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Single Walled Carbon Nanotubes Exhibit Dual-Phase Regulation to Exposed Arabidopsis Mesophyll Cells

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ABSTRACT

Herein we are the first to report that single-walled carbon nanotubes (SWCNTs) exhibit dual-phase regulation to Arabidopsis mesophyll cells exposed to different concentration of SWCNTs. The mesophyll protoplasts were prepared by enzyme digestion, and incubated with 15, 25, 50, 100 μg/ml SWCNTs for 48 h, and then were observed by optical microscopy and transmission electron microscopy, the reactive oxygen species (ROS) generation was measured. Partial protoplasts were stained with propidium iodide and 4'-6- diamidino-2-phenylindole, partial protoplasts were incubated with fluorescein isothiocyanate-labeled SWCNTs, and observed by fluorescence microscopy. Results showed that SWCNTs could traverse both the plant cell wall and cell membrane, with less than or equal to 50 μg/ml in the culture medium, SWCNTs stimulated plant cells to grow out trichome clusters on their surface, with more than 50 μg/ml SWCNTs in the culture medium, SWCNTs exhibited obvious toxic effects to the protoplasts such as increasing generation of ROS, inducing changes of protoplast morphology, changing green leaves into yellow, and inducing protoplast cells' necrosis and apoptosis. In conclusion, single walled carbon nanotubes can get through Arabidopsis mesophyll cell wall and membrane, and exhibit dose-dependent dual-phase regulation to Arabidopsis mesophyll protoplasts such as low dose stimulating cell growth, and high dose inducing cells' ROS generation, necrosis or apoptosis.

No MeSH data available.


TEM images of protoplasts. a The chloroplasts in normal protoplasts; e the chloroplasts of protoplasts treated with SWCNTs; b fluffy chloroplasts in control protoplasts; f fluffy chloroplasts in the protoplasts treated with SWCNTs; c the part structure of normal protoplasts; g the part structure of protoplasts treated with SWCNTs; d the filament structure in the chloroplasts; h the loosen filament structure in the chloroplasts in protoplasts treated with SWCNTs, all arrows indicated the location of SWCNTs.
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Figure 5: TEM images of protoplasts. a The chloroplasts in normal protoplasts; e the chloroplasts of protoplasts treated with SWCNTs; b fluffy chloroplasts in control protoplasts; f fluffy chloroplasts in the protoplasts treated with SWCNTs; c the part structure of normal protoplasts; g the part structure of protoplasts treated with SWCNTs; d the filament structure in the chloroplasts; h the loosen filament structure in the chloroplasts in protoplasts treated with SWCNTs, all arrows indicated the location of SWCNTs.

Mentions: We also observed the morphological changes of chloroplasts in protoplasts incubated with SWCNTs for 48 h. As shown in Figure 5e–h, SWCNTs could enter into chloroplasts, and caused the chloroplasts looseness of structure, which was very obvious in Figure 5h.


Single Walled Carbon Nanotubes Exhibit Dual-Phase Regulation to Exposed Arabidopsis Mesophyll Cells
TEM images of protoplasts. a The chloroplasts in normal protoplasts; e the chloroplasts of protoplasts treated with SWCNTs; b fluffy chloroplasts in control protoplasts; f fluffy chloroplasts in the protoplasts treated with SWCNTs; c the part structure of normal protoplasts; g the part structure of protoplasts treated with SWCNTs; d the filament structure in the chloroplasts; h the loosen filament structure in the chloroplasts in protoplasts treated with SWCNTs, all arrows indicated the location of SWCNTs.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211858&req=5

Figure 5: TEM images of protoplasts. a The chloroplasts in normal protoplasts; e the chloroplasts of protoplasts treated with SWCNTs; b fluffy chloroplasts in control protoplasts; f fluffy chloroplasts in the protoplasts treated with SWCNTs; c the part structure of normal protoplasts; g the part structure of protoplasts treated with SWCNTs; d the filament structure in the chloroplasts; h the loosen filament structure in the chloroplasts in protoplasts treated with SWCNTs, all arrows indicated the location of SWCNTs.
Mentions: We also observed the morphological changes of chloroplasts in protoplasts incubated with SWCNTs for 48 h. As shown in Figure 5e–h, SWCNTs could enter into chloroplasts, and caused the chloroplasts looseness of structure, which was very obvious in Figure 5h.

View Article: PubMed Central - HTML - PubMed

ABSTRACT

Herein we are the first to report that single-walled carbon nanotubes (SWCNTs) exhibit dual-phase regulation to Arabidopsis mesophyll cells exposed to different concentration of SWCNTs. The mesophyll protoplasts were prepared by enzyme digestion, and incubated with 15, 25, 50, 100 μg/ml SWCNTs for 48 h, and then were observed by optical microscopy and transmission electron microscopy, the reactive oxygen species (ROS) generation was measured. Partial protoplasts were stained with propidium iodide and 4'-6- diamidino-2-phenylindole, partial protoplasts were incubated with fluorescein isothiocyanate-labeled SWCNTs, and observed by fluorescence microscopy. Results showed that SWCNTs could traverse both the plant cell wall and cell membrane, with less than or equal to 50 μg/ml in the culture medium, SWCNTs stimulated plant cells to grow out trichome clusters on their surface, with more than 50 μg/ml SWCNTs in the culture medium, SWCNTs exhibited obvious toxic effects to the protoplasts such as increasing generation of ROS, inducing changes of protoplast morphology, changing green leaves into yellow, and inducing protoplast cells' necrosis and apoptosis. In conclusion, single walled carbon nanotubes can get through Arabidopsis mesophyll cell wall and membrane, and exhibit dose-dependent dual-phase regulation to Arabidopsis mesophyll protoplasts such as low dose stimulating cell growth, and high dose inducing cells' ROS generation, necrosis or apoptosis.

No MeSH data available.