Plasma treatment of seeds and plant cells: role of reactive oxygen and nitrogen species in formation of plantlets and embryos in non-permissive conditions

Abstract

The population growth together with constant climate changes represent a serious challenge for humankind. Additionally, the usage of the pesticides have created adverse effect on environment, which in return impact even more agricultural production. In order to comply with the demands and to adapt to the new conditions the farmers need to change or upgrade existing practices by employing new technologies. As being a promising tools in application in medicine, non-thermal (cold) plasmas (NTPs) are seen as a green alternative to conventional fertilizers in agriculture to improve yields, increase size and robustness of plants and to reduce (or eliminate) the need for pesticides [1, 2]. NTPs have rich chemistry of Reactive Oxygen and Nitrogen Species (RONS) that are formed in gas phase and, in case of water treatment, in gas/liquid interface in liquid [2, 3]. We can use NTPs in direct treatments of seeds or plant cells where samples are in contact with plasma gas phase chemistry or indirectly when treated water is applied to the biological samples. In both cases RONS (short or long-living) are responsible for triggering various mechanisms and effects in plant cells. To better understand the reasons for triggered mechanisms and outcomes (better germination percentage and speed, breakout of dormancy, creation of embryos etc.) it is important to characterize the plasma chemistry both in gas and liquid phase. We have used several atmospheric pressure plasma systems in treatments of seeds and plant cells in order to investigate the mechanisms responsible for better germination in seeds, enzyme response and formation of somatic embryos in non-permissive conditions. The mechanisms investigated were linked with the chemistry of RONS created in gas phase and/or deposited in liquid phase. Thus, we were able to acquire the data that can be used in optimization of plasma treatment processes.