Obtaining high yields in agricultural production is essential due to the world's population growth and increased food demand. At the same time, adverse effects of agriculture on the environment need to be kept to a minimum. Low temperature plasmas (LTPs) show promise as efficient green technologies for enhancing productivity while maintaining good food quality and safety in the many steps of the food cycle. As a result, applications of LTPs in agriculture have led to creation of a new, rapidly developing field called “plasma agriculture.” Here, we briefly overview the state‐of‐the‐art of LTP applications in the complete food cycle, that is, in treatments of seeds, plants, and food.

The 2022 Roadmap is the next update in the series of Plasma Roadmaps published by Journal of Physics D with the intent to identify important outstanding challenges in the field of low-temperature plasma (LTP) physics and technology. The format of the Roadmap is the same as the previous Roadmaps representing the visions of 41 leading experts representing 21 countries and five continents in the various sub-fields of LTP science and technology. In recognition of the evolution in the field, several new topics have been introduced or given more prominence. These new topics and emphasis highlight increased interests in plasma-enabled additive manufacturing, soft materials, electrification of chemical conversions, plasma propulsion, extreme plasma regimes, plasmas in hypersonics, data-driven plasma science and technology and the contribution of LTP to combat COVID-19. In the last few decades, LTP science and technology has made a tremendously positive impact on our society. It is our hope that this roadmap will help continue this excellent track record over the next 5–10 years.

The interest in plasma-activated water (PAW) has been greatly increasing during the last few years due to its potential applications in biological and medical sciences, as well as in agriculture and food industry. The effect of PAW is caused by the reactive oxygen and nitrogen species (RONS) generated in the liquid exposed to plasma. This work reviews recent research on the formation of reactive nitrogen species (RNS) in aqueous solutions treated by non-thermal plasma. The most important chemical reactions leading to the production of these active species in the gas and liquid phase, as well as their chemistry in the liquid, correlated with their lifetime are addressed. The literature data on the most important long-lived RNS in PAW (nitrite and nitrate) and the short-lived ones (peroxynitrite and peroxynitrate) are reviewed. The reported results show that their concentrations strongly depend on the type of electrical discharge, gas composition, liquid properties and treatment conditions, and thus tuning the PAW composition over a relatively wide range can be achieved. Results on the possible application of PAW in agriculture are also reviewed. The role of RNS in this area is related to their participation in various signalling pathways in plants, which regulate metabolic processes, plant development, response to stress, etc, and thus can finally lead to enhanced germination and/or faster germination process and increase in plant growth.

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In this work we present results of two significantly different types of plasma treatment on Paulownia tomentosa Steud. seeds. In the first type, seeds were directly treated in low‐pressure plasma and then imbibed with distilled water. In the second type, an atmospheric pressure plasma was used for obtaining plasma activated water (PAW) which is then used for imbibition of seeds. The CAT activity and protein content is evaluated during 4 d following the imbibition process, i.e., immediately after the phytochrome activation and in the 3 subsequent days. Comparison of results of treated seeds to the control group allows to correlate the enzyme activity and protein content during the initial stages of germination with plasma treatment types and treatment conditions.

In this paper we show mass spectrometry results for a radio-frequency-driven micro-atmospheric pressure plasma jet (µ-APPJ) discharge obtained using a mass analyzer with triple differential pumping allowing us to sample directly in ambient atmospheric pressure environment (Hiden HPR-60). The flow of the buffer gas (mixture of helium and 1% oxygen) was 2 slm and 3 slm and the excitation frequency was 13.56 MHz. We monitored production of atomic oxygen and nitrogen in the plasma for different flows and powers given by the RF power supply. These measurements were made for energies of electrons emitted from the ionization filament below the threshold for dissociation of O 2 and N 2 . In addition to oxygen and nitrogen atoms, yields for O 2 , N 2 , NO and O 3 are recorded for different powers and gas flows. It is shown that the µ-APPJ is symmetrical and operates in α-mode. The power transmitted to the discharge was below 5 W in all measurements.

In this paper we present voltage-current-power characteristics of a plasma needle operating in the flow of helium at atmospheric pressure. In addition, we show some examples of how such a plasma affects plant tissues. In the characterization of the plasma needle, current and voltage waveforms were recorded by two derivative probes. These two probes are similar to the probes previously used by Puač et al for measuring transmitted power in low pressure CCP rf discharge. The instantaneous power was calculated from current and voltage waveforms and U -I characteristics of the discharge were determined. Regimes of operation with and without the grounding ring at the tip of the needle were considered. We have chosen two model systems to study the effect of the plasma needle on plant cells and tissues: sweet fern gametophyte (prothallus) and calli produced in vitro. Since the prothallus consists of a single layer of cells, the cytological effects could be easily examined. In addition, calli and prothallus are easy to manipulate and in vitro culture provides a possibility to work under constant and controlled conditions.