Connecting the dots: from plasma physics to plant biology

Abstract

Seed germination and early seedling growth are the most sensitive growth stages for plants, especially crops, to a wide range of environmental stressors. Many efforts have been made to enhance seed germination and seedling vigor by applying various methods. As an alternative to chemical treatments, plasma technology could be one of the emerging technologies to enhance seed germination. “Plasma Agriculture” potentially offers increased production with less impact on ecosystem, giving rise to various beneficial effects such as inactivation of seed/plant-borne pathogens, enhancement and increased crop yields, and maintained good food quality. This presentation will attempt to review the effect of non-thermal plasma (NTP) and plasma activated water (PAW) on seeds and emphasis will be given to the change in the physical and biochemical properties of seeds. In treatments where seeds are in direct contact with plasma or afterglow, the surface of seeds undergoes a variety of changes. During the plasma treatment, depending on the plasma conditions, the surface is activated so other functional groups can be attached (−COOH, −COH, −COO, −NH2, −OH, −NO, etc.) leading to the changes on seeds’ surface. Similarly, PAW contains large amounts of chemically active species produced in plasma and at the plasma-liquid interface which can be transferred from the interface volume to the liquid bulk and are able to trigger desired responses in biological samples i.e. increase of germination percentage, decontamination of both seeds and plants and faster growth. Further, we will discuss the change in biochemical analysis, e.g., the variation in phytochemicals and antioxidant levels of seeds after plasma treatment with the aim to clarify the key mechanisms underlying plasmaagricultural applications in order to better understand, control, and scale up these new processes.