Discerning the mechanism of the multiwalled carbon nanotubes effect on root cell water and nutrient transport

Abstract

Multiwalled carbon nanotubes (MWCNTs) are tubular carbon structures that are able to enter cells through holes in the plasma membrane and produce changes in gene expression. In this work, we compared the functionality of carbon nanotubes with the electroporation that perforates membranes, in Brassica oleracea var. Italica (broccoli) root protoplasts. For this, we combined those treatments with control conditions and abiotic stress (salinity) in order to elucidate if the response is related to conditions optimal for the plant. The measurement of the osmotic water permeability (Pf), mineral concentrations and expression levels of aquaporins (PIP1s and PIP2s) revealed that the physiological action of the nanotubes was similar to that achieved with electroporation for both Pf and the concentrations of nutrients in the protoplasts. On the other hand, PIP1s and PIP2s expression was increased in the protoplasts receiving the control plus MWCNTs treatment but not in those treated with electroporation. This opens new and interesting lines, as it shows that nanotubes are able to modulate the expression of aquaporins.

Keywords: Aquaporins; Mineral nutrients; Multiwalled carbon nanotubes; Osmotic water permeability; PIP1; PIP2; Protoplasts.