have been applied in plants to successfully deliver linear,
DNA plasmid and siRNA in Nicotiana benthamiana. Similarly, silicon carbide-based transformation has been
observed as a successful method to deliver DNA in various
plants such as tobacco, maize, rice, soybean, and cotton
(Asad and Arsh 2012). In a similar way, stable genetic
transformation in cotton plants via magnetic nanoparticles
(MNPs) has also been achieved successfully (Zhao et al.
2017). Moreover, genome editing via mesoporous silica
nanoparticles (MSNs) is being tested as a promising
approach in recent scientific studies (Valenstein et al. 2013).
All these novel approaches are intended to bring novelty and
easiness in agricultural production in cost-effective manner.
3.2 Engineered Nano-materials as Stimulant
of Plant Growth
Over the last two decades, ENPs research in medicine and
pharmacology has been significant, especially for diagnostic
or therapeutic purposes (Perrault et al. 2009). Recently, these
NMs are receiving an increased interest in the field of crop
sciences/agronomy, particularly in the application of NMs as
vehicles of agrochemicals or bio-molecules in plants to
enhance crop productivity (Khan et al. 2017). Generally,
ENPs are applied to roots or vegetative part of plants,
preferably to the leaves. Generally, its uptake has been
observed a little more complicated in the soils, as compared
to the aerial parts of the plants (Sanzari et al. 2019). The
uptake, mobilization mechanisms, and biological effects of
these NMs with plant are still in infancy, and it is not a wise
opinion to move with imperfection in field applications,
without knowing their intricate interactions with plants, soil
microorganisms and environment, completely and scientifically. In several studies, specific (low dose) concentrations
of ENPs, foliar spray/irrigation, and carbon nanotubes have
significantly improved plant growth, physiological aspects
(chlorophyll a, b, carotenoid content, photosynthesis, carbohydrates), antioxidants, and plant tolerance against biotic
and abiotic stress (Nafees et al. 2020).
In recent studies, ENPs (particularly, based on carbon,
metal, and metal oxides) influence on plant physiology and
growth showed that it considerably affects seed germination
in higher concentration. For example, zinc (Zn) and copper
(Cu) oxide nanoparticles, being essential micronutrients,
have been observed to act as a significant plant growth
promoting complex (Priyanka et al. 2019). Surprisingly, it
has been noted that various kinds of ENPs affect the plants
ability and behavior, in a differential and sometimes in a
contrasting manner. Some plants are even capable of uptake
and accumulation of ENPs. Carbon nanotubes and Au, SiO 2 ,
ZnO, and TiO 2 nanoparticles have shown potential to
expedite growth of plants, by increasing the uptake of
elements and improved nutrient utilization (Khot et al.
2012). Ag-NPs at low concentrations have shown enhanced
shoot and root growth enhancing chlorophyll production and
antioxidant enzyme activity, limiting production of reactive
oxygen species (ROS) in the plant tissues (Sami et al. 2020).
However, the impact of nanoparticles on plant behavior
depends largely on the size, surface charge, composition,
concentration, and physicochemical properties of the
nanoparticle used, besides the susceptibility of the concerned
plant species (Ma et al. 2010; Lambreva et al. 2015).
Notably, studies show that nanoparticles might be efficient stimulator of plant growth irrespective of their nature.
However, comprehensive experimentations are needed to
optimize their application conditions and identifying their
specific impact on plant’s physiology (Fincheira et al 2020).
The plant cell–ENP interaction leads to a change in plant’s
genetic expression and associated metabolic pathways as
well, which affect plant growth and developments as a
consequence, in a remarkable manner (Ghormade et al.
2011). For example, a pronounced increase in germination
rate of rice and wheat has been observed under carbon
nano-materials, especially CNTs (Wang et al. 2012). The
beneficial impacts of accumulation of nano-materials in
plants, particularly in MWCNTs, ZnO, and Zn, have also
been observed (Hussein et al. 2002). Similarly, TiO 2
nanoparticles have been observed to promote nitrate reductase activity in soybean (Glycine max), enhance water and
nutrient absorption/use, and induce the antioxidant machinery to favor plant’s growth. In a similar research, TiO 2 -
treated seeds have shown 73% higher plant dry weight, due
to thrice higher photosynthetic rates and a considerable rise
(around 45%) in chlorophyll (Mingfang et al. 2013). Also, it
has been found to promote the growth in spinach via
improving nitrogen assimilation and photosynthetic rate. In a
study, Zn nano-materials have shown to promote chlorophyll
production, fertilization, pollen function, and germination
and reduce the susceptibility of plants to drought stress.
However, contrasting findings with other species have also
been observed, signaling more studies to be conducted to
understand ENPs-plant interaction. The influence of ENPs
on various plants differs greatly depending on growth stage,
method, and period of exposure (Khiew et al. 2011). Additionally, symbiotic bacteria and fungi in the soil, associated
with plant roots, have shown controversial interactions in
relation to ENPs. These microscopic entities increase the
heavy metal NPs accumulation in turf grasses, however
reduce the uptake of nano-Ag and nano-FeO in legumes
(Guo and Chi 2014). Therefore, to better understand the
interaction of these ENPs with plants and associated
microflora, new and improved protocols and techniques
(such as magnetic resonance imaging (MRI), microscopy,
and fluorescence spectroscopy) might help in reaching
appropriate scientific conclusion (Srivastava et al. 2019).
