Differential Phytotoxic Impact of Plant Mediated Silver Nanoparticles (AgNPs) and Silver Nitrate (AgNO3) on Brassica sp

Kanchan Vishwakarma; Shweta; Neha Upadhyay; Jaspreet Singh; Shiliang Liu; Vijay P Singh; Sheo M Prasad; Devendra K Chauhan; Durgesh K Tripathi; Shivesh Sharma

doi:10.3389/fpls.2017.01501

Differential Phytotoxic Impact of Plant Mediated Silver Nanoparticles (AgNPs) and Silver Nitrate (AgNO₃) on Brassica sp

Front Plant Sci. 2017 Oct 12:8:1501. doi: 10.3389/fpls.2017.01501. eCollection 2017.

Authors

Kanchan Vishwakarma¹, Shweta², Neha Upadhyay¹, Jaspreet Singh¹, Shiliang Liu^{3

4}, Vijay P Singh⁵, Sheo M Prasad⁶, Devendra K Chauhan², Durgesh K Tripathi⁷, Shivesh Sharma^{1

7}

Affiliations

¹ Department of Biotechnology, Motilal Nehru National Institute of Technology Allahabad, Allahabad, India.
² D D Pant Interdisciplinary Research Lab, Department of Botany, University of Allahabad, Allahabad, India.
³ College of Landscape Architecture, Sichuan Agricultural University, Chengdu, China.
⁴ College of Agriculture, Food and Natural Resources, University of Missouri, Columbia, MO, United States.
⁵ Government Ramanuj Pratap Singhdev Post Graduate College, Baikunthpur, India.
⁶ Ranjan Plant Physiology and Biochemistry Laboratory, Department of Botany, University of Allahabad, Allahabad, India.
⁷ Centre for Medical Diagnostic and Research, Motilal Nehru National Institute of Technology Allahabad, Allahabad, India.

Abstract

Continuous formation and utilization of nanoparticles (NPs) have resulted into significant discharge of nanosized particles into the environment. NPs find applications in numerous products and agriculture sector, and gaining importance in recent years. In the present study, silver nanoparticles (AgNPs) were biosynthesized from silver nitrate (AgNO₃) by green synthesis approach using Aloe vera extract. Mustard (Brassica sp.) seedlings were grown hydroponically and toxicity of both AgNP and AgNO₃ (as ionic Ag⁺) was assessed at various concentrations (1 and 3 mM) by analyzing shoot and root length, fresh mass, protein content, photosynthetic pigments and performance, cell viability, oxidative damage, DNA degradation and enzyme activities. The results revealed that both AgNPs and AgNO₃ declined growth of Brassica seedlings due to enhanced accumulation of AgNPs and AgNO₃ that subsequently caused severe inhibition in photosynthesis. Further, the results showed that both AgNPs and AgNO₃ induced oxidative stress as indicated by histochemical staining of superoxide radical and hydrogen peroxide that was manifested in terms of DNA degradation and cell death. Activities of antioxidants, i.e., ascorbate peroxidase (APX) and catalase (CAT) were inhibited by AgNPs and AgNO_3. Interestingly, damaging impact of AgNPs was lesser than AgNO₃ on Brassica seedlings which was due to lesser accumulation of AgNPs and better activities of APX and CAT, which resulted in lesser oxidative stress, DNA degradation and cell death. The results of the present study showed differential impact of AgNPs and AgNO₃ on Brassica seedlings, their mode of action, and reasons for their differential impact. The results of the present study could be implied in toxicological research for designing strategies to reduce adverse impact of AgNPs and AgNO₃ on crop plants.

Keywords: AgNO3; AgNPs; Brassica; photosynthetic parameters; plant growth.