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1.
Environ Sci Technol ; 53(20): 11714-11724, 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31509697

RESUMO

Increasing CO2 levels are speculated to change the effects of engineered nanomaterials in soil and on plant growth. How plants will respond to a combination of elevated CO2 and nanomaterials stress has rarely been investigated, and the underlying mechanism remains largely unknown. Here, we conducted a field experiment to investigate the rice (Oryza sativa L. cv. IIyou) response to TiO2 nanoparticles (nano-TiO2, 0 and 200 mg kg-1) using a free-air CO2 enrichment system with different CO2 levels (ambient ∼370 µmol mol-1 and elevated ∼570 µmol mol-1). The results showed that elevated CO2 or nano-TiO2 alone did not significantly affect rice chlorophyll content and antioxidant enzyme activities. However, in the presence of nano-TiO2, elevated CO2 significantly enhanced the rice height, shoot biomass, and panicle biomass (by 9.4%, 12.8%, and 15.8%, respectively). Furthermore, the Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis revealed that genes involved in photosynthesis were up-regulated while most genes associated with secondary metabolite biosynthesis were down-regulated in combination-treated rice. This indicated that elevated CO2 and nano-TiO2 might stimulate rice growth by adjusting resource allocation between photosynthesis and metabolism. This study provides novel insights into rice responses to increasing contamination under climate change.


Assuntos
Nanopartículas , Oryza , Dióxido de Carbono , Nitrogênio , Fotossíntese , Transcriptoma
2.
Environ Toxicol Chem ; 27(4): 970-7, 2008 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-18333686

RESUMO

Chemical analyses and biological measurements were investigated in leaves of Vicia faba seedlings exposed to extraneous lead (Pb) at 0 to 2,000 mg/kg of soil for a month. The results showed that superoxide radical (O*(2)(-)) production, increased along with total Pb in leaves and available Pb in soil, resulted in enhancement of malondialdehyde and carbonyl groups. Antioxidant enzymes, including corresponding isoenzymes and heat shock protein 70 (hsp 70), were also enhanced to some extent. Significant changes were detected in the patterns and intensities of guaiacol peroxidase isoenzymes, while superoxide dismutase, catalase, and ascorbate peroxidase isoenzymes only changed intensities. Superoxide dismutase activities increased with the increase of extraneous Pb at 0 to 500 mg/kg of soil and tended to decline thereafter, which might be responsible for the decrease of hydrogen peroxide and accumulation of O*(2)(-). Guaiacol peroxidase and ascorbate peroxidase enzymes were upregulated to become major scavengers of excess hydrogen peroxide on the condition of decreased catalase activities. Levels of hsp 70 were well correlated with Pb contents in leaves (r=0.777), O*(2)(-) accumulation (r = 0.985, p<0.01), and carbonyl groups (r=0.920, p<0.01) under extraneous Pb at 0 to 250 mg/kg of soil, suggesting that hsp 70 induced by O*(2)(-) was possibly involved in disposal of denatured proteins. The results showed that O*(2)(-), hsp 70, and guaiacol peroxidase isoenzymes had the most sensitive responses in the seedlings and these parameters could be potential early biomarkers of soil Pb contamination.


Assuntos
Chumbo/toxicidade , Estresse Oxidativo , Plântula/efeitos dos fármacos , Poluentes do Solo/toxicidade , Vicia faba/efeitos dos fármacos , Ascorbato Peroxidases , Biomarcadores , Catalase/metabolismo , Proteínas de Choque Térmico HSP70/análise , Peroxidação de Lipídeos/efeitos dos fármacos , Peroxidases/metabolismo , Plântula/metabolismo , Superóxido Dismutase/metabolismo , Vicia faba/metabolismo
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