Atmospheric-pressure cold plasma assisted enhancement of germination and nutritional trait of peanut seeds

1 Introduction

In recent years, rapid population growth, environmental degradation, climate change, and urbanization have significantly increased the global demand for food. The Food and Agriculture Organization (FAO) estimates that the global population will reach 10 billion by 2050 [1]. To meet this growing demand, it is imperative to enhance both the quantity and quality of food production, even as we explore potential increases in food supply. Traditional methods for improving seed germination, such as exposing seeds to magnetic fields, ultraviolet light, and other physical treatments, have been widely used [2–4]. However, these conventional approaches often come with limitations, including being time-consuming and potentially harmful to the environment [5]. Therefore, there is a pressing need to develop innovative techniques that can enhance seed germination as well as plant growth more efficiently and sustainably.

One promising alternative to address the above-mentioned issues is the use of atmospheric pressure cold plasma (ACP) in agriculture. ACP is an efficient, innovative, and environmentally friendly technology that can rapidly induce seed germination without negative side effects [6,7]. In recent times, the research community demonstrated that ACP can accelerate seed germination, improve seed permeability and surface hydrophilicity, enhance plant growth, increase root branching and boost gene expression [8,9]. Dielectric barrier discharge (DBD) is a form of ACP that generates high-energy electrons, ultraviolet light, and active ions in the atmosphere. Therefore, DBD can be used to generate plasma for seed activation, either by direct discharge on the seed surface or indirectly by activating water, which irradiates the seed surface [10]. The discharge in air produces reactive oxygen and nitrogen species (RONS), which include both long-lived species (such as NO₂ ⁻ NO₃ ⁻, H₂O₂) and short-lived species (such as •OH, O⁻ ₂, ONOOH) that play crucial roles in enhancing biological growth processes [11–13]. These RONS are essential for triggering physiological processes that promote seed germination and tissue growth [8]. The effects of plasma exposure on various stages of seed sterilization, decontamination, enzyme activity, seed dormancy, sprouting, and seedling growth were earlier reported by Bormashenko et al. (2012) [14].

Several plasma-based methods have been developed for seed processing, including low-pressure plasma, microwave (MW) plasma and radio frequency (RF) plasma. Researchers have analyzed different gas plasmas, such as air, oxygen, helium, and nitrogen, to understand their effects on seed characteristics. Gebremedhin et al. (2019) [15] investigated the effects of atmospheric pressure plasma, produced by multi-hollow surface dielectric barrier discharges, on the physical characteristics of peanuts during a one–15-min treatment period, using a 10–40 W AC power source. This study provides an understanding of how different plasma operating conditions during plasma treatment might affect the specified measurements and sensory aspects of peanuts. Li et al. (2016) [16] investigated the impact of cold plasma treatment on seed germination, growth, and peanut seeds yield using a frequency of 13.56 MHz with different power consumptions from 60 W to 140 W. Song et al. (2023) [17] evaluated the effects of a surface dielectric barrier discharge (SDBD) device on the sprouting and growth of peanuts. Kheto et al. (2024) [18] reported that the atmospheric cold plasma treatment significantly enhanced guar bean seed germination, chlorophyll content, and nutritional quality, while higher plasma intensity adversely affected germination. Previous studies have established that plasma power is a critical control parameter in cold plasma-based seed treatment, as insufficient power fails to generate adequate RONS to trigger physiological responses, whereas excessive power can induce thermal stress, surface damage, and oxidative degradation of seed tissues [19]. Despite this understanding, a clear mechanistic understanding of optimal power-time operating windows remains lacking, particularly for short-duration treatments that minimize temperature rise while retaining plasma efficacy. In particular, the short-term effects of momentary plasma exposure on seed surface properties and chemical characteristics have not been sufficiently explored. Most experimental configurations locate seeds on the grounded electrode, where the density and energy of reactive plasma species are relatively low. Positioning seeds within the active plasma zone, especially near the powered electrode, allows exposure to higher-energy electrons and reactive species, thereby strengthening plasma-surface interactions [20–22].

Consequently, regulating the temperature during the cold plasma treatment could help to further improve the quality parameters of the final product. The existing studies predominantly rely on continuous AC or unipolar DBD systems, minute-scale exposure times, and grounded seed configurations, with limited control over thermal effects and plasma energy distribution [13]. In contrast, the present study employs a low-power bipolar pulsed DBD system to achieve ultra-short peanut seed treatments (≤50 s) under controlled low-temperature conditions, while simultaneously linking plasma diagnostics to physicochemical, biochemical, and biological responses. This combination of excitation mode, exposure duration, and diagnostic integration represents a distinct experimental framework not previously reported. Short-duration plasma treatments under controlled low-temperature conditions, therefore, represent a promising strategy for improving seed quality while avoiding plasma-induced damage. However, achieving such precise control requires appropriate power excitation modes and reactor configurations.

It is to be mentioned that the bipolar pulsed-powered DBD plasma exhibits advantages over others due to its ability to utilize ‘memory effects. Because of “memory effects,” if DBD is driven by a high-frequency voltage AC power supply, the effects tend to ignite the next discharges in a subsequence one-half cycle at the locations where the previous discharges have already struck in the previous half cycle with opposite polarity [23]. In case of unipolar DBDs, the release of saturation points of the accumulated charged particles on the dielectric surface in the preceding discharge is critical for sustaining the unipolar DBDs. In bipolar DBD, memory effects ignite subsequent discharges in opposite polarities, leading to more efficient energy transfer and sustained plasma generation compared to unipolar DBD. It has been observed that continuous wave operation can often result in issues like overheating and low energy efficiency. The utilization of pulsed power excitation is considered a viable option due to its ability to generate exceptionally high levels of instantaneous power density and lower electric field, resulting in enhanced electron acceleration, improved energy efficiency, improved plasma characteristics and multichannel discharge, making it preferable for various applications. Although DBD plasma has been widely explored for seed treatment, studies employing low bipolar pulse-power driven DBD systems, particularly for peanut seeds, remain limited. Furthermore, the immediate effects of short-duration bipolar pulsed DBD exposure on seed surface morphology and chemical characteristics have not been systematically investigated. Unlike conventional placement on the grounded electrode, positioning seeds in the active plasma region near the powered electrode can further enhance plasma-seed interactions [24].

