The small size of nanoparticles (NPs), with dimensions between 1 and 100 nm, results in unique chemical and physical characteristics, which is why they are implemented in various consumer products. Therefore, an important concern is the potential detrimental impact of NPs on the environment. As plants are a vital part of ecosystem, investigation of the phytotoxic effects of NPs is particularly interesting. This study investigated the potential phytotoxicity of silver nanoparticles (AgNPs) on tobacco (Nicotiana tabacum) plants and compared it with the effects of the same AgNO concentrations. Accumulation of silver in roots and leaves was equally efficient after both AgNP and AgNO treatment, with predominant Ag levels found in the roots. Exposure to AgNPs did not result in elevated values of oxidative stress parameters either in roots or in leaves, while AgNO induced oxidative stress in both plant tissues. In the presence of both AgNPs and AgNO, root meristem cells became highly vacuolated, which indicates that vacuoles might be the primary storage target for accumulated Ag. Direct AgNP uptake by root cells was confirmed. Leaf ultrastructural studies revealed changes mainly in the size of chloroplasts of AgNP-treated and AgNO-treated plants. All of these findings indicate that nano form of silver is less toxic to tobacco plants than silver ions.

Plants endure a variety of abiotic and biotic stresses, all of which cause major limitations to production. Among abiotic stressors, heavy metal contamination represents a global environmental problem endangering humans, animals, and plants. Exposure to heavy metals has been documented to induce changes in the expression of plant proteins. Proteins are macromolecules directly responsible for most biological processes in a living cell, while protein function is directly influenced by posttranslational modifications, which cannot be identified through genome studies. Therefore, it is necessary to conduct proteomic studies, which enable the elucidation of the presence and role of proteins under specific environmental conditions. This review attempts to present current knowledge on proteomic techniques developed with an aim to detect the response of plant to heavy metal stress. Significant contributions to a better understanding of the complex mechanisms of plant acclimation to metal stress are also discussed.

Acrylamide is a monomer widely used as an intermediate in the production of organic chemicals, e.g. polyacrylamides (PAMs). Since PAMs are low cost chemicals with applications in various industries and waste-and drinking water treatment, a certain amount of non-polymerised acrylamide is expected to end up in waterways. PAMs are non-toxic but acrylamide induces neurotoxic effects in humans and genotoxic, reproductive, and carcinogenic effects in laboratory animals. In order to evaluate the effect of acrylamide on freshwater organisms, bioassays were conducted on four species: algae Desmodesmus subspicatus and Pseudokirchneriella subcapitata, duckweed Lemna minor and water flea Daphnia magna according to ISO (International Organization for Standardisation) standardised methods. This approach ensures the evaluation of acrylamide toxicity on organisms with different levels of organisation and the comparability of results, and it examines the value of using a battery of low-cost standardised bioassays in the monitoring of pollution and contamination of aquatic ecosystems. These results showed that EC 50 values were lower for Desmodesmus subspicatus and Pseudokirchneriella subcapitata than for Daphnia magna and Lemna minor, which suggests an increased sensitivity of algae to acrylamide. According to the toxic unit approach, the values estimated by the Lemna minor and Daphnia magna bioassays, classify acrylamide as slightly toxic (TU=0-1; Class 1). The results obtained from algal bioassays (Desmodesmus subspicatus and Pseudokirchneriella subcapitata) revealed the toxic effect of acrylamide (TU=1-10; Class 2) on these organisms.