Cold plasma relieved toxicity signs of nano zinc oxide in Capsicum annuum cayenne via modifying growth, differentiation, and physiology

Taking functional scientific devices and metal-based nanoparticles into account, the present research was carried out to evaluate the plant (Capsicum annuum) responses to cold plasma and zinc oxide nanoparticle (nZnO) in in vitro and pot conditions. Seeds were exposed to plasma (0.84 W/cm(2) surface power densities) with three exposure times (0, 60, and 120 s) and/or two concentrations of nZnO (0 and 100 mgl(- 1)). The treated seeds were cultured in hormone-free MS medium (MS) or supplemented with 2 mgl(- 1) BA and 0.5 mgl(- 1) IAA (MSH). The seed pre-treatment with plasma enhanced a germination process and plant early growth, in contrast with the nZnO treatment. The treatment of nZnO significantly decreased the total fresh mass and leaf area in the seedlings grown in both culture media, while its growth-delaying impact was mitigated by the plasma treatment. The chlorophyll a and carotenoid were increased to 39.35 and 32% for the plasma-treated seedlings, respectively, than the control. The plasma and/or nZnO treatments acted as effective elicitors to induce the peroxidase activities in both culture media. Similarly, the activities of phenylalanine ammonia-lyase and soluble phenols were found to be significantly higher in the plasma and/or nZnO groups in both roots and leaves. Interestingly, inhibiting effects of nZnO on xylem differentiation was alleviated by the plasma treatments. In the pot condition, soaking seeds before the plasma treatment was the most effective method to affect plant growth. This is a first report reflecting the potential benefits of the cold plasma treatment to improve plant growth and resistance to the nanoparticle.