This work aims to develop a low power, bipolar pulsed DBD-based ACP system and to investigate its short-duration effects on peanut seeds. The novelty of this work lies in (i) employing a bipolar pulsed power supply to precisely control plasma characteristics, (ii) optimizing plasma exposure time to achieve effective seed activation while maintaining low processing temperatures, and (iii) systematically correlating plasma diagnostics with seed physicochemical, biochemical, and biological responses. Plasma diagnostics using optical emission spectroscopy are employed to identify reactive species, while the effects of ACP treatment on germination parameters, seed surface properties, antioxidant activity, and morphology, are evaluated. This integrated approach provides fundamental insight into plasma-seed interactions and demonstrates the potential of short-duration ACP treatment as a sustainable strategy for enhancing seed germination and early seedling development. For clarity, Table 1 summarizes representative studies on plasma-assisted seed treatment, comparing the plasma sources, major findings, limitations, and the specific novelty of the present study in relation to previously reported approaches.

TABLE 1. Comparison of studies on atmospheric-pressure cold plasma treatment of seeds.

2 Materials and methodology

2.1 Plasma source and its characteristics

A scalable and efficient device has been developed to treat large volumes of seeds, as depicted in Figures 1a,b which illustrates the experimental setup with highlighting the powered electrode, grounded electrode, dielectric barrier, plasma treatment zone, and seed exposure region. This system consists of an ACP reactor, spectroscopic system, and an electrical power supply. Designed for high-throughput and uniform seed treatment, the ACP source included stator and rotator electrodes. The stator electrodes consist of an aluminium rod, 200 mm long and 15 mm in diameter, with a 1.5 mm thick dielectric material (dielectric constant 2.1). The rotator electrode, a hollow aluminium rod, has the same dimensions as the stator. Plasma is generated using a high-voltage pulsed power supply operating in the range of 1 kV–9 kV, 2 A, and 20 kHz, applied between two parallel electrodes. The dielectric-coated stator electrode is connected to the output-terminal of the power supply, while the counter electrode is grounded. The electrodes, configured as parallel cylindrical rods with a 1 mm gap in a circular arrangement, enable uniform plasma treatment. This design supports large-scale seed treatment, making it ideal for enhancing agricultural efficiency and productivity.

For plasma treatment, peanut seeds were uniformly distributed in a single layer within the active plasma zone near the powered electrode, as indicated in Figures 1a,b. The circular electrode configuration and consistent inter-electrode spacing ensured spatially uniform plasma generation across the treatment region. Exposure uniformity was further maintained by treating all seeds under identical electrical conditions (voltage, pulse frequency, duty cycle, and treatment duration). Plasma treatment uniformity was indirectly evaluated through reproducibility and spatial consistency of treatment outcomes, including seed wettability, surface morphology, and germination parameters across replicate experiments. The low variation observed in these measurements confirms homogeneous plasma exposure and reliable treatment conditions. It is to be emphasized that the seeds were positioned near the powered electrode rather than the grounded electrode because the plasma characteristics in a DBD system are strongly asymmetric with respect to electrode polarity. The region adjacent to the powered electrode experiences higher local electric field strength, increased microdischarge activity, and enhanced generation of reactive plasma species compared to the grounded side.

The DBD typically operates in the air by generating multiple tiny filaments that are uniformly distributed over the entire dielectric layer. The UV photons, excited species, and radicals that make up the dynamic plasma interact with the seed surface and alter the surface energy. A high-voltage probe (Tektronix P6015A) was used to measure the discharge voltage, and a Pearson TM current monitor model 110 (current transformer CT) was used to measure the discharge current. A digital oscilloscope was used to monitor and analyze the current and voltage signals (Tektronix MDO3014, 100 MHz).

Optical Emission Spectroscopy (OES) analysis was performed using an Andor Shamrock SR-500i-B1 spectrometer equipped with a 10 μm entrance slit, a 600 grating/mm diffraction grating, and a spectral resolution of 0.02 nm, covering the wavelength range of 200–900 nm. The emitted light from the plasma discharge was collected and transmitted to the spectrometer through an optical fiber cable (Ocean Optics) with a core diameter of 200 μm, positioned 3 cm from the plasma discharge region. This setup enabled the identification of plasma species generated during the discharge process.

2.2 Hydroxyl radical, nitrite and nitrate measurement

To elucidate the plasma chemistry responsible for seed surface modification, major RONS generated in the plasma were measured using a standard procedure [17, 26]. The concentrations of NO₃ ⁻ and NO₂ ⁻ were measured using standard calibration curves. For NO₂ ⁻, the calibration equation was y = 0.0483x + 0.0009, covering a range of 50–300 μg/L. For NO₃ ⁻, the equation used was y = 0.0525x + 0.0537, applicable to a range of 1–5 mg/L. OH• concentrations were determined using Terephthalic acid (TA), with the unknown values derived from the calibration curve y = 22.11x – 32.05. TA reacts with •OH radicals to produce 2-hydroxyterephthalic acid (HTA). The fluorescence of HTA was recorded at 425 nm using a fluorescence spectrophotometer (LS 55, PerkinElmer, United States) after excitation at 315 nm. The concentrations of •OH, NO₃ ⁻, and NO₂ ⁻ were measured in a liquid collection medium exposed to the plasma under the same operating conditions as those used for seed treatment. These measurements provide an indirect assessment of the reactive oxygen and nitrogen species (RONS) generated by the DBD plasma and the chemical environment produced during plasma discharge. Although the concentrations do not directly represent the gaseous species or their flux at the dry seed surface, they serve as a comparative indicator of plasma chemistry under identical experimental conditions and help establish the relationship between plasma operating parameters and the observed physicochemical and biological responses of the treated seeds.

2.3 Atmospheric cold plasma (ACP) treatment

Raw peanut seeds (Arachis hypogaea L.), a widely cultivated groundnut species in India, including Rajasthan were procured from a local vendor at the IIT Jodhpur market and stored in a cool, dry place until use. For this study, the farmer-saved peanut landraces were collected from local growers in the Jodhpur region of Rajasthan, India, and were used in the experimentation. The seeds belonged to the Spanish (bunch-type) category, which is extensively cultivated in western Rajasthan. Morphological characteristics included medium-sized, spheroidal kernels with pink to light-brown seed coats and plants exhibiting an erect growth habit. The initial moisture content of the seeds prior to treatment was 8% (wet basis), consistent with standard trading and storage moisture levels for desiccated peanut kernels intended for processing and planting. To minimize biological variability, only healthy, intact, and visually uniform peanut seeds with similar size, shape, and seed coat appearance were selected for the experiments. All control and ACP-treated samples were prepared from the same seed batch, and the germination experiments were conducted under identical environmental and experimental conditions. Thus, any inherent variability associated with farmer-saved seeds was expected to be randomly distributed between the experimental groups. For the germination study, both ACP plasma-treated and untreated seeds were soaked in 20 mL of deionized (DI) water for 24 h and then placed in a 90 mm Petri dish covered with two layers of filter paper for measuring germination characteristics. For each experiment, hundred seeds were uniformly distributed and watered every day with 10 mL of DI water. Seed germination was monitored at different intervals of time, i.e., the first day, third day, and seventh day. Germination was counted once the seedling length was equal to or greater than half the seed length [27].

