The Effect of Silver and Copper Nanoparticles on the Condition of English Oak (Quercus robur L.) Seedlings in a Container Nursery Experiment

Jacek Olchowik,Marta Aleksandrowicz-Trzcińska,Roman Bzdyk,Marcin Studnicki,Magdalena Bederska-Błaszczyk,Alexander Urban

doi:10.3390/f8090310

Jacek Olchowik, Marta Aleksandrowicz-Trzcińska + Show 4 more

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https://doi.org/10.3390/f8090310

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Abstract

Some studies indicate that metal nanoparticles can be used in plant cultivation as fungicides and growth stimulators. The aim of this study was to evaluate the effect of silver (AgNPs) and copper nanoparticles (CuNPs) on the growth parameters, on the extent of leaves infected by powdery mildew and on spontaneous ectomycorrhizal colonization of English oak (Quercus robur L.) seedlings growing in containers. Nanoparticles were applied to foliage four times during one vegetation season, at four concentrations: 0, 5, 25 and 50 ppm. The adsorption of NPs to leaves was observed by microscopical imaging (TEM). The tested concentrations of AgNPs and CuNPs did not have any significant effect on the growth parameters of the oak seedlings. TEM results showed disturbances in the shape of plastids, plastoglobules and the starch content of oak leaves treated with 50 ppm Cu- and AgNPs, while no changes in the ultrastructure of stems and roots of oak plants treated with NPs were observed. No significant difference in powdery mildew disease intensity was observed after NP foliar app lication. Four ectomycorrhizal taxa were detected on oak roots (Sphaerosporella brunnea, Thelephora terrestris, Paxillus involutus and Laccaria proxima). Oak seedlings treated (foliar) with CuNPs and AgNPs at 25 ppm were characterised by the highest degree of mycorrhization (respectively, 37.1% and 37.5%) among all treatments including the control treatment. None of the tested NPs manifested phytotoxicity in the examined Q. robur seedlings under container nursery conditions.

Highlights

Nanoparticles are atomic or molecular aggregates with dimensions between 1 nm and 100 nm [1,2]
Plants as primary producers with huge absorbing surfaces may play a key role as a potential gateway for NPs into the food webs
The question as to which extent mutualistic symbionts such as ectomycorrhizal fungi are affected by the application of nanoparticles is still a research gap

Summary

Introduction

Nanoparticles (nano-scale particles, NP) are atomic or molecular aggregates with dimensions between 1 nm and 100 nm [1,2]. Program in forest nursery production in Poland, trials are carried out to use non-conventional plant protection methods [4]. Alternative methods are being sought, in forestry, which may offer phytosanitary protection and growth improvement with minimal impact on the environment. Plants as primary producers with huge absorbing surfaces may play a key role as a potential gateway for NPs into the food webs. Nanoparticles can affect plant growth directly or indirectly, through effects on the plants’ microbial associates. Growth effects are often considered as the result of the antimicrobial properties of nanoparticles [6]. The question as to which extent mutualistic symbionts such as ectomycorrhizal fungi are affected by the application of nanoparticles is still a research gap

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