Foliar-applied silicon and zinc nanoparticles improve plant growth, biochemical attributes, and essential oil profile of fennel (Foeniculum vulgare Mill.) under different irrigation regimes

Hossein Mosaedi; hamid Mozafari; Behzad Sani; Abdollah Ghasemi Pirbalouti; Faezeh Rajabzadeh

Just Accepted

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Foliar-applied silicon and zinc nanoparticles improve plant growth, biochemical attributes, and essential oil profile of fennel (Foeniculum vulgare Mill.) under different irrigation regimes

Hossein Mosaedi, hamid Mozafari , Behzad Sani, Abdollah Ghasemi Pirbalouti, Faezeh Rajabzadeh

Abstract

The comparative efficacy of silicon (Si) and zinc (Zn) nanoparticles (NPs) in mitigating drought stress in fennel remains unexplored despite the widespread use of NPs for addressing environmental challenges in plants. Therefore, the present study was undertaken to evaluate the impact of Si and Zn NPs on enhancing plant growth and physiological-biochemical attributes of fennel under varying irrigation regimes. The two-year study was carried out in a spit-pot design with irrigation at three levels (100, 75, and 50% field capacity (FC)) and foliar application of Si and Zn NPs at five levels (control, Si at 1 and 2 mM, and Zn at 1 and 2 mM). The results showed that drought stress reduced plant performance. Increases in superoxide dismutase (SOD, 131%) and catalase (CAT, 276%) were seen after a 50% FC drought without the use of Si and Zn NPs. Conversely, biological yield (34%), seed yield (44%), Chl a+b (26%), relative water content (RWC, 21%), and essential oil (EO) yield (50%) were all reduced. However, the application of Zn and Si, particularly 1 mM Si and 2 mM Zn, greatly mitigated drought stress via lowering CAT and SOD activity and enhancing plant yield, Chl content, RWC, and EO. The composition of the EO consisted primarily of anethole, followed by limonene, fenchone, and estragole. During drought conditions, monoterpene hydrocarbons increased while oxygenated monoterpenes decreased. The opposite trend was observed for Si and Zn and Si NPs. The study suggests applying Zn at 2 mM followed by Si at 1 mM in improving plant resilience and EO yield in fennel plants under water stress conditions.

FP24149 Accepted 13 September 2024