The impact of nanosize was evaluated by comparing of the transcriptomic response of Arabidopsis thaliana roots to ZnO nanoparticles (nZnO), bulk ZnO, and ionic Zn(2+). Microarray analyses revealed 416 up- and 961 down-regulated transcripts (expression difference >2-fold, p [FDR] < 0.01) after a seven-day treatment with nZnO (average particle size 20 nm, concentration 4 mg L(-1)). Exposure to bulk ZnO resulted in 816 up- and 2179 down-regulated transcripts. The most dramatic changes (1711 transcripts up- and 3242 down-regulated) were caused by the presence of ionic Zn(2+) (applied as ZnSO4.7H20 at a concentration of 14.14 mg L(-1), corresponding to the amount of Zn contained in 4 mg L(-1) ZnO). Genes involved in stress response (e.g., to salt, osmotic stress or water deprivation) were the most relatively abundant group of gene transcripts up-regulated by all three Zn treatments while genes involved in cell organization and biogenesis (e.g., tubulins, arabinogalactan proteins) and DNA or RNA metabolism (e.g., histones) were the most relatively abundant groups of down-regulated transcripts. The similarity of the transcription profiles and the increasing number of changed transcripts correlating with the increased concentration of Zn(2+) in cultivation medium indicated that released Zn(2+) may substantially contribute to the toxic effect of nZnO because particle size has not demonstrated a decisive role.

• MeSH
• Arabidopsis účinky léků   genetika   MeSH
• kationty dvojmocné MeSH
• kořeny rostlin účinky léků   genetika   MeSH
• nanočástice chemie   toxicita   MeSH
• oxid zinečnatý chemie   farmakologie   toxicita   MeSH
• síran zinečnatý chemie   toxicita   MeSH
• stanovení celkové genové exprese metody   MeSH
• testy toxicity MeSH
• velikost částic MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• srovnávací studie MeSH

The essential requirement for the effective phytoremediation is selection of a plant species which should be metal tolerant, with high biomass production and known agronomic techniques. The above mentioned criteria are met by crop plant sorghum (Sorghum bicolor). The response of hydroponically grown S. bicolor plants to cadmium and zinc stress was followed. The impact of metal application on physiological parameters, including changes in chlorophylls contents and antioxidative enzymes activities, was followed during the stress progression. Cadmium and zinc were accumulated primarily in the roots of sorghum plants. However, elevation of metal concentrations in the media promoted their transfer to the shoots. Toxic effects of metals applied at lower concentrations were less serious in the shoots in comparison with their influence to the roots. When applied at higher concentrations, transfer of the metals into the leaves increased, causing growth reduction and leading to Chl loss and metal-induced chlorosis. Moreover, higher metal levels in the roots overcame the quenching capacity of peroxidase and glutathione transferase, which was associated with reduction of their activities. Fortification of antioxidant system by addition of glutathione significantly increased the accumulation of cadmium in the roots as well as in the shoots at the highest cadmium concentration applied.

• MeSH
• biodegradace MeSH
• biomasa MeSH
• glutathion metabolismus   MeSH
• kadmium metabolismus   toxicita   MeSH
• kořeny rostlin enzymologie   růst a vývoj   metabolismus   MeSH
• listy rostlin enzymologie   růst a vývoj   metabolismus   MeSH
• peroxidasy metabolismus   MeSH
• Sorghum enzymologie   růst a vývoj   metabolismus   MeSH
• zinek metabolismus   toxicita   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH