Biological Aspects of Selenium and Silicon Nanoparticles in the Terrestrial Environments

Abstract

The application of both selenium (Se) and silicon (Si) could ameliorate different negative effects of abiotic and/or biotic stresses on plant growth. Under salt-stress conditions, selenium and silicon also could improve plant growth as well as increase the activity of enzymatic antioxidants, improving the balance of ions and osmotic adjustment. They could also use as a resistance provider against plant diseases and the attacks of insects as well as a nutrient supplement. They could also maintain the fertility of soils through improving the bioavailability of nutrients in soils for plants. Apart from selenium and silicon, nano-selenium and nano-silicon have gained a great attention nowadays as eco-friendly technologies. These technologies are considered very important for expanding the biological applications of the nanomaterials. These Se- and Si-nanomaterials have been developed in the field of nanotechnology in order to biosynthesize different nanomaterials for more applications. Many organisms recently have been used in biosynthesizing different varieties of inorganic nanomaterials in well-defined chemical composition. Nano-selenium and nano-silicon are considered promising nanoparticles in agriculture due to their significant roles in the biological systems. Many benefits could be gained from using these nanomaterials such as protection of plants against diseases and different stresses. These nanoparticles should be investigated in more details concerning the nano-safety research. Therefore, this chapter focuses on the beneficial roles of selenium and silicon elements for higher plants in the terrestrial environments, especially plant growth, uptake, and metabolism as well as biogenic synthesis of their elements by some organisms.