# Metformin as a novel organic foliar bio-stimulant to enhance peanut (Arachis hypogaea L.) growth and yield under drought stress conditions

## TL;DR

This study shows that applying Metformin to peanut plants under drought conditions improves growth, yield, and water efficiency.

## Contribution

Metformin is proposed as a novel, eco-friendly foliar bio-stimulant for enhancing peanut resilience under drought stress.

## Key findings

- Metformin at 7.5 mg L⁻¹ under 80% irrigation significantly increased plant height, biomass, and seed yield.
- Water use efficiency improved by 50.8% with Metformin treatment under 80% irrigation.
- Chlorophyll and carotenoid levels were highest with Metformin at 7.5 mg L⁻¹, indicating better photosynthesis.

## Abstract

Drought stress significantly affects peanut (Arachis hypogaea L.) growth and yield, necessitating strategies to enhance crop resilience. This study evaluates the impact of foliar-applied Metformin, gibberellic acid (GA₃), and indole-3-acetic acid (IAA) at concentrations of 5.0, 7.5, and 10.0 mg L⁻1 under different irrigation regimes (100%, 80%, and 60% of the recommended irrigation rate).

A two-year field experiment was conducted under arid conditions to assess the effects of these treatments on plant growth, yield, photosynthetic pigments, nutrient uptake, and water use efficiency (WUE). Peanut plants were exposed to three irrigation levels (100%, 80%, and 60%), and foliar treatments were applied at specific growth stages. Photosynthetic parameters, including chlorophyll and carotenoid content, were measured alongside growth and yield attributes to determine treatment efficacy.

The application of Metformin at 7.5 mg L⁻1 under 80% irrigation significantly improved plant height (76.9 cm), branch number (17.7 per plant), fresh weight (2928.5 kg acre⁻1), dry biomass (329.1 kg acre⁻1), and total seed yield (1593.9 kg acre⁻1) compared to other treatments. Additionally, water use efficiency (WUE) increased by 50.8% in plants treated with Metformin at 7.5 mg L⁻1 under 80% irrigation compared to untreated plants. The highest chlorophyll content (1.27 mg g⁻1 FW) and carotenoid levels (2.87 mg g⁻1 FW) were observed with Metformin at 7.5 mg L⁻1 under 100% irrigation, indicating improved photosynthetic performance.

Foliar application of Metformin at 7.5 mg L⁻1 under 80% irrigation effectively enhances peanut growth, yield, and WUE, providing a sustainable strategy to mitigate drought stress effects. This treatment balances crop productivity and water conservation, making it a viable approach for peanut cultivation in water-limited environments.

- Foliar application of Metformin at 7.5 mg L⁻¹ significantly improves peanut growth, yield, and water use efficiency under drought stress.

- Peanut plants treated with Metformin exhibit increased plant height, branch number, fresh and dry biomass, and seed yield.

- The combination of Metformin at 7.5 mg L⁻¹ with 80% irrigation optimally enhances yield while conserving water resources.

- Metformin application increases chlorophyll and carotenoid content, supporting improved photosynthesis and plant vigor.

- The study demonstrates that Metformin can serve as an effective, eco-friendly bio-stimulant for peanut cultivation in water-scarce regions.