In recent years, the potential use of polymeric soft NMs in
delivery of bio-molecules in a smart manner and for developing new mythologies of genetic engineering in plants to
enhance their defense mechanisms and induction of growth
and development is being actively pursued, worldwide
(Sanzari et al. 2019).
There are some major bottlenecks in use of ENPs, which
are primarily checking the progress of NMs application in
plant growth are: (i) design and synthesis of safe NMs;
(ii) understanding mechanisms of NMs uptake and mobilization in plants, and, (iii) the lack of global multidisciplinary collaboration for adequate development and
controlled use of nano-applications in plants (Sanzari et al.
2019). Despite, these obvious hurdles to be resolve in years
to come, we have multiple nano-applications to boost agricultural development indirectly via controlled release of
agrochemicals and smart monitoring systems, to manage
agricultural production, cost effectively and environmentally
sound manner. Nanotechnology has shown promising
observations in laboratory tests in controlling the overuse of
agricultural inputs and causing negligible impact on the
environment. In this respect, metal oxide nanoparticles offer
promising perspective for the development of effective
nano-scale formulations of fertilizers/pesticides for their
controlled release capacity and targeted delivery, in sharp
contrast to the conventional fertilizers and pesticides.
3.2.1 Nano-Fertilizers
Quite recently, nano-fertilizers have been recognized as
novel nutrient delivery tools, utilizing nanoparticles of C,
Mn, Fe, and ZnO (Liu and Lal 2015). Researchers across the
globe have shown that some engineered NMs can increase
plant growth in certain concentration ranges, mostly at
smaller concentrations. Several studies showed that
nanoparticles of essential minerals affected plant growth,
depending on their size, concentration, composition, and
mode of application. It was reported to enhance increasing
crop yields promoting germination, seedling growth,
affecting photosynthetic activity, N metabolism, and changes
in gene expression (Tapan and Sivakoti 2019). Also, their
use in nano-fertilizers can increase the agronomic yields
many fold with minimum environmental pollution. Specifically, developing nitrogen and phosphorous macronutrient
nano-fertilizers are being given a high research and development priority in current times, both for food production
and environmental protection. For example, hydroxyapatite
nanoparticles, being used as phosphorous nano-fertilizers
today, have been reported to enhance the soybean growth
rate and yield considerably, as compared to the ordinary
phosphorous fertilizers (Liu and Lal 2015). Also, the slower
release of phosphate from the nano-fertilizer contributes to
maintain the soil fertility along with eutrophication,
nullifying the runoff or leaching (Liu and Lal 2015). Similarly, Zn deficiency, a key factor limiting agricultural yield,
particularly in alkaline soils (Sadeghzadeh 2013), can easily
be ameliorated with the use of Zn nanoparticles, in a
cost-effective manner. Different nano-fertilizers and
nano-pesticides such as Ag, Zn, Fe, Ti, P, Mo, and polymer
nanoparticles have shown significant potential as plant
growth promoting and pest control agent. Similarly, different
kinds of nano-technological tools such as (materials, formulations, composites, emulsions, and encapsulations) have
all shown promising result in providing increased nutrition
to plants and targeted toxins to the concerned pests in a
precise and controlled manner.
Recent studies stated that nanoparticles, made up of
essential minerals and non-essential elements, affect plant
physiological processes and growth considerably, which
primarily depends on size, composition, concentration, and
type of application (via foliar and soil routes).
Nano-fertilizers may contain nano-zinc, iron, silica and
titanium dioxide, InP/ZnS core shell QDs, ZnCdSe/ZnS core
shell QDs, Mn/ZnSe QDs, core shell QDs, gold nano-rods,
etc. However, comprehensive studies on uptake, fate in
biological systems, and toxic influence of several metal
oxide NPs (viz., Al 2 O 3 , CeO 2 , TiO 2 , FeO, and ZnO) were
studied intensively in agricultural production, which equally
lauds for their cautious use, as well (Dimkpa 2014; Zhang
et al. 2016; Parada et al. 2019a, b).
