Recipient Organization
CONNECTICUT AGRICULTURAL EXPERIMENT STATION
PO BOX 1106
NEW HAVEN,CT 06504
Performing Department
(N/A)
Non Technical Summary
Nanoparticles (NPs) of nutrients have demonstrated strong promise in plant growth and productivity promotion. However, inefficient use due to run-off and the risk of the NP residuals in plant edible tissues restrict the broader application of nano-enabled agriculture, but both can be modulated by rational NP modifications that alter their retention on the leaf surface and interior penetration into the plants. The proposed work combines nanotechnology, plant sciences, and analytical chemistry to understand the underlying mechanisms of NP-leaf surface interactions (surface retention and penetration) as a function of NP surface modification and morphology. We hypothesize that appropriate modifications on NP surfaces and exploiting NP morphological differences will enable achieving stable leaf retention and controlled penetration broadly applicable to a suite of NPs. This will provide information on the design, synthesis, and modification of various agriculturally relevant NPs for specific nutrient delivery goals.
Animal Health Component
(N/A)
Research Effort Categories
Basic
80%
Applied
(N/A)
Developmental
20%
Goals / Objectives
Nanoparticles (NPs) of nutrients demonstrate strong promise in plant growth promotion andsuppression of environmental stresses, leading to higher productivity. However, inefficient use due to run-off and the risk of the NP residuals in plant edible tissues restrict the broader application of nano-enabled agriculture, but both can be modulated by rational NP modifications that alter their leaf surface retention and plant interior penetration. We are proposing to reduce the agrochemical run-off, thus reducing the input ratewith two objectives that will enable controlled penetration and improved leaf retention. We aim to develop modified NPs with surface coatings and morphology optimization to1)keep them tightly adhered to the leaf surface with less run-off, and2)controlpenetration into the plant tissue as needed for different application scenarios. More specifically, with longer retention time and better contact angle on the leaves,formulations that allow NPs to adhere tightly to the leaf surface, but with less penetration into the plant tissue, will be used to supply dissolved nutrients for plant growth enhancement and postharvest fruit protection; In the meantime, those formulations that induced greater intact NP penetration will be used as nano-carriers to deliver pesticides or genetic materials. We are also aiming to establish a useful database to provide information on the design, synthesis, and modification of various agro-NPs for researchers, and rational choice of NP formulations, when needed for specific crop production systems. Specifically, our objectives are:Objective 1: Evaluate the effect of surface coating on the fate of NPson/in representative model plants (having different content of leaf wax).Objective 2: Evaluate the effect of particle morphology on NP fate on/inrepresentative model plants.
Project Methods
Approach for Objective 1:Modification of NPs:Zn and Cu-based NPs will be synthesized and surface-modified.Plant model selection:Waxy surface with hydrophobicity represents the leaf surfaces of most of the global crop plants. Lettuce (Lactuca sativa) and tomato (Solanum lycopersicum)will be used as model species.Treatment design:Plants will be grown under greenhouse conditions following standard protocols used at CAES. We will apply suspensions of NPs with different modified surfaces to plant leaves (lettuce andtomato) and fruit (tomato) to assess surface properties and morphology attributes at 50 and 200 mg/L of the NPs.Hydrophobicity and leaf contact efficiencywill be measured by contact angle. The correlation of surface hydrophobicity with treatment time and concentration will be investigated.Zeta-potential and particle size distributionwill be measured by Malvern Zetasizer Nano ZS-90 following a laser doppler electrophoresis procedure. NPs morphologywill be characterized using SEM and TEM.Surface bio-transformationsof NPs will be assessed by XPS.Transpiration and photosynthesiswill be measured weekly during exposure using a PhotosynQ system.Nitrogen and protein contentwill be quantified on a Leco Nitrogen Determinator (Model FP828).Oxidative stress assays: Lipid peroxidation as indicated by malondialdehyde (MDA) formation, total ROS, superoxide dismutase, catalase, peroxidase, glutathione reductase, and ascorbate peroxidase levels will be determined by standard techniques.Visualization and localization of NPs within plant tissueswill be performed using Enhanced Darkfield Hyperspectral Microscopy (EDHM) and Two-Photon Microscopy.Quantification of NPs within different plant tissueswill be conducted using inductively coupled plasma optical emission spectroscopy (ICP-OES) (iCAP 6500, Thermo Fisher Scientific, Waltham, MA) after acid digestion. The isolation of the surface-attached fraction, cuticle fraction, and leaf tissue fraction will be conducted.Quantification of NPs dissolution and leaf retentionwill be performed using ICP-OES as described above. Active ingredient release from modified NPs will be evaluated in DI water.Approach for Objective 2: Preparation of NPs with different morphologies:Quantum dots, wafers, wires, and sheets of different sizes will be synthesized. Differently shaped NPs of the same chemistry will be purchased from commercial sources (US Research Nanomaterials, Inc. and American Elements®).Treatment design:Suspensions of NPs selected from Objective 1 will be prepared in DI water at 50 and 200 mg/L for foliar exposure (leaf and fruit). The experimental procedure will be the same as described in Objective 1, but using differently modified NPs. Also, the same endpoints will be measured, and in addition:Plant synthetic biological molecular analysis: Quantitative PCR (qPCR) will be performed in a StepOne™ Real-Time PCR system according to the manufacturer's instructions. The metabolomicanalysiswill be conducted using LC-MS/MS.