Subsequently, germination characteristics, vigor index, wettability, water activity, bioactive compounds, and various surface properties were analyzed to evaluate the impact of ACP seed priming. To ensure reliability and minimize experimental error, all tests were conducted in triplicate. The surface temperature of the peanut seeds was measured during ACP treatment using a non-contact infrared thermometer.

2.4 Influence of ACP seed priming on germination characteristics

2.4.1 Physicochemical analysis

To analyze the effect of ACP seed priming on the germination characteristics, 100 peanut seeds were physically inserted into the active plasma zone of the dielectric barrier to ensure uniform treatment. Peanuts were pretreated for 0 (control), 10, 20, 30, 40 and 50 s at an optimized value of applied voltage (9 kV) and frequency (20 kHz). The percentage of Germination Potential (percentage of seeds germinated on the third day), Final Germination Percentage (Germination rate (G R, Germination Index (Ist, third, and seventh day after sowing) and Vigor Index were calculated for each day, using the formula given below [28, 29];

Germination Potential % of seeds germinated on 3 rd day = number of seeds germinated on 3 rd day total number of seeds × 100 % (1)

Final germination Percentage = number of seeds germinated in 7 d total number of seeds × 100 % (2)

Germination Index Ist , 3 rd , 7 th day = ∑ number of seeds germinated on t day germination days (3)

Vigor index = germination index × total length (4)

To calculate wettability (percentage increase in seed mass), initially, the weight of the dry seeds was measured (m 0) then again, after 24 h of soaking in distilled water, the weight of the soaked seeds was measured (m 1). Then, the following modified equation [30] was used to calculate the water uptake.

Wettability % = m 1 − m 0 m 0 × 100 % (5)

Where m 0 = Initial weight of seed, m 1 = weight of seed after 24 h of soaking.

For accurate measurements of water activity, the seeds were gently wiped using absorbent paper and then measured using Rotronic 8303 water activity meter [31].

The seed reserve utilization was measured according to methods reported in [32, 33].

Seed Reserve Utilization g g = w 1 − w 2 w 2 (6)

Where w 1 = Initial weight of seed, w 2 = Dry weight of seed

To measure the seed electrical conductivity, initially, peanut seeds were immersed in DI water to leach or transfer ions from the seed membrane into the liquid, which was measured by an electrical conductivity meter (Eutech CON 700).

2.4.2 Influence of ACP seed priming on surface characteristics

2.4.2.1 Seed surface morphology

Field Emission Scanning Electron Microscopy (FESEM) (Aperio 2 Thermofisher) technique was used to observe microstructural alterations on the surface of the peanut seeds. Double-sided adhesive carbon tape was used to attach seed samples to aluminium specimen stubs. The gold coating was applied to the seeds to eliminate surface charging. FESEM pictures were captured at a magnification of 5,000X and an accelerating voltage of 10 kV for all the samples.

2.4.2.2 Seed surface hydrophilicity

A contact angle goniometer (Kyowa DMe- 211 Plus) was used to determine the static contact angle of untreated and treated peanuts. Measurements were performed by pouring 2.5 µL of distilled water onto the seed surface. The average value was then investigated by measuring the contact angles at different positions of the seed surfaces.

2.4.2.3 Chemical composition analysis

Infrared (IR) spectroscopy is a vibrational spectroscopic method that relies on substances that excite molecular bond vibrations to absorb infrared radiation. The spectra of peanut seed samples to check intensity variation were recorded using Fourier-transform infrared spectroscopy (Vertex, 70V + PMA50) from the 4,000 cm⁻¹ to 400 cm⁻¹ range at ambient temperature.

FTIR measurements were carried out using the KBr pellet method. For sample preparation, 1 mg of finely crushed peanut seed sample was thoroughly mixed with 150 mg of spectroscopic-grade KBr using an agate pestle and mortar. The mixture was compressed into pellets of 13 mm diameter under a pressure of 15 tonnes for 30 s. Each measurement was performed in triplicate to ensure reproducibility.

2.4.2.4 Color variation with different treatment times

The Color Reader (CR6, 3nh) was used to measure the change in colour (ΔE) from the (Llightness/darkness) (a redness/greenness) (bredness/greenness) value of the untreated and treated peanut seeds samples, using the CIE (Lab) system (D65 illuminant and 10° standard observer) [31, 34]. The total colour difference (ΔE) was calculated using Equation 7:where ΔL∗ is the difference between L plasma treated and L control; Δa∗ is the difference between a plasma treated and a control; and Δb∗ is the difference between b plasma treated and b control.

Δ E * = Δ L * 2 + Δ a * 2 + Δ b * 2 (7)

2.4.2.5 Antioxidant capacity of sprouts

ABTS· and DPPH· assays were used to evaluate the antioxidant activity of peanut seeds sprout extracts [35]. The data was presented as the Trolox equivalent in milligrams per Gram of dry weight (mg Trolox/g DW). The changes in the free radical scavenging potential of extracts with plasma treatment were determined by ABTS· and DPPH· assays as described by previous investigators [36].

% ABTS / DDPH = A B − A A A B × 100 % (8)

Where A_B and A_A indicate the absorbance of the blank at t = 0 min and absorbance of the antioxidant at t = 30 min, respectively.

2.5 Elemental composition analysis by ICP-MS

The inductively coupled plasma-mass spectrometer (ICP-MS Agilent, 7,850) was used to analyze the elemental composition of peanut seeds. One-gram samples of untreated and treated sprouts were taken in a glass beaker with a volume of 100 mL. The samples were left overnight with a mixture of 6 mL HNO₃ (Sigma Aldrich) and 2 mL H₂O₂ (Sigma Aldrich). The next day, the mixture was digested in a microwave digestor for 24 h. Then the residue was filtered with a 0.2 µm syringe filter, and the solution was transferred to 100 mL plastic standard flasks and aspirated in ICP-MS.

