“…The ionic form of metallic nanoparticles is commonly cited in the published literature as the likely factor attributed to the toxic effects upon biological species (Navarro et al, 2008, Xiu et al, 2012). Yet, the evidence gathered from the published literature in this study suggests that the stimulatory and inhibitory effects of metallic nanoparticles are influenced by both forms of metals depending upon the physical-chemical characteristics of nanoparticles, environmental conditions, soil media, and plant species (Asztemborska et al, 2014, Dimkpa et al, 2013, Gubbins et al, 2011, Kaveh et al, 2013, Kim et al, 2014b, Mustafa et al, 2015, Pokhrel and Dubey, 2013, Pradhan et al, 2015, Qian et al, 2013, Taylor et al, 2014, Yin et al, 2011, Yin et al, 2012.…”