Uptake and Translocation of a Silica Nanocarrier and an Encapsulated Organic Pesticide Following Foliar Application in Tomato Plants

Abstract

Pesticide nanoencapsulation and its foliar application are promising approaches for improving the efficiency of current pesticide application practices, whose losses can reach 99%. Here, we investigated the uptake and translocation of azoxystrobin, a systemic pesticide, encapsulated within porous hollow silica nanoparticles (PHSNs) of a mean diameter of 253 ± 73 nm, following foliar application on tomato plants. The PHSNs had 67% loading efficiency for azoxystrobin and enabled its controlled release over several days. Thus, the nanoencapsulated pesticide was taken up and distributed more slowly than the nonencapsulated pesticide. A total of 8.7 ± 1.3 μg of the azoxystrobin was quantified in different plant parts, 4 days after 20 μg of nanoencapsulated pesticide application on a single leaf of each plant. In parallel, the uptake and translocation of the PHSNs (as total Si and particulate SiO2) in the plant were characterized. The total Si translocated after 4 days was 15.5 ± 1.6 μg, and the uptake rate and translocation patterns for PHSNs were different from their pesticide load. Notably, PHSNs were translocated throughout the plant, although they were much larger than known size-exclusion limits (reportedly below 50 nm) in plant tissues, which points to knowledge gaps in the translocation mechanisms of nanoparticles in plants. The translocation patterns of azoxystrobin vary significantly following foliar uptake of the nanosilica-encapsulated and nonencapsulated pesticide formulations.

Mobility of oxathiapiprolin in and between tomato plants

“…The fungicide azoxystrobin was reported to translocate in 2 days from a leaflet of tomato to other parts of the plant: 19% to stem, 10% to youngest leaves, 4% to mature leaves and 2% to the root 23 . When [ 14 C]cymoxanil (anti‐oomycete fungicide) was applied to the root of potted tomato plants, 75% and 90% of the label reached the shoot in 1 and 16 h respectively, but when applied to a leaf only 5% of the label reached the other parts of the plant 24 .…”

“…22 The fungicide azoxystrobin was reported to translocate in 2 days from a leaflet of tomato to other parts of the plant: 19% to stem, 10% to youngest leaves, 4% to mature leaves and 2% to the root. 23 When [ 14 C]cymoxanil (anti-oomycete fungicide) was applied to the root of potted tomato plants, 75% and 90% of the label reached the shoot in 1 and 16 h respectively, but when applied to a leaf only 5% of the label reached the other parts of the plant. 24 The non-systemic fungicide fludioxonil was recently reported 25 to control Fusarium T4 in banana by foliar spray of fludioxonil-loaded glycine methyl ester-conjugated polysuccinimide nanoparticles (PGA) nanoparticles (FLU@PGA).…”

Application of ZnO Nanoparticles Encapsulated in Mesoporous Silica on the Abaxial Side of a Solanum lycopersicum Leaf Enhances Zn Uptake and Translocation via the Phloem

“…Plants were sampled sacrificially 2 and 5 days after foliar application of NPs and their dry weights were comparable between the two treatments ( p > 0.05, t test, Table S1). Two and 5 days were selected as sampling times as this provided the appropriate time bracket to demonstrate particle uptake, translocation and dissolution processes in the plant, and 5 days was required to reach sufficient concentrations of Si in the petiole for mass spectrometry imaging. ,, For each treatment, a total of nine plant replicates were maintained. To measure the total Zn and Si concentrations (with ICP-OES) and particle size distribution in different plant parts (spICP-MS), triplicate samples were measured.…”

“…Mesoporous silica NPs (MSNs) have been proposed as an efficient vehicle for the delivery of chemicals to plants, because upon their uptake plants may slowly dissolve and assimilate Si into their structural tissues enhancing stalk rigidity, disease resistance, and crop yield, − and as well because of their high biocompatibility, and controlled-release properties. − Our prior study showed that the addition of a mesoporous silica shell enabled significant uptake and translocation of ZnO NPs in tomato plants following foliar application, whereas uptake of bare ZnO NPs was negligible . Compared to the foliar application with conventional Zn 2+ (supplied as a ZnCl 2 solution), ZnO@MSN did not result in the scorching of a leaf that was caused by ZnCl 2 , a hygroscopic salt.…”

Charge, Aspect Ratio, and Plant Species Affect Uptake Efficiency and Translocation of Polymeric Agrochemical Nanocarriers

“…Star polymer based nanocarriers with different sizes, charges, and hydrophobicity also had high (∼100%) uptake and up to ∼30% total translocation away from the leaf after foliar exposure . Approximately 100 nm polypeptide nanoparticles and polymer functionalized carbon nanotubes have delivered nucleic acids into specific cell organelles such as the cell nucleus and chloroplasts to transfect plants after foliar application. ,− Mesoporous silica nanoparticles have delivered micronutrients and active ingredients into tomato plants with significant (∼20%) phloem loading and translocation. , These studies all indicate that foliar applied nanomaterials can pass through physical barriers in plants and potentially achieve higher agent delivery efficiency compared to conventional agrochemical application techniques …”