2.6 X-ray photoelectron spectroscopy (XPS)

The elemental composition of peanuts before and after plasma treatment was analyzed using Small Spot XPS (ESCA + Omicron Nano Technology), which features Dual Beam Charge Neutralization, fully integrated software control and automation, and rapid quantification using MultiPak or CASA XPS. The binding energy scale of the spectra was calibrated using the C1S main peak, set at 284.5 eV. To ensure that the substrate did not contribute to the analysis, multiple seeds were arranged to fully cover the examined area (0.5 × 0.5 cm).

2.7 Statistical analysis

The statistical analysis was performed using the web-based Agriculture Statistics Software Package (WASP 1.0). A one-way analysis of variance (ANOVA) was employed to analyze the data. The significance among the samples was compared at p < 0.05. The data is reported as the mean value ±standard error (SE) of the three replicates.

3 Result and discussion

3.1 Plasma source electro-optical characteristics

Figure 2 shows a typical V-I characteristic and instantaneous power vs. time at a voltage of 9 kV and a frequency of 20 kHz. The following relationship is used to estimate the average power consumption of DBD plasma.

P a v g = 1 T ∫ 0 T P ( t ) d t (9)

The instantaneous power P(t) is calculated by multiplying the instantaneous voltage V(t) and current I(t) by the oscillation period T. The electron density can be approximated from the V-I curve using the following relationship [37].

n e = J e μ e E = I r m s A e μ e E (10)

Where J is the current density, A is the cross-sectional area of the powered electrode, I r m s is the root mean square current, E is the electric field between the electrodes, e is the electronic charge, and μ e is electron mobility, i.e., 552 cm²/V.s in the case of nitrogen [7]. The current density was calculated using the geometric area of the powered electrode facing the grounded electrode, assuming that the plasma discharge was approximately uniformly distributed over the active electrode surface. Therefore, the calculated electron density should be regarded as an approximate estimate, since the effective discharge area may differ from the geometric electrode area. More accurate determination of the effective discharge area would require spatially resolved plasma diagnostics, such as ICCD or high-speed optical imaging. The operational condition results in approximately the average power consumption of 4 W and an electron density of 4.19 ×10⁹ particles/cm³, respectively.

The dissipated electric power of the ACP-DBD was calculated using voltage-current (V-I) characteristics. The source was operated with an on-time (T_on) of 2 µs and a shut-off time (T_off) of 48 µs, corresponding to a pulse repetition frequency (PRF) of 20 kHz and a duty cycle of 4% (duty ratio = 0.04). The average discharge power was determined using the instantaneous voltage-current (V- I) method by integrating the product of the applied voltage and discharge current over one pulse cycle [38–40]. Direct time-resolved V-I integration is particularly relevant because the ACP-DBD reactor used a bipolar pulsed power source, which results better in per-pulse power characterization.

OES is a rapid, real-time, and non-destructive method used to analyze the radicals, active species, atoms, and ions created in plasma. The optical emission spectra of ACP in the 200–900 nm wavelength range are shown in (Figure 3). The excited species produced in atmospheric air plasma were investigated by the OES technique. N₂ second positive system (SPS) (C³П_u–B³П_g) peaks at (296, 315.7, 337, 353, 357.2, and 380.3) and N₂ first positive system (FPS) (B³П_g–A³П_u ⁺) peaks in the range (500–700) nm. Also, N₂* first negative system (FNS) emissions at wavelengths of (399.6 and 405) nm [41]. O(I) also get confirmed at wavelengths 716 and 752 nm. Non-thermal discharges generate RONS that improve the rate of germination of seeds and overall plant growth, which is explained in the latter part of this research.

NO generated during discharge is considered an important precursor for the formation of nitrate ions (N O 3 − among the long-lived species in atmospheric air plasma. N O 3 − may be produced by electron impact ionization processes of nitrogen (N₂), oxygen (O₂) and water H₂O in the gaseous state, as shown in Equations 11–20 [42]. In particular, the reaction between atomic nitrogen and hydroxyl radicals to form NO is represented by Equation 17.

e + N 2 → e + 2 N (11)

e + H 2 O → e + H + OH. (12)

e + O 2 → 2 O . + e (13)

O . + O 2 → O 3 (14)

O . + H 2 O → O H · + O H . (15)

e . + O 2 + N 2 → 2 N O . + e (16)

N + O H → N O + H (17)

N O + O → N O 2 (18)

N O 2 + e → N O 2 − (19)

N O 2 + N O 2 − → N O 3 − + NO (20)

The intensity and concentration of RONS species produced mainly depend on plasma-generating parameters such as applied voltage, discharge frequency, and the gap between dielectric and gas used for discharge [43]. The applied voltage at an optimal frequency with a fixed gap results in producing an ideal discharge for exciting and dissociating the gas molecules to produce dynamic reactive species. The result of the above phenomena was observed after interaction with the seed coat at the optimal value of plasma parameters. Also, when the atomic oxygen reacts with water mist in air converts into hydroxyl ions (OH⁻) (Equation 15), and the reaction with nitrogen molecules produces reactive nitrogen species (RNS), viz. N₂ ⁺, NO^**.**, NO₂. In atmospheric air plasma, short-lived species such as atomic oxygen (O) and hydroxyl radicals (•OH) are rapidly consumed, while long-lived species, including ozone (O₃) and nitrogen oxides (NO_x), persist due to their relatively lower reactivity and successive energy-transfer and collision processes [44]. These long-lived RONS play a key role in modifying the seed coat through surface etching and oxidation, thereby enhancing wettability and water uptake, which ultimately promotes improved seed germination and early seedling development. As shown in Figure 3b , only a negligible increase in seed surface temperature was observed after plasma treatment, confirming that the ACP process is non-thermal and that the observed biological responses are predominantly associated with reactive plasma species rather thermal effects.

3.2 Impact of ACP on physicochemical attributes of peanut seeds

The effect of ACP treatment on the germination characteristics of peanut seeds varies with different treatment times, is given in Table 2. ACP treatment for 10, 20, 30 and 40 s significantly (p < 0.05) enhanced both germination potential and final germination percentage. Germination potential at 40 s increased by 11.09% and the germination rate increased by 9.67%. Treatment had no significant (p > 0.05) effect on the germination index at treatment times of 10 and 20 s; however, 40 s treated seeds led to an increased germination index by 12.69% (p < 0.05). The vigor index significantly increased by 61.77% (p < 0.05).

TABLE 2. Influence of ACP on the germination characteristics of peanut seeds.

The superscript letters (a–f) indicate statistically significant differences among treatments within the same column. Values with different superscript letters are significantly different at p < 0.05, whereas values sharing the same superscript letter are not significantly different.

