Mechanisms of Influence of Size and Surface Charge on the Bioaccumulation of Nanoparticles in Plants
Zeynab Mikayilzada1 
, Vafa Ramazanli2*
Abstract. Objective: This study aims to investigate the influence of nanoparticle size and surface charge on their uptake, translocation, and bioaccumulation in plants and to identify the underlying mechanisms governing these processes. Methods: A comprehensive analysis of recent experimental studies on plant–nanoparticle interactions was conducted, focusing on the effects of nanoparticle physicochemical properties on plant uptake pathways and accumulation patterns. Results: The findings demonstrate that smaller nanoparticles exhibit higher mobility and greater penetration through plant cell walls and membranes, resulting in enhanced translocation to aerial tissues. In contrast, larger nanoparticles predominantly accumulate on root surfaces, limiting their internal transport. Surface charge was also found to significantly affect bioaccumulation. Positively charged nanoparticles showed stronger interactions with negatively charged plant cell wall components, leading to increased adsorption and uptake, whereas negatively charged or neutral nanoparticles exhibited lower uptake efficiency. Nanoparticles entered plant tissues through apoplastic and symplastic pathways, with endocytosis and ion channel-mediated transport contributing to cellular internalization. Accumulated nanoparticles were associated with oxidative stress, altered nutrient transport, and changes in gene expression. Conclusion: Nanoparticle size and surface charge are key determinants of bioaccumulation in plants. Understanding their role in uptake and translocation mechanisms is essential for ecological risk assessment and the development of safer nanomaterials for agricultural and environmental applications.
Keywords: nanoparticles, bioaccumulation, plants, particle size, surface charge, uptake mechanisms, phytotoxicity