Saffron (Crocus sativus L.) is considered as one of the most commonly known medicinal and aromatic plants in the world. A new study has shown that titanium dioxide (TiO2) nanoparticles are able to counteract the adverse effects of UV-B radiation in saffron.
In recent decades industrial activities have increased the concentration of air pollutants in the atmosphere. Some of these pollutants are compounds that contain stable halogens with the ability to damage ozone layer. With the destruction of ozone layer, UV radiations could reach the earth and become a challenge for living organisms.
Side effects of UV-B radiation
The effects of UV-B on plants are inevitable since plants are in constant need of solar radiation. UV radiation impairs photosynthesis, degrades proteins and nucleic acids, causes oxidative stress and destroys photosynthetic pigments. Moreover, UV radiation creates free radicals which impair metabolic equilibrium inside the cells.
The primary adaptation mechanism that plants use against UV radiation is to increase the width of their leaves and the amount of molecules such as flavonoids and anthocyanin to absorb UV-B. Additionally, plant cells have an anti-oxidative defense system which could neutralize devastating effects of reactive oxygen species. This system includes both enzymatic and non-enzymatic processes.
Treating Saffron with TiO2 nanoparticles
Nanoparticles can move into the cells by crossing the pores on the surface of the leaves. Based on their properties, nanoparticles can produce a wide range of physiological and morphological changes within the cells. Titanium dioxide nanoparticles (TiO2 NPs) have all the properties of TiO2. But because of their smaller size, they have an expanded contact surface and thus, an improved function. In the new study, scientists from Urmia university investigated the reaction of TiO2 treated saffron plants towards destructive UV-B exposure. Scientists also investigated the chemical properties and the antioxidant activity of saffron’s stigma and leaves in order to elucidate the effect of TiO2 nanoparticles.
According to the results, loss of mass, decreased elongation and the loss of dissolved sugars were among the adverse effects of UV-B. As expected, the amount of flavonoids, anthocyanin and phenols increased in response to UV radiation in TiO2 treated plants.
Based on the fact that UV-B radiation significantly altered the amount of antioxidant molecules inside the stigma of plants exposed to TiO2 NPs, investigators concluded that these nanoparticles have the potential to decrease the adverse side effects of UV-B radiation. Furthermore, TiO2 NPs could also be used as a mean to increase the amount of antioxidant and thus the nutritional value of saffron.