NPs aid in delaying ageing of chloroplasts caused because of
the photochemical stress (Hong et al. 2005a; b). TiO 2 NPs
initiate RuBisCO carboxylation and favour electron transport chain, thereby pumping photosynthesis (Gao et al.
2006, 2008; Linglan et al. 2008; Qi et al. 2013). Additionally, TiO 2 NPs promote transpiration rate (Lei et al. 2007).
Therefore, plant nanobionics could be used to enhance crop
growth and crop production (Giraldo et al. 2014).
5 Nano-Agrochemicals and Nanobionics
5.1 Nanofertilizers (NFs)
It is extremely crucial to add fertilizers to soil to obtain a
higher yield (Barker and Pilbeam 2015). However, the use of
chemicals has a potential to damage the soil health and the
environment. Unfortunately, the efficiency of fertilizer utilization by crops is around 35–40% (Dijk van and Meijerink
2014). Nanofertilizers (NFs) could be used to increase
nutritional status of soil without damaging the environment
(Naderi and Abedi 2012) and could be used to replace use of
conventional fertilizers (Naderi and Danesh-Shahraki 2011;
Batsmanova et al. 2013). NFs are capable of escalating the
nutrient facilitation to the seeds and boosting nourishment to
seedlings that holistically increases the shoot and root
length. NFs increase the nutrient availability for the leaves
and branches of crops, resulting in crop production
enhancement (Tapan et al. 2010; Stamp and Visser 2012).
NMs are absorbed by the pores available on the roots or the
stomata in leaves (Eichert and Goldbach 2008). NFs could
be taken up by the plants via ion channels and endocytosis
(Rico et al. 2011).
Nanofertilizers could provide nutrients to the plants in
multiple ways. It could be encapsulated in NMs (like CNTs),
coated with polymers or delivered as emulsions (Derosa
et al. 2010). NFs could promote a slow release of nutrients
and avoid the subsequent loss of valuable nutrients. Additionally, NFs could release the nutrients when crops could
directly use them (Derosa et al. 2010). The advantages
related to use of NFs have been shown in Fig. 1.
Nanofertilizers would make the nutrients available to
plants in the following ways:
• In the form of NPs or emulsions, such as CNTs,
fullerenes, SiO 2 and TiO 2 NPs which could directly bring
about changes in the nutritional availability to plants
(Millán et al. 2008).
• Controlled release of nutrients on stimulation by environmental factors, changes in pH or magnetic/ultrasonic
pulses. Types of controlled release include slow release,
quick release or specific release (Aouada and De Moura
2015).
• Complexed with organic polymers (Corradini et al. 2010)
such as zeolites, chitosan or polyacrylic acid to deliver the
nutritional contents to the plants (Ohlsson 1996; Ditta
2012; Servin et al. 2015).
Ammonium charged zeolites enhance phosphate solubility, thereby increasing its plant availability (Dwivedi et al.
2016). Graphene oxide derived NMs extend KNO 3 release,
minimizing its losses (Shalaby et al. 2016). Calcite NMs
applied with SiO 2 , MgO and Fe 2 O 3 NPs improve the
phosphorus, calcium, magnesium, manganese, iron and zinc
uptake (Sabir et al. 2014). Cationic and anionic nutrients
could be delivered in the form of NM emulsions (Subramanian et al. 2015). Application of ZnO NPs along with
fertilizers was shown to double the barley production (Kale
and Gawade 2016). Controlled release of nourishment by
NFs reduces nitrogen loss through leaching by 22% and
through runoff by 25% and enhances the yield of crops (Liu
et al. 2016). Various NFs and their impact on crop yield have
been represented in Table 1.
5.2 Nanosensors (NSs)
Growth of crops is dependent upon adequate climatic conditions and protection from insect and pathogen attack.
Nanosensors (NSs) would help in collecting the data related
to soil, water, plants and climatic conditions, which could
aid in boosting the crop growth (Rai et al. 2012; Alfadul
et al. 2017). NSs could increase the crop yield with meagre
financial requirements (Rai and Ingle 2012). NSs could be
delivered as NPs, nanowires or nanocrystals, by incorporating the physico-chemical properties of NMs (Khiari
2017). NSs could help in the early detection of diseases,
identification of nutritional deficiency and real-time control
of nutrient provisioning and water delivery. Further,
NS-based global positioning system could be installed to
monitor the crops and agricultural lands (El Beyrouthya
2014; Mariano et al. 2014). The variety of data generated
and collected by NSs has been shown in Fig. 2.
A nanosensor is composed of a biological probe, a
transducer and a data recorder. The probe interacts with the
target producing signals, which is converted by the transducer into digital signals and the data recording unit captures
the signals and stores them (Habibi and Vignon 2008;
Espinosa et al. 2016). The data is relayed to the internet for
its analyses and further application (Dufresne et al. 2000).
These NSs could be placed on the aerial parts of plants by
spraying them on these leaves (Marchiol 2018). CNTs have
the potential to act as precise NSs which could aid in pest
control and crop yield enhancement (Alejandro and Rubiales
2009; De La Torre-Roche et al. 2013). Single-walled CNTs
have been reported to augment photo-absorption, increasing
34
A. Kumar et al.
the photochemical stress (Hong et al. 2005a; b). TiO 2 NPs
initiate RuBisCO carboxylation and favour electron transport chain, thereby pumping photosynthesis (Gao et al.