Engineered Nanoparticles in Smart Agricultural Revolution …
7
DNA plasmid and siRNA in Nicotiana benthamiana. Similarly, silicon carbide-based transformation has been
observed as a successful method to deliver DNA in various
plants such as tobacco, maize, rice, soybean, and cotton
(Asad and Arsh 2012). In a similar way, stable genetic
transformation in cotton plants via magnetic nanoparticles
(MNPs) has also been achieved successfully (Zhao et al.
2017). Moreover, genome editing via mesoporous silica
nanoparticles (MSNs) is being tested as a promising
approach in recent scientific studies (Valenstein et al. 2013).
All these novel approaches are intended to bring novelty and
easiness in agricultural production in cost-effective manner.
3.2 Engineered Nano-materials as Stimulant
of Plant Growth
Over the last two decades, ENPs research in medicine and
pharmacology has been significant, especially for diagnostic
or therapeutic purposes (Perrault et al. 2009). Recently, these
NMs are receiving an increased interest in the field of crop
sciences/agronomy, particularly in the application of NMs as
vehicles of agrochemicals or bio-molecules in plants to
enhance crop productivity (Khan et al. 2017). Generally,
ENPs are applied to roots or vegetative part of plants,
preferably to the leaves. Generally, its uptake has been
observed a little more complicated in the soils, as compared
to the aerial parts of the plants (Sanzari et al. 2019). The
uptake, mobilization mechanisms, and biological effects of
these NMs with plant are still in infancy, and it is not a wise
opinion to move with imperfection in field applications,
without knowing their intricate interactions with plants, soil
microorganisms and environment, completely and scientifically. In several studies, specific (low dose) concentrations
of ENPs, foliar spray/irrigation, and carbon nanotubes have
significantly improved plant growth, physiological aspects
(chlorophyll a, b, carotenoid content, photosynthesis, carbohydrates), antioxidants, and plant tolerance against biotic
and abiotic stress (Nafees et al. 2020).
In recent studies, ENPs (particularly, based on carbon,
metal, and metal oxides) influence on plant physiology and
growth showed that it considerably affects seed germination
in higher concentration. For example, zinc (Zn) and copper
(Cu) oxide nanoparticles, being essential micronutrients,
have been observed to act as a significant plant growth
promoting complex (Priyanka et al. 2019). Surprisingly, it
has been noted that various kinds of ENPs affect the plants
ability and behavior, in a differential and sometimes in a
contrasting manner. Some plants are even capable of uptake
and accumulation of ENPs. Carbon nanotubes and Au, SiO 2 ,
ZnO, and TiO 2 nanoparticles have shown potential to
expedite growth of plants, by increasing the uptake of
elements and improved nutrient utilization (Khot et al.
2012). Ag-NPs at low concentrations have shown enhanced
shoot and root growth enhancing chlorophyll production and
antioxidant enzyme activity, limiting production of reactive
oxygen species (ROS) in the plant tissues (Sami et al. 2020).
However, the impact of nanoparticles on plant behavior
depends largely on the size, surface charge, composition,
concentration, and physicochemical properties of the
nanoparticle used, besides the susceptibility of the concerned
plant species (Ma et al. 2010; Lambreva et al. 2015).
Notably, studies show that nanoparticles might be efficient stimulator of plant growth irrespective of their nature.
However, comprehensive experimentations are needed to
optimize their application conditions and identifying their
specific impact on plant’s physiology (Fincheira et al 2020).
The plant cell–ENP interaction leads to a change in plant’s
genetic expression and associated metabolic pathways as
well, which affect plant growth and developments as a
consequence, in a remarkable manner (Ghormade et al.
2011). For example, a pronounced increase in germination
rate of rice and wheat has been observed under carbon
nano-materials, especially CNTs (Wang et al. 2012). The
beneficial impacts of accumulation of nano-materials in
plants, particularly in MWCNTs, ZnO, and Zn, have also
been observed (Hussein et al. 2002). Similarly, TiO 2
nanoparticles have been observed to promote nitrate reductase activity in soybean (Glycine max), enhance water and
nutrient absorption/use, and induce the antioxidant machinery to favor plant’s growth. In a similar research, TiO 2 -
treated seeds have shown 73% higher plant dry weight, due
to thrice higher photosynthetic rates and a considerable rise
(around 45%) in chlorophyll (Mingfang et al. 2013). Also, it
has been found to promote the growth in spinach via
improving nitrogen assimilation and photosynthetic rate. In a
study, Zn nano-materials have shown to promote chlorophyll
production, fertilization, pollen function, and germination
and reduce the susceptibility of plants to drought stress.
However, contrasting findings with other species have also
been observed, signaling more studies to be conducted to
understand ENPs-plant interaction. The influence of ENPs
on various plants differs greatly depending on growth stage,
method, and period of exposure (Khiew et al. 2011). Additionally, symbiotic bacteria and fungi in the soil, associated
with plant roots, have shown controversial interactions in
relation to ENPs. These microscopic entities increase the
heavy metal NPs accumulation in turf grasses, however
reduce the uptake of nano-Ag and nano-FeO in legumes
(Guo and Chi 2014). Therefore, to better understand the
interaction of these ENPs with plants and associated
microflora, new and improved protocols and techniques
(such as magnetic resonance imaging (MRI), microscopy,
and fluorescence spectroscopy) might help in reaching
appropriate scientific conclusion (Srivastava et al. 2019).
Engineered Nanoparticles in Smart Agricultural Revolution …
7