Silver Nanoparticles-Cow Dung Combination Disrupts Physiology, Enzyme Activities with Corresponding Increased Oxidative Stress and Heavy Metal Accumulation in Abelmoschus esculentus.

The effects of a silver nanoparticles (AgNPs)-cow-dung combination on Abelmoschus esculentus physiology, enzyme activities, heavy metal bioaccumulation, and micronutrients were investigated. A. esculentus seedlings were nurtured with foliar application of water, 0.75 mg/L each of AgNPs, cow-dung and AgNPs-cow dung till maturity. AgNPs-cow dung inhibited root and shoot lengths by 12.9% and 24.8%, respectively as opposed to elongation recorded for individual application compared to the control. In contrast to the promotion of photosynthesis, enzyme and antioxidant activities by individual applications, AgNPs-cow dung suppressed more than 50% of these parameters. Implied toxicities of AgNPs-cow dung on A. esculentus manifested in increased malondialdehyde contents with concomitant higher bioaccumulation factor of heavy metals. Cow-dung and AgNPs each stimulated A. esculentus activities in different ways, but their combination was inhibitory, which may be ascribed to the transformed AgNPs in cow-dung and relative availability of toxic metals.