Bidirectional Effect of Plasma‐Activated Water on Fungi: Promotion and Inactivation of <i>Botrytis cinerea</i>

ABSTRACT This study investigates the bidirectional effects of plasma‐activated water (PAW) on Botrytis cinerea . At low PAW concentrations, fungal growth was promoted, with spore multiplication reaching 54.46 ± 7.16% (PAW‐10) and mycelial growth at 4.88 ± 1.83% (PAW‐2). However, at higher PAW concentrations, the effect shifted to inhibition, with spore inactivation at 41.99 ± 8.58% (PAW‐30) and mycelial growth at 7.30 ± 1.73% (PAW‐30). Critical thresholds for promotion and inhibition were observed at PAW‐18 and PAW‐5, respectively. H 2 O 2 and H + in PAW promoted spore reproduction at low concentrations and inactivated spores at high concentrations. Low PAW concentrations increased reactive oxygen species levels and enhanced cell metabolism, while higher concentrations induced oxidative stress, leading to damage in the spore cell structure.