The effects of ACP on peanut seedling growth are shown in (Figure 4). The germination length of ACP plasma-treated seeds was significantly increased (p < 0.05) as compared to the control Figure 5a. The increment in germination length of 40 s treated seeds was maximum (45.13%) as compared to the control on the seventh day. The increase in germination parameters can be linked to the process of seed etching and chemical modifications, which have improved the transportation of nutrients and water to enhance germination and growth. According to recent reports, plasma-treated seeds often germinate more quickly when exposed to water vapour or submerged in liquid water [14]. A statistically significant difference (p < 0.05) in wettability was observed between the control and all ACP plasma-treated samples, as shown in Figure 5b. The maximal gain in wettability was reported for 40 s treated seeds (96.34% ± 0.99%) as compared to control (74.69% ± 2.11%) on the seventh day. It is well-accepted that increasing the wettability of a seed is the first step towards better germination and plant growth [45]. The presence of active species on the surface of seeds improved germination, surface oxidation and hydrophilicity. According to Los A et.al [46], seed germination is affected by changes in the wettability of the seed coat, enhanced water absorption, erosion of the seed coat, and hormonal activities related to plant transduction and enhancement [46].

For germination and plant growth, water uptake plays an important role in seed germination because it provides enough water to soften seed coatings, increase seed electrical conductivity, supply dissolved oxygen for embryo expansion, and boost protoplasm activities [47]. The increased water activity values indicate that nutrients were delivered to improve seed germination and growth. The water activity of the seeds was measured to link it with the enhanced water uptake after ACP treatment. Prior to plasma exposure, sprouts exhibited a fresh weight of 2.17 ± 0.012 g and a dry weight of 0.97 ± 0.022 g. Following treatment, the fresh weight reached 2.54 ± 0.018 g, and the dry weight increased to 1.18 ± 0.015 g, reflecting an overall improvement in biomass accumulation.

The water activity of the peanut seeds was significantly increased (p < 0.05) for ACP-treated seeds, as shown in Figure 5c. The maximum water activity was reported for 40 s, while 50 s treated seeds became stagnant for water absorption. Plasma treatment can remove the wax layer and make the surface more hydrophilic, which is beneficial for growth. However, due to the effect of more treatment time in our case, 50 s, adverse effects also occurred, i.e., hydrophobic recovery, which resulted in low water intake [48]. This hydrophobic recovery is likely associated with post-plasma surface relaxation phenomena, including reorientation of polar functional groups toward the bulk, migration of low-molecular-weight species, and partial reorganization of the seed surface following prolonged plasma exposure. Such processes have been widely reported in plasma-treated polymeric and biological materials and are commonly attributed to surface aging effects after plasma treatment [49]. The seed’s ability to absorb water may be impaired, or it may get stagnant if the damage causes a physical barrier [50]. The surface damage can be excessive if the concentration or duration of exposure is too high.

Moreover, excessive ACP exposure can also affect cell membranes, allowing intercellular molecules such as sugars and electrolytes to escape [51]. These leached substances increase the electrical conductivity of seed leachate (imbibition solutions), i. e., water ACP-treated seeds, indicating the vitality of the seeds. The electrical conductivity of seed leachate was measured to assess ion leakage from the protoplast space of seeds into solution on the first, third, and seventh day. There is an increase in seed electrical conductivity with treatment time on the seventh day, i.e., 968.36 ± 39.36 μS/cm for treated compared to untreated seeds, i.e., 428.08 ± 9.5 μS/cm, as shown in Figure 5d. A statistically significant difference (p < 0.05) in seed electrical conductivity was observed between the control and ACP-treated samples. Results showed that the seed electrical conductivity of seeds treated with ACP was much higher than that of untreated seeds. This indicates that plasma treatment of peanut seeds etched the seed surface, increasing the permeability of the peanut seeds cuticle. The water permeability of the peanut seeds coat increases due to erosion of the hydrophobic wax layer, as reported for Andrographis paniculata seeds exposed to ACP [52]. The loss of the cell membrane layer may also increase the conductivity of leachate. Damage to the cell membranes of seeds from intense plasma or chemical treatment might further result in the leakage of carbohydrates and electrolytes used to increase seed germination [53]. The imbibition solution’s electrical conductivity and pH can be used as indicators of the seed’s exudation of chemicals. It also accelerates the use of seed reserves during early seedling growth. After ACP treatment, seed reserve utilization increased to 10.89% as given in Table 3. The effects of plasma-generated reactive oxygen and nitrogen species are strongly dependent on the treatment dose. Moderate levels of reactive species promote seed germination by enhancing water uptake, activating antioxidant defense mechanisms, and stimulating cellular signaling pathways. In contrast, prolonged plasma exposure may generate excessive reactive species that overwhelm the cellular antioxidant system, leading to oxidative stress, membrane lipid peroxidation, protein and DNA oxidation, reduced metabolic activity, and impaired seed viability [54]. Therefore, careful optimization of plasma treatment parameters is essential to maximize the beneficial effects of plasma while minimizing potential oxidative damage.

TABLE 3. Influence of ACP on seed reserve utilization of peanut seeds.

The superscript letters (a–c) indicate statistically significant differences among treatments within the same column. Values with different superscript letters are significantly different at p < 0.05, whereas values sharing the same superscript letter are not significantly different.

Cold plasma plays an important role in increasing seed germination, as demonstrated by the effects of treatment time and voltage on RONS, including hydroxyl radicals, nitrate, and nitrite, and their relationship to germination and vigor index. As can be seen from the data shown in Figures 6a–f, the RONS generated by cold plasma are likely associated with the observed modifications of the seed surface. The optimal concentrations of hydroxyl radicals (102.42 μM), nitrate (61.86 mg/L), and nitrite (1,684.06 μg/L)) were achieved for applied voltage of 9 kV and 40 s of treatment time, which coincided with the highest germination index and vigor index, suggesting that these reactive species re-associated with enhanced seed priming and seedling growth. This study sheds light on the role of ACP in sustainable crop production, emphasizing the need to fine-tune treatment parameters to control RONS. Optimizing the treatment parameters to regulate RONS levels was important. These observations suggest that ACP-generated RONS contribute to enhanced germination through plasma-induced modifications of the seed surface, although direct mechanistic evidence was not obtained in the present study.

