineralization related bacterial species (Nocardioides sp., Streptomyces sp., Sphingomonas sp. etc.) were identified from the grounded soil sample. These results suggested that the indoor plant cultivation with the electrical ground connection as an electrical fertilizer enhances the cadmium absorption by plant, exudate secretion from the plant root, and bacterial flora change in the rhizosphere.Conclusion Cadmium in the soil from the smoking area was absorbed by indoor plant with the electrical ground. Therefore, the application of the electrical ground connection (earth) to the electrically insulated outdoor plant pots might enhance the plant growth rate and physiological activity. This application could be a novel soil decontamination method using plants.

Objectives:The purpose of this study was to investigate the effect of plants on smoking area and its environment. For this purpose, two different smoking areas (with and without plants) were selected, and the number of smokers and spitting behaviors were monitored. Soil and leaves samples of each smoking area were taken to analyze the concentration of cadmium and distribution of soil microorganisms. Through this investigation, the role of plants in smoking area for the cadmium and microorganisms was estimated. Methods:In the selected smoking areas, number of smokers and the number of spitting behaviors were monitored. Cadmium (Cd) concentrations of leaves, topsoil and rhizosphere obtained from the smoking areas were analyzed with inductively coupled plasma mass spectrometry (ICP-MS). The microorganisms in soil samples were analyzed using denaturing gradient gel electrophoresis (DGGE) and 16s rRNA amplicon sequencing based metagenomics.Results and Discussion:In the case of smoking area with plants, number of smokers and number of total spitting behaviors were 176.67 ± 7.85 and 918.67 ± 40.8 times per hour, respectively. In smoking area without plants, the 153.67 ± 5.44 (smokers) and (829.8 ± 29.36 (spitting behavior) per hour were observed. Among the collected samples from the smoking areas, the highest Cd values (347.117 ± 24.542 μg/kg) were found in leaves of smoking area. In the case of smoking area without plants, the top soil samples showed the highest Cd concentration (295.77 ± 16.64 μg/kg). The results indicate that Cd released from cigarette ash, saliva and smoke can be accumulated in plants and soil. The results suggested that the presence of plants in the smoking area protect the accumulation of Cd in surrounding environments (soil and atmosphere). The metagenomic analysis of the soil samples showed that smoking and spitting behavior also affected microbial system in the smoking areas. The results showed that the microorganisms in smoking area were closely related to the heavy metal removing activities. Conclusion:Results suggested that the cadmium distribution in the smoking areas was significantly affected by the presence of live plants. In addition, the presence of plants in the smoking area induced the difference species microorganisms. These results suggested that the presence of plants in smoking area can protect the spread of cadmium to the surrounding environment.

The ability of biochars derived from fallen (F-BC) and non-fallen (NF-BC) maple leaves to adsorb Cu²⁺ ions from aqueous solutions was examined. Biochars were produced at pyrolysis temperatures of 350, 550, and 750 °C. Higher pyrolysis temperatures resulted in enhanced specific surface areas and promoted CaCO₃ crystallization while limiting MgCO₃ formation. The Cu²⁺ adsorption capacity depended on the biochar type and pyrolysis conditions. Although the Cu²⁺ adsorption efficiency of NF-BCs decreased with increasing pyrolysis temperature, F-BC550 exhibited a higher Cu²⁺ adsorption capacity than F-BC750. Additionally, the Cu²⁺ adsorption performance of both NF-BC350 and F-BC550 improved with increasing solution pH. Cu²⁺ adsorption onto NF-BC350 and F-BC550 followed the two-compartment first-order (involving fast and slow adsorption compartments) and Langmuir (meaning homogeneous monolayer adsorption) models, respectively. The maximum Cu²⁺ adsorption capacity of F-BC550 (147.3 mg Cu/g BC) was 7.8-fold higher than that of NF-BC350 (18.8 mg Cu/g BC), as determined by isotherm studies. The enhanced adsorption performance of F-BC550 may be attributable to physical adsorption facilitated by increased surface area and multiple mechanisms, including cationic attraction via functional groups, ion exchange (Ca and Mg), and van der Waals interaction facilitated by increased surface area. These findings suggest that F-BC550, derived from waste biomass, exhibits superior Cu²⁺ adsorption performance compared to NF-BCs, making it a promising adsorbent for wastewater treatment applications.

A method for particulate matter and airborne microorganisms removals using indoor plants with electrical ground connection was investigated. The electrochemically activated plants through electrical grounding were used as the basis of air purification system. In this study, a novel concept of plants-based indoor air purification system was examined in the presence of electrical ground connection. Epipremnum aureum was selected as a primary experimental plant. The cultivation pots with an electrode were connected to earth point via a wire. Experiments were conducted in a system where the pots were placed, with various concentrations of particulate matter and airborne microorganisms were applied to analyze removal rates. In addition, the effects of airflow speed and light conditions on the removal rates were also analyzed. The results demonstrated that applying electrical grounding to indoor plants significantly improved the particulate matter and airborne microorganisms removal rates. In the case of particulate matter removal, the grounded systems showed 75.7 ± 5.5% removal rate under air flow rate of 1.0m/s. Additionally, long-term experiments demonstrated that the grounded system maintained a stable particulate matter removal efficiency of over 60% for 35 days. Regarding airborne microorganisms removal, the grounded system achieved a removal efficiency of 63.3% ± 0.8% for airborne bacteria and 67.6% ± 1.6% for airborne fungi. This study confirmed that applying electrical grounding to indoor plants can significantly enhance their air purification performance. These results suggest that a simple grounding technique applied to potted plants can be an eco-friendly and effective solution for improving indoor air quality.

Precise nondestructive methods for monitoring soil water content (SWC) are essential for maintaining plant growth and metabolic activity. In this study, an inductance‐based monitoring system was developed using a solenoid‐coil sensor for continuous in situ SWC measurements. Three plant species, Melissa officinalis L., Ficus benghalensis L., and Podocarpus macrophyllus (Thunb.) Sweet, were selected as the experimental plants based on their distinct leaf morphologies and stomatal traits. In the control experiments, the inductance variation showed a strong linear correlation with soil moisture meter‐based SWC ( r ² = 0.900, p < 0.001). When the system was applied to live experimental plants, plant species‐specific differences in water consumption rates were monitored. The system showed a strong relationship between photosynthetic efficiency (Fv/Fm) and the inductance‐based SWC. These results indicate that the inductance measurement system supports rapid, reliable, and noninvasive plant cultivation based on an accurate watering schedule and enhanced water‐use efficiency.