Nanomaterials and Foliar Uptake Mechanisms in Plants

Advances in nanotechnology have enabled the design of foliar sprays containing engineered nanomaterials that can traverse leaf surfaces and deliver nutrients, pesticides or regulatory compounds with enhanced precision. Leaf uptake proceeds via penetration through the waxy cuticle, entry via stomatal pores or interaction with surface appendages such as trichomes. Once inside, nanoscale particles may follow apoplastic pathways through cell walls or enter the symplast and redistribute via vascular tissues. Key material parameters—including particle size, shape (aspect ratio), surface charge and chemical composition—govern residence on the leaf, penetration efficiency, cellular internalisation and long-distance translocation in xylem and phloem. Understanding these mechanisms offers routes to reduce application rates, limit off-target effects and improve sustainability of crop protection and biofortification strategies at the global scale.

Research from Nature Portfolio

Polymeric nanoparticles with precisely tuned size and surface functionality have been shown to breach the plant cell‐wall barrier and access internal tissues, despite the presence of a rigid cuticle. Studies using well-defined block copolymer particles reveal that neutral particles penetrate rapidly into root and leaf cells, while anionic particles are gradually loaded into the xylem for upward transport. Positively charged nanoparticles largely adhere to the outer epidermis and exhibit limited systemic movement. Such findings demonstrate that particle charge and size inversely correlate with uptake efficiency and highlight design rules for delivering agrochemicals directly to target tissues.

Investigations into particulate matter deposition on leaf surfaces have employed gold‐nanoparticle-laden droplets to mimic environmental ultrafine pollutants. Detailed imaging of Perilla frutescens leaves shows that evaporation-driven convective flow within sessile drops concentrates particles at stomatal openings, facilitating their entry into the leaf interior. Three-dimensional fluorescence and X-ray microscopy capture nanoparticle infiltration through open stomata and distribution in mesophyll layers, clarifying the physical dynamics that govern foliar uptake of colloidal species.

Nanomaterials and Foliar Uptake Mechanisms in Plants publication trend

The graph below shows the total number of articles in nanomaterials and foliar uptake mechanisms in plants across all publications each year (not limited to Nature Index journals).

Technical terms

Nanomaterial: A material engineered at dimensions of roughly 1–100 nm, exhibiting unique physical and chemical properties.

Foliar uptake: Absorption of substances through the leaf surface into internal plant tissues.

Stomatal pathway: Entry route for gases or particles via adjustable leaf pores (stomata) that regulate gas exchange.

Apoplastic transport: Movement of solutes or particles through cell walls and intercellular spaces without crossing plasma membranes.

Phloem transport: Long-distance movement of photoassimilates or solutes through sieve tubes driven by pressure gradients.

Aspect ratio: The ratio of particle length to width, influencing passage through narrow biological conduits.

Surface charge: Electrical potential at the particle interface, affecting adhesion to cuticle and interactions with cell membranes.

Cuticle: A waxy, hydrophobic layer on the leaf surface that serves as the first barrier to uptake.

References

1. Polymer nanoparticles pass the plant interface. Nature Communications (2022).
2. Charge, Aspect Ratio, and Plant Species Affect Uptake Efficiency and Translocation of Polymeric Agrochemical Nanocarriers. Environmental Science and Technology (2023).
3. Adsorption of nanoparticles suspended in a drop on a leaf surface of Perilla frutescens and their infiltration through stomatal pathway. Scientific Reports (2021).
4. Nanoparticles in Plants: Uptake, Transport and Physiological Activity in Leaf and Root. Materials (2023).
5. Penetration of foliar-applied Zn and its impact on apple plant nutrition status: in vivo evaluation by synchrotron-based X-ray fluorescence microscopy. Horticulture Research (2020).