The fate of silver nanoparticles in Lycopersicon esculentu

The advancement of nanotechnology has resulted in the application of nanomaterials in a diverse area including medicine, industry, or agriculture. The vast application of nanomaterials and their potential release into the environment can affect soil and water quality, plants, and subsequently human health through the food chain. Silver nanoparticles (AgNPs) are among the most commonly used nanomaterials. AgNPs released into the environment can be oxidized and be transformed into the ionic form (Ag+) which is more interactive than the particulate form. This study investigated the molecular and physiological responses in tomatoes (Lycopersicon esculentum) exposed to ۳۰ mg/L AgNPs (۲۰nm) for seven days. Plants exposed to AgNO۳ and Hoagland media were subsequently used as positive and negative controls. To determine the concentration of Ag and to distinguish between the particulate and the ionic form of Ag in plant tissues an ICP-MS (NEXION ۳۵۰X) equipped with a nano-detector was used. The concentration of H۲O۲ and MDA, as well as the activity of antioxidative enzymes catalase and peroxidase, were investigated to determine the level of oxidative stress inplants. The expression of membrane transporters H+-ATPase and V-ATPase as well as the expression of enzymes catalase and mitochondrial IDH were studied using RT-q-PCR. Immunofluorescent labeling was used to study the expression of proteins. The analytical analysis showed that both particulate and ionic forms of silver were accumulated in plant tissues confirming that AgNPs can be oxidized in the environment. The physiological analysis showed that the oxidative stress caused by Ag+ was more significant than the particulate form. The expression of H+-ATPase was significantly upregulated upon exposure to AgNPs and AgNO۳ compared to the control group. This study suggests that the higher concentration of Ag+ in plants exposed to all forms of silver changed the electrochemical potential of cells and resulted in the upregulation of H+-ATPaseto send more H+ out of cells. This study provides invaluable information to better understand the fate of metalbased nanomaterials and their effects on plants.

کلیدواژه ها:

Analytical analysis ، Membrane transporters ، Nanoparticles ، Oxidative stress