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

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 AgNO3. 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.

Biochemical changes in sunflower plant exposed to silver nanoparticles / silver ions

“…In addition, a reduction in root size and lack of root hairs in the Ag-exposed plants was associated with a decrease in size of nearly all parts of the plant. This was more obvious in plants grown in soil amended with Ag + (as AgNO 3 ) than AgNPs, which is consistent with the literature reports [32,33]. Krizkova et al [29] report a decrease of fresh weight in sunflower plants exposed to Ag + , and that this loss increased with time and exposure dose.…”

Microwave-Assisted Green Synthesis and Characterization of Silver Nanoparticles Using Melia azedarach for the Management of Fusarium Wilt in Tomato

“…In the last few decades, extensive research has been done on the effects of NPs on ecosystems including organisms and plants. Being an eco-friendly and a multifactorial biogenic material, application of NPs is receiving attention due to their specific physiochemical properties, serves as an inexpensive approach for assembling of innovative functional materials used almost in every area of science and technology like medicine, engineering, environment, and agriculture (Austin et al, 2014;Majdalawieh et al, 2014;Siripattanakul-Ratpukdi and Furhacker, 2014;Prasad et al, 2016;Vishwakarma et al, 2017). Due to the interdynamic properties of NPs, there are high opportunities to explore the potential of NPs while the nano-elicitive behavior of these minute particles may rely on their nature and methods of synthesis (Jasim et al, 2017).…”

The Effects of Copper and Silver Nanoparticles on Container-Grown Scots Pine (Pinus sylvestris L.) and Pedunculate Oak (Quercus robur L.) Seedlings

“…Many studies have noted the application of various different types of NP corresponding with a linear decline (accompanying increased dosages or concentrations of NPs) in chlorophyll fluorescence as expressed in terms of the Fv/Fm index. At the same time, a lowered content of chlorophyll, changes in chloroplasts, a reduction in the level of activity of enzymes associated with photosynthesis and, in consequence, restrictions on plant growth, are noted [12,26,36,37]. In our research into the maximum value, the efficiency of photosystem II (as Fv/Fm) was found to depend on the type of NP, the concentration and the plant species.…”

“…Higher values for such chlorophyll a fluorescence measurements in Brassica juncea, following the application of AgNPs, were considered to reflect a higher chlorophyll content, and hence favourable changes in enzyme activity from a plant's perspective, capable of stimulating further growth [35]. Other studies point to impaired chlorophyll fluorescence parameters as a result of the application of NPs [12,26,36,37].…”