Determining the Size Exclusion for Nanoparticles in Citrus Leaves

Abstract

<jats:p>Implementation of nanotechnology in agriculture is intimately dependent on the capacity of nanoparticles (NPs) to move within the plant body and reach the targeted cells. Although the fibrillar nature of the plant cell wall permits the movement of molecules through its porous matrix (apoplast), the movement of particles through the aqueous apoplastic milieu has its size limitations given the tightly knitted cellulose/hemicellulose fiber structure. In the present study, we used fluorescent NPs of different composition and sizes, and followed their movement into citrus leaves by fluorescent microscopy. Our results indicate that in citrus leaves, the size exclusion limit for NPs is of ≈5.4 nm. This conclusion was based on the capacity of PAMAM dendrimers G-4 and G-5 (4.5 and 5.4 nm, respectively) to move through the cell wall and into the phloem, but failure of similar PAMAM dendrimers G-6 (6.7 nm) to move through the apoplast. Dendrimer NPs 5.4 nm and smaller were observed to penetrate the leaf tissue, and then taken up and mobilized by the phloem elements. The current study provides evidence on the size limit for NPs use in agriculture.</jats:p>

Dual Effect of Nanomaterials on Germination and Seedling Growth: Stimulation vs. Phytotoxicity

“…This process can slow down the uptake rate of active ingredients by plant roots, improve compounds stability, reduce the wastes produced, reduce their applied amount, and reduce costs [ 157 , 158 ]. Etxeberria et al [ 159 ] used fluorescent NPs of different composition and sizes and followed their movement into citrus leaves by fluorescent microscopy. Their results indicate that in citrus leaves, the size exclusion limit for NPs is of 5.4 nm.…”

Adsorption of nanoparticles suspended in a drop on a leaf surface of Perilla frutescens and their infiltration through stomatal pathway

“…6 a). Apoplastic transport (transport in the intercellular space between cells) and symplastic transport (endocytosis and translocation in phloem vessels) have different size exclusion limits 48 . A previous study reported that the route for cellular translocation is influenced by the size of NPs 49 .…”

Physiological regulation of bud burst in grapevine

“…In hair cells of Raphanus sativus roots and fibres of Gossypium hirsutum , the pore size was as small as 3.5 to 3.8 nm, while in the parenchyma cells of the leaves of Xanthium strumarium and Commelina communis they were determined to be between 4.5 to 5.2 nm (Carpita et al , 1979). In citrus leaves, the size exclusion limits to move through the cell wall and into the phloem was estimated to be between 4.5 to 5.4 nm (Etxeberria et al , 2016). These values are much higher than the 2.1 nm diameter pore determined here in buds, suggesting that quiescent perennials buds are quite well-isolated.…”