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effect on plants. Hence, the overall prediction of positive and negative effects of
even same type of nanoparticles is difficult. Further, some NPs such as CuO, Pb,
CeO 2 , QDs, TiO 2 , Au, Ag, and La 2 O 3 NPs can breach the trophic levels. They have
the tendency to transfer through trophic levels to reach the highest consumer level
of the food chain. So, precise and thorough phytotoxicity evaluation of nanoparticles is urgently required on a case-to-case basis before their industrial-scale production and application.
Keywords Nanoparticles · Plant growth · Root growth · Photosynthesis · Seed
germination · Plant biomass
10.1 Introduction
Nanoparticles (NPs) possess distinct physical and chemical properties due to their
unique small size, shape, and surface chemistry (Roduner 2006; Handy et al. 2008;
Kumar and Yadav 2009; Stampoulis et al. 2009). Interestingly, NPs possess higher
number of surface atoms due to more surface area than their bulk counterparts. So,
the surface reactivity of the material in the nanometer range is more than in the bulk
form (Karakoti et al. 2006; Auffan et al. 2009). Hence, NPs have superior catalytic
activity than their usual bulk counterparts (Reier et al. 2012; Schauermann et al.
2013). However, surface reactivity of NPs is also directly related to their toxicity
behavior. Therefore, surface reactivity may be beneficial for catalytic applications,
while the same key feature may impart toxicity to living organisms (Huang et al.
2010; Duffin et al. 2007; Nel et al. 2007). Yet, it is interesting to evidence the
increasing demand for NP-based products on a day-by-day basis, when the market
is already occupied with NP-containing products.
Applications of NPs in daily-use products mean their uninterrupted exposure to
the environment, plants, animals, and humans (Hristozov and Malsch 2009). The
toxic effect of NPs on animals is well studied as compared to plants (Kumar et al.
2012; Kumar et al. 2014). Reports document the positive as well as negative effects
of NPs on plant health, growth, and development (Cushen et al. 2012; Lee et al.
2013; Duncan and Pillai 2015). The number of studies reporting toxicity evaluation
of NPs on plants has increased in the last 5 years. The present article thus discusses
the interaction of NPs with plants in detail, with special focus on the mechanism of
phytostimulatory and phytotoxic effects of NPs.
10.2 Plant–NP Interactions
Plants are the primary producers and first footstep of all (terrestrial) food chains and
food webs. Just like nutrients, plants can uptake NPs from the soil (Rico et al. 2011a,
b). Plants may be directly exposed to NPs by the use of NP-based agricultural
V. Kumar et al.
effect on plants. Hence, the overall prediction of positive and negative effects of
even same type of nanoparticles is difficult. Further, some NPs such as CuO, Pb,
CeO 2 , QDs, TiO 2 , Au, Ag, and La 2 O 3 NPs can breach the trophic levels. They have
the tendency to transfer through trophic levels to reach the highest consumer level
of the food chain. So, precise and thorough phytotoxicity evaluation of nanoparticles is urgently required on a case-to-case basis before their industrial-scale production and application.
Keywords Nanoparticles · Plant growth · Root growth · Photosynthesis · Seed
germination · Plant biomass
10.1 Introduction
Nanoparticles (NPs) possess distinct physical and chemical properties due to their
unique small size, shape, and surface chemistry (Roduner 2006; Handy et al. 2008;
Kumar and Yadav 2009; Stampoulis et al. 2009). Interestingly, NPs possess higher
number of surface atoms due to more surface area than their bulk counterparts. So,
the surface reactivity of the material in the nanometer range is more than in the bulk
form (Karakoti et al. 2006; Auffan et al. 2009). Hence, NPs have superior catalytic
activity than their usual bulk counterparts (Reier et al. 2012; Schauermann et al.
2013). However, surface reactivity of NPs is also directly related to their toxicity
behavior. Therefore, surface reactivity may be beneficial for catalytic applications,
while the same key feature may impart toxicity to living organisms (Huang et al.
2010; Duffin et al. 2007; Nel et al. 2007). Yet, it is interesting to evidence the
increasing demand for NP-based products on a day-by-day basis, when the market
is already occupied with NP-containing products.
Applications of NPs in daily-use products mean their uninterrupted exposure to
the environment, plants, animals, and humans (Hristozov and Malsch 2009). The
toxic effect of NPs on animals is well studied as compared to plants (Kumar et al.
2012; Kumar et al. 2014). Reports document the positive as well as negative effects
of NPs on plant health, growth, and development (Cushen et al. 2012; Lee et al.
2013; Duncan and Pillai 2015). The number of studies reporting toxicity evaluation
of NPs on plants has increased in the last 5 years. The present article thus discusses
the interaction of NPs with plants in detail, with special focus on the mechanism of
phytostimulatory and phytotoxic effects of NPs.
10.2 Plant–NP Interactions
Plants are the primary producers and first footstep of all (terrestrial) food chains and
food webs. Just like nutrients, plants can uptake NPs from the soil (Rico et al. 2011a,
b). Plants may be directly exposed to NPs by the use of NP-based agricultural
V. Kumar et al.