Nanoparticles and their Impact on Plants

Abstract

Nanoparticles are atomic or molecular aggregates having dimension between 1 and 100 nm. They posses different physico-chemical (strength, electrical and optical) properties due to the variation in surface area compared with those of their counterpart-bulk materials. The nanoparticles can be made from bulk materials. They can explicate their actions depending on both the chemical composition and the crystalline structure of the particles. Nanoparticles known to be exist from the beginning of the earth history and still occur in the environments like, volcanic dust, lunar dust, mineral composites, etc. Incidental or engineered nanoparticles, also defined as waste or anthropogenic particles, may be formed as the result of manmade industrial processes, like diesel exhaust, coal combustion, welding fumes, etc. These nanomaterials can be grouped as carbon based (fullerene, single-and multi walled carbon nanotube) and metal based (quantum dots, nanogold, nanozinc and nanoaluminum) materials. Their utility spectrum has been increased enormously in the last decade and used as a tool in variety of technological platforms for the study and transformation of biological systems. A few studies have been focused on the effects and mechanisms of nanomaterials on plants. The results of these studies have been reported with the aim to provide further insight into connections between plants and nanomaterials. Nanoscales metal oxides, like TiO 2 , ZnO and Al 2 O 3 dendrimers (nano-sized polymers built from branched units) are capable of performing specific chemical functions. In this context, engineered nanomaterials have received a particular attention for their positive impact in improving, among others, consumer products, pharmaceutics, cosmetics, transportation, energy and also in agriculture. Possibility of the existence of useful nanoparticles in plant tissues and exploitation of their practical benefits seems to be very intriguing. In fact, multi walled nanoparticles known to act at the level of seed germination and root growth in higher plant species including Raphanus sativus, Brassica napus, Lolium multiflorum, Lactuca sativa, Zea mays and Cucumis sativus. In the presence of ZnO nanoparticles the ryegrass biomass significantly reduced, root tip shrank, root epidermal and cortical region highly vacuolated or most of the cells are collapsed at the cortical region. Critical