3.3 Influence of ACP on the morphological and chemical properties of the seeds

Water contact angle (WCA) measurements were used to investigate the surface wettability of peanut seeds. Hydrophilicity is increased and water distribution is enhanced on plasma-treated seeds because of the etching caused by ACP treatment [55]. Several studies have shown enhanced hydrophilicity after cold plasma treatment, such as high-impedance micro-corona DBD plasma was used to turn rice into a super-hydrophilic material [56]. In another work, treatment with low-pressure gaseous plasma rich in vacuum UV (VUV) radiation turns polytetrafluoroethylene into super-hydrophilic [57]. In our analysis, ACP treatment has played a significant role in reducing WCA on seed surfaces from 103°(control) to 47.5° (treated), as shown in Figure 7. Accordingly, the hydrophilicity of seeds is enhanced by ACP treatment, which raises the density of polar groups on the seed surface.

To determine the chemical changes caused by plasma on peanut seeds’ surfaces, we have obtained the FTIR spectra of untreated and treated peanut seeds at different treatment times as shown in (Figure 8) which shows there is no change in peaks before and after plasma treatment.

There is a broad peak in the region 3,350–3,450 cm^–1 that is characteristic of the cellulosic -OH groups in peanut seeds [58]. Figure 8 shows the band intensities at 3,442 cm^–1(O–H), 1,635 cm^–1(C=O), 1,228 cm^–1 (C–O–C), and 2,925 cm^–1 (C H 2). The wettability of the seeds was improved by an increase in the intensities of oxygen-related and nitrogen-related components, leading to increased water uptake and ultimately enhanced germination [59]. The peanut seeds cultivars’ seed coats were analyzed by FTIR to determine the active components, like phenols and tannins, based on their characteristic functional group peaks (fingerprints) in the infrared spectrum. After analysis wide variety of phenols, alkanes, amides, esters, carboxylic acids, amino acids, alcohols, and flavonoids were found in the peanut seeds coat analyses [56, 60].

Field Emission Scanning Electron Microscopy (FESEM) was used to examine the surface morphology of untreated and ACP-treated peanut seeds. The untreated seed surface (Figure 9a) exhibits a relatively compact and smooth morphology with a limited number of shallow cracks. After ACP-treatment, progressive morphological changes were observed as a function of treatment duration. At a treatment time of 10 s (Figure 9b), the surface shows the onset of small cracks and shallow fissures compared to the control (untreated sample). With increasing treatment duration to 20 and 30 s (Figures 9c,d), the density length of cracks increased. accompanied by the appearance of localized surface irregularities. At 40 s (Figure 9e), the cracks became wider and deeper, indicating substantial disruption of the surface layer. Further extension of the treatment time to 50 s (Figure 9f) resulted in pronounced fissures and a highly fragmented surface structure. Plasma treatment caused erosion at the level of the pericarp’s upper epidermis, resulting in a rougher surface than the control seeds. The active plasma species induced the etching and erosion of the seed surface, increasing the wettability and permeability of the peanut seed coat. In treating Andrographis paniculata with pressure air plasma, Tong et al. (2014) found similar results [61]. Bormashenko et al. (2012) also observed that air plasma treatment might improve the wettability of lentil, wheat, and bean seeds due to surface modifications and oxidation of seed surfaces during plasma treatment, which improved water imbibition [14].

In our study, ACP treatment effectively eroded the hydrophobic wax layer on the peanut seed coat, leading to a measurable increase in surface hydrophilicity, as evidenced by enhanced wettability and improved water uptake. FESEM analysis revealed significant chemical and morphological alterations on the pericarp surface, likely due to etching and degradation caused by plasma exposure. The surface morphology of the peanuts changed markedly from a relatively smooth texture to one characterized by numerous pores and fissures. This transformation became more pronounced with increasing treatment duration and plasma intensity, resulting in progressively rougher surfaces. The disruption of cellular structures and the release of intracellular content enhanced mass transfer, facilitating the ingress and diffusion of moisture vapor within the peanut seed tissue. These processes contributed to the breakdown of larger surface globules and the formation of micropores, as illustrated in Figures 9b–f.

Color is another important parameter for the physical appearance of food components since it influences consumer preferences and is responsible for a consumer’s final purchasing choice [62]. The color of peanuts treated by various techniques is significantly influenced by the processing parameters during which the treatment is administered. Color values were measured in terms of their L, a, and b* coordinates (lightness, redness, and yellowness, respectively) across a range of plasma conditions. The values L, a, b* for untreated peanuts are 34.49 ± 0.89, 4.64 ± 0.74, and 1.92 ± 1.28, respectively. The surface color of peanuts changed a little after being exposed to plasma treatment. Table 4 indicates that all treatments had ΔE values less than 6, suggesting that the colors were not noticeably different from untreated peanut seeds. ACP treatment can lead to minor changes in the color or bleaching of the seed coat as a result of modifications in the surface structure. Plasma treatment has been shown to improve the brightness and uniformity of seed color in some instances, maybe by eliminating surface impurities or enhancing light reflectance characteristics. Nevertheless, an abundance or extended use of plasma treatment may result in unfavourable alterations in color, such as darkening or browning, that might impact the seeds’ visual attractiveness or market value. Hence, meticulous tuning of plasma treatment settings is necessary to get the intended color effects while safeguarding seed quality in peanut seed production. Additional investigations are required to comprehend the precise mechanisms that cause color changes in peanut seeds as a result of plasma treatment.

TABLE 4. Influence of ACP on color parameters. Results are expressed as ± standard error.

3.4 Influence of ACP on antioxidant activities in peanut sprouts

Antioxidants are compounds that provide electrons to injured cells to prevent and stabilize damage caused by free radicals. Antioxidants are believed to act on DPPH^• and ABTS^•+ due to their capacity to donate hydrogen. DPPH^• and ABTS^•+ scavenging assays are standard spectrophotometric methods used to measure the antioxidant capabilities of substances. ACP treatment did not result in a significant difference in the DPPH^• and ABTS^•+ scavenging activities of peanut sprouts, as indicated in Table 5 (p > 0.05). However, there were slight increments in the DPPH^• and ABTS^•+ activity post-plasma treatment. These findings showed that the levels of phenolic compounds rose as plasma treatment increased up to 50 s. The RONS enhanced the permeability of cell membranes in sprouts to aid in the absorption of nutrients, which can boost the overall antioxidant capacity of the sprouts. This could further help to understand the beneficial effect of plasma treatment on the plant materials for their metabolic functions. In a different study, Xu et al. (2016) assessed the antioxidant capacity of button mushrooms treated with plasma-activated water using malondialdehyde, as an oxidative stress maker, and found no significant changes [63]. In the present study, antioxidant activity was evaluated after sprout development to assess the physiological response of germinated seedlings following plasma seed priming. Immediate post-treatment measurements were not performed because the study focused on the biological outcomes of germination rather than the initial oxidative changes induced by plasma exposure. Future studies will investigate antioxidant activity both immediately after plasma treatment and during subsequent germination to distinguish direct plasma-induced effects from downstream biological responses. Although enhanced antioxidant activity was observed following ACP treatment, the underlying biochemical mechanisms were not investigated in the present study. Future work will include the quantification of total phenolic content, total flavonoid content, and other antioxidant-related metabolites to better understand the biochemical pathways responsible for the plasma-induced enhancement of antioxidant activity.

