RESEARCH ARTICLE Environmental effects of nanosilver: impact on castor seed germination, seedling growth, and plant physiology Jyothsna Yasur & Pathipati Usha Rani Received: 28 February 2013 / Accepted: 30 April 2013 / Published online: 24 May 2013 # Springer-Verlag Berlin Heidelberg 2013 Abstract Increasing use of nanoparticles in daily products is of great concern today, especially when their positive and negative impact on environment is not known. Hence, in current research, we have studied the impact of silver nano- particle (AgNPs) and silver nitrate (AgNO 3 ) application on seed germination, root, and shoot length of castor bean, Ricinus communis L. plant. Silver nanoparticles had no significant effects on seedling growth even at higher con- centration of 4,000 mg L -1 , while the silver in bulk form as AgNO 3 applied on the castor bean seeds inhibited the seed germination. Silver uptake in seedlings of the castor seeds on treatment with both the forms of silver was confirmed through atomic absorption spectroscopy studies. The silver nanoparticle and silver nitrate application to castor seeds also caused an enhanced enzymatic activity of ROS en- zymes and phenolic content in castor seedlings. High- performance liquid chromatography analysis of individual phenols indicated enhanced content of parahydroxy benzoic acid. These kinds of studies are of great interest in order to unveil the movement and accumulation of nanoparticles in plant tissues for assessing future applications in the field or laboratory. Keywords Silver nanoparticles . Silver nitrate . Castor plant . Seed germination . Phenols . Oxidative enzymes Abbreviations AAS Atomic absorption spectroscopy AgNPs Silver nanoparticles AgNO 3 Silver nitrate CAT Catalase DLS Dynamic light scattering HPLC High-performance liquid chromatography NP Nanoparticles POD Peroxidase ROS Reactive oxygen species SOD Superoxide dismutase TEM Transmission electron microscope XRD X-ray diffraction Introduction The increasing level of production, use, and disposal of nanomaterials will unavoidably lead in to the environment or air, water, and soil. The progressive usage of nanoparticles (NPs) in several products including agriculture is gaining importance in recent years. The antimicrobial properties of silver have made it as major ingredient in several agricultural products from companies such as Monsanto, Bayer, Syngenta, etc., and also in detergents, plastics, and textiles (Benn and Westerhoff 2008; Blaser et al. 2008). However, use of these products has resulted in the release of NP into the environ- ment. Though silver is known to be one of the most toxic trace metals (Ratte 1999), the mechanism involved in AgNP toxic- ity have not been fully studied. Although great effort has been made, it is still challenging to elucidate whether the toxicity is related to nanoparticles or because of dissolved forms of Ag (Ag + ions) and their co-occurrence with AgNPs. There are only a few studies in which trials have been made to determine the effects of two species in environment. The present study was undertaken to find whether the toxicity of Ag is caused by Responsible editor: Elena Maestri J. Yasur : P. U. Rani (*) Biology and Biotechnology Division, CSIR-Indian Institute of Chemical Technology, Tarnaka, Hyderabad 500007( Andhra Pradesh, India e-mail: usharanipathipati@gmail.com P. U. Rani e-mail: usharani65@yahoo.com P. U. Rani e-mail: purani@iict.res.in Environ Sci Pollut Res (2013) 20:8636–8648 DOI 10.1007/s11356-013-1798-3