Sunlight to Plasma: Mimicking nature's light for smarter agriculture and crop production.

BACKGROUND: Over Earth's history, the Sun has continuously released coronal mass ejections of plasma that have flowed toward Earth, generating the need for reactive oxygen and nitrogen species (RONS) for plants. On the other hand, engineered plasma interacts with air, generating RONS. Thus, the natural process is simulated using engineered plasma (hereafter, plasma), which acts as an artificial Sun. Plasma agriculture offers a sustainable alternative by leveraging plasma-generated RONS to stimulate plant growth and generate nitrogen fertilizer through eco-friendly methods.

AIM OF REVIEW: The aim of this review is to provide a comprehensive evaluation of the use of plasma in agriculture to address global food insecurity, exacerbated by climate change and the environmental impacts of chemical-intensive farming. To tackle this issue, two methods are explored: plasma-assisted seed treatment and plasma-assisted nitrogen fixation in soil and water, referred to as plasma fertilizer. Plasma-assisted seed treatment is a pre-sowing technique designed to enhance crop yield and stress tolerance in a variety of important plant species. Conversely, plasma fertilizer serves as an environmentally friendly alternative to conventional fertilizers. This review focuses on identifying the scientific and translational priorities necessary to advance the field toward practical agricultural applications.

KEY SCIENTIFIC CONCEPTS OF REVIEW: This review is based on two interconnected concepts. The first is the biology of plasma-generated RONS, which serve as dose-dependent biochemical primers for seeds. At optimal concentrations, RONS initiate a series of responses in seeds, including modifications to the seed coat, increased activity of antioxidant enzymes, rebalancing of the phytohormones that control dormancy release, upregulation of germination-related gene expression, and epigenetic reprogramming. The second concept involves plasma-assisted C-N-H-O chemistry, in which plasma discharges convert atmospheric N2 into forms that are accessible to plants, thereby promoting overall growth. Together, these two concepts illustrate plasma agriculture's dual role in seed priming and sustainable fertilization.