Zinc-functionalized thymol nanoemulsion for promoting soybean yield

Area of Science:

• Agricultural Science
• Nanotechnology
• Plant Pathology

Background:

• Soybean production faces challenges from bacterial diseases and suboptimal nutrient uptake.
• Thymol nanoemulsions show promise for agricultural applications, but zinc functionalization requires further investigation.
• Developing efficient delivery systems for plant protection and yield enhancement is crucial.

Purpose of the Study:

• To synthesize and characterize zinc-functionalized thymol nanoemulsion (Zn-TNE).
• To evaluate the effects of Zn-TNE on soybean seed physiology, plant defense mechanisms, and disease resistance.
• To assess the impact of Zn-TNE on soybean grain yield and explore its potential for micronutrient delivery.

Main Methods:

• Zinc-functionalized thymol nanoemulsion (Zn-TNE) was synthesized using a sonication method.
• Characterization involved Dynamic Light Scattering (DLS), High-Resolution Transmission Electron Microscopy (HR-TEM), Field Emission Scanning Electron Microscopy-Energy Dispersive Spectroscopy (FEG-SEM-EDS), Cryo-Field Emission Scanning Electron Microscopy (Cryo-FESEM), Fourier-Transform Infrared Spectroscopy (FTIR), and Atomic Absorption Spectroscopy (AAS).
• Seedling vigor, enzyme activities, chlorophyll content, reactive oxygen species levels, lignin deposition, disease control (bacterial pustule), and grain yield were assessed in soybean plants.

Main Results:

• Zn-TNE treatment improved seedling vigor and activities of seed-mobilizing enzymes (α-amylase, protease).
• Foliar application of Zn-TNE enhanced defense-antioxidant enzymes, balanced reactive oxygen species, increased chlorophyll content, and promoted lignin deposition in soybean plants.
• Field application of Zn-TNE significantly controlled bacterial pustule disease (28-79% reduction) and increased grain yield by up to 16.6% compared to bulk thymol and 50% compared to the control.

Conclusions:

• Zinc-functionalized thymol nanoemulsion (Zn-TNE) effectively enhances soybean plant defense, disease resistance, and grain yield.
• The observed benefits are attributed to Zn-TNE's ability to maintain cellular homeostasis and its diverse bioactivities.
• Zn-TNE presents a promising platform for the slow delivery of micronutrients to improve crop yield.