2006, 2008; Linglan et al. 2008; Qi et al. 2013). Additionally, TiO 2 NPs promote transpiration rate (Lei et al. 2007).
Therefore, plant nanobionics could be used to enhance crop
growth and crop production (Giraldo et al. 2014).
5 Nano-Agrochemicals and Nanobionics
5.1 Nanofertilizers (NFs)
It is extremely crucial to add fertilizers to soil to obtain a
higher yield (Barker and Pilbeam 2015). However, the use of
chemicals has a potential to damage the soil health and the
environment. Unfortunately, the efficiency of fertilizer utilization by crops is around 35–40% (Dijk van and Meijerink
2014). Nanofertilizers (NFs) could be used to increase
nutritional status of soil without damaging the environment
(Naderi and Abedi 2012) and could be used to replace use of
conventional fertilizers (Naderi and Danesh-Shahraki 2011;
Batsmanova et al. 2013). NFs are capable of escalating the
nutrient facilitation to the seeds and boosting nourishment to
seedlings that holistically increases the shoot and root
length. NFs increase the nutrient availability for the leaves
and branches of crops, resulting in crop production
enhancement (Tapan et al. 2010; Stamp and Visser 2012).
NMs are absorbed by the pores available on the roots or the
stomata in leaves (Eichert and Goldbach 2008). NFs could
be taken up by the plants via ion channels and endocytosis
(Rico et al. 2011).
Nanofertilizers could provide nutrients to the plants in
multiple ways. It could be encapsulated in NMs (like CNTs),
coated with polymers or delivered as emulsions (Derosa
et al. 2010). NFs could promote a slow release of nutrients
and avoid the subsequent loss of valuable nutrients. Additionally, NFs could release the nutrients when crops could
directly use them (Derosa et al. 2010). The advantages
related to use of NFs have been shown in Fig. 1.
Nanofertilizers would make the nutrients available to
plants in the following ways:
• In the form of NPs or emulsions, such as CNTs,
fullerenes, SiO 2 and TiO 2 NPs which could directly bring
about changes in the nutritional availability to plants
(Millán et al. 2008).
• Controlled release of nutrients on stimulation by environmental factors, changes in pH or magnetic/ultrasonic
pulses. Types of controlled release include slow release,
quick release or specific release (Aouada and De Moura
2015).
• Complexed with organic polymers (Corradini et al. 2010)
such as zeolites, chitosan or polyacrylic acid to deliver the
nutritional contents to the plants (Ohlsson 1996; Ditta
2012; Servin et al. 2015).
Ammonium charged zeolites enhance phosphate solubility, thereby increasing its plant availability (Dwivedi et al.
2016). Graphene oxide derived NMs extend KNO 3 release,
minimizing its losses (Shalaby et al. 2016). Calcite NMs
applied with SiO 2 , MgO and Fe 2 O 3 NPs improve the
phosphorus, calcium, magnesium, manganese, iron and zinc
uptake (Sabir et al. 2014). Cationic and anionic nutrients
could be delivered in the form of NM emulsions (Subramanian et al. 2015). Application of ZnO NPs along with
fertilizers was shown to double the barley production (Kale
and Gawade 2016). Controlled release of nourishment by
NFs reduces nitrogen loss through leaching by 22% and
through runoff by 25% and enhances the yield of crops (Liu
et al. 2016). Various NFs and their impact on crop yield have
been represented in Table 1.
5.2 Nanosensors (NSs)
Growth of crops is dependent upon adequate climatic conditions and protection from insect and pathogen attack.
Nanosensors (NSs) would help in collecting the data related
to soil, water, plants and climatic conditions, which could
aid in boosting the crop growth (Rai et al. 2012; Alfadul
et al. 2017). NSs could increase the crop yield with meagre
financial requirements (Rai and Ingle 2012). NSs could be
delivered as NPs, nanowires or nanocrystals, by incorporating the physico-chemical properties of NMs (Khiari
2017). NSs could help in the early detection of diseases,
identification of nutritional deficiency and real-time control
of nutrient provisioning and water delivery. Further,
NS-based global positioning system could be installed to
monitor the crops and agricultural lands (El Beyrouthya
2014; Mariano et al. 2014). The variety of data generated
and collected by NSs has been shown in Fig. 2.
A nanosensor is composed of a biological probe, a
transducer and a data recorder. The probe interacts with the
target producing signals, which is converted by the transducer into digital signals and the data recording unit captures
the signals and stores them (Habibi and Vignon 2008;
Espinosa et al. 2016). The data is relayed to the internet for
its analyses and further application (Dufresne et al. 2000).
These NSs could be placed on the aerial parts of plants by
spraying them on these leaves (Marchiol 2018). CNTs have
the potential to act as precise NSs which could aid in pest
control and crop yield enhancement (Alejandro and Rubiales
2009; De La Torre-Roche et al. 2013). Single-walled CNTs
have been reported to augment photo-absorption, increasing
34
A. Kumar et al.