Improving growth of Solanum melongena L. exposed to lead (Pb) stress using gibberellic acid in combination with Agrobacterium fabrum

Abstract

Lead (Pb), as heavy metal, poses substantial threats to plant health, impeding growth, disrupting nutrient uptake, and inducing oxidative stress. Its interference with crucial processes such as photosynthesis and water uptake, combined with its capacity to accumulate in plant tissues, results in stunted development and compromised overall productivity. To address this issue, the application of gibberellic acid (GA3) emerges as an effective amendment, promoting seed germination, stem elongation, and flowering. Additionally, the inoculation of rhizobacteria, specifically Agrobacterium fabrum (A. fabrum), offers resistance, improved nutrient uptake, and enhanced growth under conditions of heavy metal toxicity. Therefore, the present study was designed to investigate the impact of GA3 and A. fabrum on Solanum melongena L. cultivated under Pb toxicity. The experiment comprised four treatments: control, A. fabrum, 30 mg/L GA3 (30GA3), and A. fabrum + 30GA3, applied in four replications following a completely randomized design. Results indicated that A. fabrum + 30GA3 significantly enhanced Solanum melongena L. shoot and root length, fresh and dry weight over the control under Pb stress. Furthermore, a notable increase in Solanum melongena L. chlorophyll contents, stomatal conductance, transpiration rate, and photosynthetic rate over the control under Pb stress validated the effectiveness of A. fabrum + 30GA3. Additionally, improvements in N, P, and K concentration in roots and shoots confirmed the efficacious functioning of A. fabrum + 30GA3 from the control under Pb stress. In conclusion, A. fabrum + 30GA3 is recommended as an amendment for the mitigation of Pb stress in Solanum melongena L.

Keywords

• Rhizobacteria
• Chlorophyll contents
• Gibberellic acid
• Lead
• Nutrients concentration
• Solanum melongena L