TABLE 5. Influence of ACP on antioxidant activities in peanut sprouts.

The superscript letters (a–c) indicate statistically significant differences among treatments within the same column. Values with different superscript letters are significantly different at p < 0.05, whereas values sharing the same superscript letter are not significantly different.

3.5 Influence of ACP on the elemental composition of peanut sprouts

For proper germination and growth of seeds, the optimal accumulation of elemental composition is necessary [64]. Like during the reproduction phase of the seed life cycle, there is a significant requirement for iron (Fe) [65]. Fe, Zn, and Cu are vital for seed germination function and for seed reproduction as they are involved in critical metabolic activities. Zinc is essential for the process of DNA transcription, the production of proteins, and the control of hormones. It plays a crucial role in cell division and differentiation in floral tissues and seeds.

In this study, ICP-MS analysis was used, which revealed significant alterations in the elemental composition of peanut seeds following ACP treatment, as summarized in Table 6. Elemental analysis was carried out on peanut sprouts rather than dry seeds to capture ACP-induced changes in nutrient uptake and redistribution during the active germination phase. Based on earlier germination results, the 40 s ACP-treated samples showing optimal biological performance were selected for comparison with the untreated control in the ICP-MS analysis.

TABLE 6. Macro and micro element contents (ppb) of untreated and treated peanut sprouts analyzed by ICP-MS.

ICP-MS is a highly sensitive and precise analytical technique that facilitates rapid quantification of multiple elements within a sample. Notably, the concentrations of sodium (Na), boron (B), potassium (K), calcium (Ca), magnesium (Mg), aluminum (Al), iron (Fe), and manganese (Mn) increased by 38.03%, 54.37%, 35.59%, 72.92%, 35.42%, 75.77%, 65.81%, and 6.14%, respectively, compared to untreated seeds. The observed changes can be attributed to the generation of reactive species such as ions, radicals, and excited molecules during plasma discharge, which interact with the surface of the seed. These interactions induce structural modifications that enhance nutrient uptake efficiency, thereby altering the elemental composition of the treated seeds.

Although ACP-treated peanut sprouts exhibited higher concentrations of several macro- and micronutrients, the underlying mechanism responsible for these changes was not directly investigated in the present study. The observed differences may be associated with plasma-induced modifications of the seed surface, improved water imbibition, and altered nutrient mobilization during germination. However, variations in tissue water content or biomass accumulation may also influence the measured elemental concentrations, and therefore a concentration effect cannot be excluded. Further research is need to include moisture analysis, dry-weight normalization, and nutrient uptake measurements to distinguish between enhanced elemental uptake and changes resulting from tissue water content.

3.6 Influence of ACP on surface chemistry modifications of peanut seeds

X-ray Photoelectron spectroscopy (XPS) was employed to analyze the surface chemistry modifications of peanut seeds, providing insights into the atomic composition of elements present within the top 5 nm of the surface. The survey spectrum revealed the presence of carbon (C), oxygen (O), nitrogen (N), and other elements, with varying concentrations between treated and untreated seeds. After exposure to ACP, the treated seeds exhibited a notable increase in both carbon and oxygen content compared to the control samples. The atomic composition, summarized in Table 6, indicates a predominant presence of carbon, which is expected due to the seed coat’s composition, primarily consisting of lipids and carbohydrates. Additionally, a small amount of nitrogen was detected on the surface. High-resolution C 1s and O 1s spectra, as shown in Figures 10a–c, confirmed these trends. The C 1s spectrum (∼284.8 eV) revealed an increase in oxygen-containing functional groups, such as C-O (∼286.3 eV), C=O (∼287.8 eV), and O-C=O (∼289.0 eV). Similarly, the O 1s spectrum (∼531.0 eV) showed an enhancement in hydroxyl (C-O, ∼532.5 eV) and carbonyl (C=O, ∼531.0 eV) groups, indicative of oxidation. Moreover, the emergence of an N 1s peak (∼399.5 eV) suggests nitrogen incorporation from the plasma treatment. The observed increase in oxygen-containing functional groups suggests oxidation of the outermost surface layer induced by ACP treatment. Such plasma-driven oxidation processes have been reported to involve the transformation of surface hydrocarbon groups into more oxidized species, which may be accompanied by the release of volatile by-products such CO₂ and H₂O [66, 67].

These surface modifications significantly alter the wettability, reactivity, and functional properties of the peanut seeds, which could have implications for improved preservation, processing, and potential applications in agriculture and food.

In this research, plasma treatment was done with an ACP device with momentary plasma exposure, which showed a stimulatory effect on peanut seed germination. The OES results indicate that plasma generated in our device is a rich source of RONS. Placing the seeds in the cathode area, where the electromagnetic power transfers to plasma, may intensify the presence of RONS [68]. Plasma discharge produces various excited atoms, active species, radicals, and ions that transform seeds physically and biologically [69].

The observed enhancement in germination may be attributed, at least in part, to RONS-mediated modifications of the seed-coat surface and its physicochemical properties, which are in agreement with mechanisms proposed in previous studies. Such modifications could potentially alter seed-coat permeability and facilitate the processes associated with germination. However, the present results should be interpreted as evidence of an association rather than definitive proof of cause. Establishing a direct mechanistic link between RONS-induced seed-coat modification and the observed germination response will require targeted experimental validation.

RONS can oxidize surface molecules, leading to changes in surface chemistry, increased hydrophilicity, and improved water uptake. These effects are well supported by increased seed wettability and water absorption observed in the present study. Such surface-driven mechanisms play a crucial role in facilitating oxygen and nutrient diffusion into the seed, thereby promoting germination.

In addition to surface effects, RONS are widely reported in the literature to function as signaling molecules during seed germination and early growth. Previous studies suggest that RONS may interact with phytohormones such as abscisic acid (ABA) and gibberellic acid (GA), which are key regulators of dormancy release and germination processes [70]. GA is known to promote dormancy breakdown and seedling growth, whereas ABA plays a dominant role in maintaining dormancy and regulating stress responses. While such interactions have been reported in earlier studies, it is to mention that hormone levels or signaling pathways were not directly measured in the present work. Therefore, the involvement of ABA–GA regulation is discussed here as a possible mechanism inferred from existing literature, rather than as a direct experimental outcome.

