From Plasma to Protection: Cold Plasma-Induced Biochemical and Anatomical Responses in Pea Plants under Salinity Stress.

Salinisation of agricultural land reduces crop productivity, often caused by poor irrigation practices and inadequate drainage that lead to salt accumulation in soil. High salinity disrupts water uptake, nutrient balance, promotes the formation of reactive oxygen species (ROS), induces stomatal closure, and damages photosynthesis, ultimately limiting plant growth and stress tolerance. Cold atmospheric pressure plasma (CAPP) has recently emerged as a promising method to mitigate salinity stress. Plasma-generated reactive particles (such as electrons, ions, metastables, reactive oxygen and nitrogen species, and UV radiation) interact with plant cells and activate signalling pathways that strengthen defence systems. In this study, we examined the effects of CAPP on pea (Pisum sativum), a glycophytic species. We measured the activity of key antioxidant enzymes, including superoxide dismutase (SOD), ascorbate peroxidase (APX), catalase (CAT), and guaiacol peroxidase (G-POX), along with photosynthetic pigment content and levels of photosystem-related proteins (D1, Lhcb, and RbcL). We also evaluated polyphenol oxidase (PPO) activity, which was linked to increased lignification and suberin deposition in roots, confirmed by anatomical analysis. Our results showed that CAPP significantly enhanced growth and biochemical responses in pea plants exposed to salt stress. In contrast, untreated salt-stressed plants exhibited significantly reduced growth together with lower enzymatic and non-enzymatic antioxidant responses. Overall, this study highlights the potential of non-thermal plasma as an innovative tool to improve plant resilience under saline conditions.