Plasma Treatment Modifies Element Distribution in Seed Coating and Affects Further Germination and Plant Growth through Interaction with Soil Microbiome.

This study investigates the impact of plasma-seed interaction on germination and early plant development, focusing on Arabidopsis thaliana and Brassica napus. The investigation delves into changes in chemical composition, water absorption, and surface morphology induced by plasma filaments generated in synthetic air. These analyses were conducted using scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). Although plasma treatment enhanced water absorption and modified surface chemistry, its impact on germination demonstrated species- and context-dependent variations. Notably, the accelerated germination and morphogenesis of seedlings in microbiome-enriched (MB+) soil could be achieved also in microbiome-deprived (MB-) soil by short-term plasma treatment of seeds. Remarkably, the positive effects of plasma treatment on early developmental events (germination, morphogenesis) and later events (formation of inflorescences) were more pronounced in the context of MB- soil but were accompanied by a slight decrease in disease resistance, which was not detected in MB+ soil. The results underscore the intricate dynamics of plasma-plant interactions and stress the significance of accounting for the soil microbiome while designing experiments with potential field application.

Surface Dielectric Barrier Discharge plasma: a suitable measure against fungal plant pathogens.

Fungal diseases seriously affect agricultural production and the food industry. Crop protection is usually achieved by synthetic fungicides, therefore more sustainable and innovative technologies are increasingly required. The atmospheric pressure low-temperature plasma is a novel suitable measure. We report on the effect of plasma treatment on phytopathogenic fungi causing quantitative and qualitative losses of products both in the field and postharvest. We focus our attention on the in vitro direct inhibitory effect of non-contact Surface Dielectric Barrier Discharge on conidia germination of Botrytis cinerea, Monilinia fructicola, Aspergillus carbonarius and Alternaria alternata. A few minutes of treatment was required to completely inactivate the fungi on an artificial medium. Morphological analysis of spores by Scanning Electron Microscopy suggests that the main mechanism is plasma etching due to Reactive Oxygen Species or UV radiation. Spectroscopic analysis of plasma generated in humid air gives the hint that the rotational temperature of gas should not play a relevant role being very close to room temperature. In vivo experiments on artificially inoculated cherry fruits demonstrated that inactivation of fungal spores by the direct inhibitory effect of plasma extend their shelf life. Pre-treatment of fruits before inoculation improve the resistance to infections maybe by activating defense responses in plant tissues.