Among the different plasma exposure durations investigated, the 40 s ACP treatment produced the most significant stimulatory effect compared to other treatments. However, the ACP treatments at high treatment times had less significant influence on seed germination. Sera et al. (2021) showed that the extended plasma exposure causes deterioration in the cells of the seed. The interaction between cells and plasma could potentially cause DNA damage and cell wall fractures [71]. The results suggest that ACP is crucial in several physiological processes in seeds. These processes involve improving germination, early growth of seeds, and regulating nitrogen metabolism. Together, these mechanisms highlight the intricate role of RONS concentration in seed germination, from signaling molecules that respond to environmental cues to modulators of seed coat properties that influence nutrient absorption, ultimately contributing to enhanced growth and development in plants. However, relative atmospheric humidity may influence plasma chemistry and the generation of RONS in atmospheric-pressure plasma systems [72]. Water vapour can participate in plasma-phase reactions, thereby altering the formation and availability of reactive species. In the present study, all experiments were conducted under comparable laboratory conditions using identical plasma operating parameters and standardized procedures to minimize environmental variability. Still, fluctuations in ambient humidity may affect RONS generation and probably seed treatment. This will require future studies to monitor and control relative humidity during plasma treatment to further characterize its influence on plasma chemistry and seed responses. The surface modification on the seed surface resulting from ACP treatment has been confirmed by FESEM images. Figure 8 shows that ACP treatment has a very significant effect on the seed surface, resulting in cracks and fissures. The presence of cracks and fissures on the seed coat creates a hydrophilic surface and a permeable membrane that allows oxygen, water, and other nutrients to enter. This promotes the growth characteristics of peanut seedlings. The plasma treatment corrodes the hydrophobic wax layer, resulting in deterioration of cell membrane integrity. Filatova et al. (2013) demonstrated that plasma processing effectively eliminates a thin lipid layer on seeds, resulting in enhanced water permeability of the seed coat and improved water absorption [69]. Plasma treatment improved seed coat characteristics, increased growth rate, and enhanced water absorption; moreover, it may also affect nutrient absorption during germination. The interaction of species with the seed also stimulates the production of growth factors, alters protein structure, and affects antioxidant activity in the seed.

It is to be noted that the peanut seeds were not surface sterilized prior to ACP treatment, and the microbial population on the seed surface was not quantified. Therefore, although both the control and ACP-treated seeds originated from the same seed batch and were germinated under identical experimental conditions, the possible contribution of plasma-induced microbial decontamination to the observed improvements in germination and seedling growth cannot be ruled out. Atmospheric-pressure cold plasma is known to exhibit antimicrobial activity through the generation of RONS, UV radiation, and charged particles [73, 74]. Future studies are required combining microbiological analyses with physiological and biochemical measurements to distinguish the antimicrobial effects of ACP from its direct physiological effects on seed germination and seedling development. Plasma treatment induces various changes in functional and physicochemical properties, resulting in alterations in the elemental composition of seeds. These changes have been verified through analytical techniques such as ICPMS. Our findings suggest that enhanced absorption of elements is shown in Table 6 in peanut seeds. which were subjected to pre-treatment with ACP plasma, can be attributed, at least in part, to the stimulated growth. Changes in elemental composition result in changes in germination potential. Enhancing the efficiency of seed nutrient utilization is crucial for reducing the environmental damage resulting from the overuse of chemical fertilizers. ACP treatment is currently a crucial factor in agricultural applications. It can potentially trigger the secretion of endogenous compounds in seeds, promote seed growth, and boost agricultural output. Further, more studies are required to investigate the influence of cold plasma on molecular mechanisms during germination processes seed. Although protein content is an important nutritional indicator, it was not analyzed in the present study due to experimental constraints; and protein profiling is proposed as a key focus for future work.

The optimized cold plasma treatment improves seed germination, early seedling vigor, surface wettability, and antioxidant activity without causing thermal damage. These enhancements can lead to faster and more uniform crop establishment and improved early-stage plant performance. This type of chemical-free and energy-efficient technology can be integrated into existing seed processing lines for large-scale seed priming, offering a sustainable alternative to conventional chemical treatments and supporting eco-friendly agricultural practices. Compared with conventional seed priming techniques, such as hydropriming and chemical priming, atmospheric-pressure cold plasma offers several practical advantages, including rapid processing, elimination of chemical reagents, reduced water consumption, and minimal waste generation [75]. Though plasma systems may require a higher initial capital investment, their operational costs are relatively low due to short treatment times and the use of electricity and ambient air as the working medium. These features make ACP a promising and economically viable technology for large-scale seed treatment, although comprehensive techno-economic assessments are needed before widespread commercial implementation [39, 40].

4 Conclusion

In this study, an ACP-DBD system was successfully developed, and its electro-optical characteristics were systematically analyzed to evaluate its influence on the physicochemical properties of peanut seeds. The device demonstrated effective performance at an applied voltage of 9 kV and a frequency of 20 kHz, leading to a discharge-power of 4 W. Under these conditions, ACP treatment significantly enhanced key physiological parameters, including germination potential, growth rate, wettability, water activity, and seed electrical conductivity. These findings confirm the potential of ACP as a non-thermal, eco-friendly technology to improve seeds germination and early growth performance. Despite growing evidence supporting the beneficial effects of ACP on seeds biochemistry, the transition of this technology from laboratory to large-scale agricultural applications remains limited. This study contributes to the understanding of ACP’s efficacy and provides a foundation for future research aimed at elucidating the mechanisms by which ACP influences seeds physiology. Overall, ACP treatment presents a promising, sustainable approach for improving crop productivity and requires further investigation to enable its practical implementation in agricultural settings.

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Footnotes

Edited by: Tirtha Raj Acharya, University of Nottingham, United Kingdom

Reviewed by: Oat Bahadur Dhakal, Korea Advanced Institute of Science and Technology (KAIST), Republic of Korea

Santosh Dhungana, Tribhuvan University, Nepal

Footnotes

ACP; atmospheric pressure cold, DBD; dielectric barrier discharge, FESEM; field emission scanning electron microscopy, OES; optical emission spectroscopy, RONS; reactive oxygen-nitrogen species, DPPH; 2,2-diphenyl-1-picrylhydrazyl, ABTS; 2,2-azino-bis-3-ethylbenzothiazoline-6-sulfonic.