Biochar Nanoparticles Reduce Ciprofloxacin Accumulation and Restore Growth and Hormonal Balance in Rice Seedlings

Abstract

Ciprofloxacin (CIP), a widely used fluoroquinolone antibiotic, poses a growing environmental concern due to its persistence in agricultural soils and potential adverse effects on crop production. While previous studies have documented CIP’s negative impacts on plant growth, effective strategies to protect crops from antibiotic stress remain limited. Biochar-based approaches show promise, but their application at the nanoscale for antibiotic stress management is largely unexplored. This study demonstrates how biochar nanoparticles (BNPs) effectively mitigate CIP-induced stress in rice seedlings through adsorption mechanisms. Rice seedlings were treated with 5 and 10 mg L⁻¹ CIP, with and without 0.2 g L⁻¹ BNPs. Results showed that CIP significantly disrupted plant growth, decreasing shoot length by 20.5% and root length by 45.2%, along with reduced biomass. Application of BNPs effectively reduced CIP bioavailability by over 80%, leading to a decreased CIP accumulation of 49.7% in shoots and 33.1% in roots. The addition of BNPs mitigated these growth impacts by restoring shoot length to 98.2% of control levels at 5 mg L⁻¹ CIP and improving root growth and biomass accumulation. BNPs also mitigated CIP-induced hormone imbalance, evidenced by a recovery in IAA levels by 8.9%, an increase in 6-BA by 152.6%, and an enhancement in SA levels by 12.7–13.6%. These findings demonstrate the significant potential of nanoscale biochar in reducing antibiotic stress in agricultural systems and provide insights into plant responses under these conditions. This research offers a promising strategy for enhancing crop resilience in areas affected by pharmaceutical pollutants.