Effects of silver nanoparticles on the growth, gas exchange capacity and photosystem II performance in purslane (Portulaca oleracea L.) plants

Document Type : Research Paper

Authors

1 Department of Biology, Faculty of Science, Islamshahr Branch, Islamic Azad University, Islamshahr, Iran.

2 Department of Biology, Science and Research Branch Islamic Azad University Tehran Iran

3 Medicinal Plants Research Center, Shahed University, Tehran, Iran

Abstract

With the dramatic increase in nanotechnologies, it has become probable that biological systems will be exposed to an excess of nanoparticles (NPs). Purslane (Portulaca oleracea L.) is an annual grassy plant that has some pharmacological properties such as antibacterial, analgesic, wound healing, skeletal muscle-relaxant, anti-inflammatory and a radical scavenger. In this study, the effect of different concentrations of silver nanoparticles (0, 2.5, 5, 10, 20, 40 and 80 mg/L) on the growth and biomass production, photosynthetic pigments, proline, flavonoid and phenolic compounds, gas exchange capacity and chlorophyll fluorescence parameters were investigated in purslane plants. The results showed that AgNPs treatments significantly inhibited biomass production and the growth of root and shoot, and decreased the content of chlorophylls a and b at high concentrations (20, 40 and 80 mg/L), while, the AgNPs treatments increased the content of carotenoids, anthocyanins and phenolic compounds compared to control treatment. By increasing the concentration of AgNPs, photosynthetic rate, transpiration rate, stomatal conductance, the maximal quantum yield of PSII photochemistry, photochemical quenching coefficient and effective quantum yield of PSII photochemistry declined. The measurements of Chl a fluorescence showed that strong evidence of inhibitory effects on energy transfer from light-harvesting complexes to reaction centres, the deterioration of the PSII water splitting system and the inactivation of PSII reaction centres at high concentrations of AgNPs. In conclusion, our results demonstrated that AgNPs induced an inhibitory mechanism on photosynthetic processes and biomass of purslane plants.

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Articles in Press, Accepted Manuscript
Available Online from 20 October 2021
  • Receive Date: 09 November 2020
  • Revise Date: 26 July 2021
  • Accept Date: 28 September 2021
  • First Publish Date: 20 October 2021