The Ef fects of Polyethyleneimine Coating of Gold Nanoparticles on Photosynthesis and Growth of the Moss Physcomitrium patens

Abstract

 The widespread use of gold nanoparticles (Au-NP) as nanocarriers has led to several studies in animal cells to evaluate their cytotoxic ef fects. In contrast, little is known about the impact of gold nanoparticles on photosynthesis and plant growth. In this work, we present a study on the physiological and morphological responses of bryophytes to Au-NPs prepared with dif ferent contents of polyethyleneimine (PEI) using Physcomitrium patens (P. patens) as a model system. Results are presented where Au-NPs without PEI induce the generation of larger gametophores. On the other hand, Au-NPs with a high concentration of PEI were found to be phytotoxic. In contrast, Au/PEI-NPs with a medium PEI concentration cause early stress, but plant cells can recover growth, greening and photosynthetic activity under these conditions. Finally, low concentrations of Au/PEI-NPs do not cause adverse ef fects on P. patens in terms of growth, gametophyte development, and photosystem II maximum quantum yield. Toxicity was closely related to the content of PEI. This study reveals for the first time the ef fects of Au-NPs and Au/PEI-NPs on bryophytes at dif ferent growth stages.