Uptake and cellular distribution, in four plant species, of fluorescently labeled mesoporous silica nanoparticles

Abstract

We report the uptake of MSNs into the roots and their movement to the aerial parts of four plant species and their quantification using fluorescence, TEM and proton-induced x - ray emission (micro - PIXE) elemental analysis. Monodispersed mesoporous silica nanoparticles (MSNs) of optimal size and configuration were synthesized for uptake by plant organs, tissues and cells. These monodispersed nanoparticles have a size of 20 nm with interconnected pores with an approximate diameter of 2.58 nm. There were no negative effects of MSNs on seed germination or when transported to different organs of the four plant species tested in this study. Most importantly, for the first time, a combination of confocal laser scanning microscopy, transmission electron microscopy and proton-induced X-ray emission (micro-PIXE) elemental analysis allowed the location and quantification MSNs in tissues and in cellular and sub-cellular locations. Our results show that MSNs penetrated into the roots via symplastic and apoplastic pathways and then via the conducting tissues of the xylem to the aerial parts of the plants including the stems and leaves. The translocation and widescale distribution of MSNs in plants will enable them to be used as a new delivery means for the transport of different sized biomolecules into plants.

Interaction of Nanomaterials with Plants: What Do We Need for Real Applications in Agriculture?

“…Apoplastic transport takes place outside the plasma membrane through the extracellular spaces, cell walls of adjacent cells and xylem vessels (Sattelmacher, 2001), whereas symplastic transport involves movement of water and substances between the cytoplasm of adjacent cells through specialized structures called plasmodesmata (Roberts and Oparka, 2003) and sieve plates. The apoplastic pathway is important for radial movement within plant tissues, and allows nanomaterials to reach the root central cylinder and the vascular tissues, for further movement upwards the aerial part (González-Melendi et al, 2008;Larue et al, 2012;Zhao et al, 2012;Sun et al, 2014). Once inside the central cylinder, nanoparticles can move toward the aerial part though the xylem, following the transpiration stream (Cifuentes et al, 2010;Larue et al, 2012;Wang et al, 2012;Sun et al, 2014).…”

“…The apoplastic pathway is important for radial movement within plant tissues, and allows nanomaterials to reach the root central cylinder and the vascular tissues, for further movement upwards the aerial part (González-Melendi et al, 2008;Larue et al, 2012;Zhao et al, 2012;Sun et al, 2014). Once inside the central cylinder, nanoparticles can move toward the aerial part though the xylem, following the transpiration stream (Cifuentes et al, 2010;Larue et al, 2012;Wang et al, 2012;Sun et al, 2014). Nevertheless, reaching the xylem through the root implies crossing a barrier to the apoplastic pathway, the Casparian strip, which must be done following a symplastic way (Robards and Robb, 1972) via endodermal cells.…”

“…Nevertheless, reaching the xylem through the root implies crossing a barrier to the apoplastic pathway, the Casparian strip, which must be done following a symplastic way (Robards and Robb, 1972) via endodermal cells. Indeed, some nanomaterials can be stopped and accumulated at the Casparian strip (Larue et al, 2012;Sun et al, 2014;Lv et al, 2015). Another important symplastic transport is possible too, using the sieve tube elements in the phloem, and allowing distribution toward non-photosynthetic tissues and organs Raliya et al, 2016).…”

Application Of Nanotechnology In Agriculture And Food Industry, Its Prospects And Risks

“…Also amorphous SiO 2 NPs were highly effective against S. oryzae, causing more than 90% mortality [222]. Mesoporous SiO 2 NPs with a size of 20 nm and with interconnected pores with an approximate diameter of 3 nm did not have adverse effect on seed germination [185], indicating that SiO 2 -based NPs in any formulation could be applied as a safe pest control agent.…”

“…The release profiles of methomyl from methomyl-loaded shell cross-linked nanocapsules prepared by mixing azidobenzaldehyde and an aqueous solution of carboxymethyl chitosan nanocapsules in an aqueous solution at pH 6.0 were shown to be diffusion controlled, and the insecticidal activity of methomyl-loaded nanocapsules against the armyworm larvae was significantly superior to the original insecticide, and the relative control efficacy still maintained 100% over 7 days [185].…”