3.2.2 Nano-pesticides
The potential role of NMs in plant protection and food
production is still in infancy. Insect pests, affecting plants as
well as stored foods, may be controlled with the use of ENPs
(Khot et al. 2012). It has been observed that nanoencapsulated pesticides are released slowly in the applied
system and shows greater solubility, permeability, specificity, and stability (i.e., long-lasting pest control efficacy)
(Bhattacharyya et al. 2016). Use of such nano-encapsulated
agricultural tool leads to the development of non-toxic and
promising pesticide delivery systems for better control of
such pests with reduced dose and no associated off-site harm
to human life and environmental health (Bhattacharyya et al.
2016; Grillo et al. 2016; Nuruzzaman et al. 2016). Nanoencapsulation is designed for desired chemicals delivery
to the target biological process. Some products such as
Karate ZEON, Ospray’s Chyella, Subdue MAXX,
Penncap-M, Banner MAXX, Primo MAXX, Subdue
MAXX, etc., are available in market as micro-suspensions.
Organic and polymeric ENPs as nano-capsules/nanospheres
have been used in agro-ecosystem as nano-carriers for
application of herbicides. For example, polymeric ENP is
highly biocompatible and is being largely used for atrazine
encapsulation, a potent herbicide. Similarly, triazine-coated
8
P. Srivastava et al.
delivery of bio-molecules in a smart manner and for developing new mythologies of genetic engineering in plants to
enhance their defense mechanisms and induction of growth
and development is being actively pursued, worldwide
(Sanzari et al. 2019).
There are some major bottlenecks in use of ENPs, which
are primarily checking the progress of NMs application in
plant growth are: (i) design and synthesis of safe NMs;
(ii) understanding mechanisms of NMs uptake and mobilization in plants, and, (iii) the lack of global multidisciplinary collaboration for adequate development and
controlled use of nano-applications in plants (Sanzari et al.
2019). Despite, these obvious hurdles to be resolve in years
to come, we have multiple nano-applications to boost agricultural development indirectly via controlled release of
agrochemicals and smart monitoring systems, to manage
agricultural production, cost effectively and environmentally
sound manner. Nanotechnology has shown promising
observations in laboratory tests in controlling the overuse of
agricultural inputs and causing negligible impact on the
environment. In this respect, metal oxide nanoparticles offer
promising perspective for the development of effective
nano-scale formulations of fertilizers/pesticides for their
controlled release capacity and targeted delivery, in sharp
contrast to the conventional fertilizers and pesticides.
3.2.1 Nano-Fertilizers
Quite recently, nano-fertilizers have been recognized as
novel nutrient delivery tools, utilizing nanoparticles of C,
Mn, Fe, and ZnO (Liu and Lal 2015). Researchers across the
globe have shown that some engineered NMs can increase
plant growth in certain concentration ranges, mostly at
smaller concentrations. Several studies showed that
nanoparticles of essential minerals affected plant growth,
depending on their size, concentration, composition, and
mode of application. It was reported to enhance increasing
crop yields promoting germination, seedling growth,
affecting photosynthetic activity, N metabolism, and changes
in gene expression (Tapan and Sivakoti 2019). Also, their
use in nano-fertilizers can increase the agronomic yields
many fold with minimum environmental pollution. Specifically, developing nitrogen and phosphorous macronutrient
nano-fertilizers are being given a high research and development priority in current times, both for food production
and environmental protection. For example, hydroxyapatite
nanoparticles, being used as phosphorous nano-fertilizers
today, have been reported to enhance the soybean growth
rate and yield considerably, as compared to the ordinary
phosphorous fertilizers (Liu and Lal 2015). Also, the slower
release of phosphate from the nano-fertilizer contributes to
maintain the soil fertility along with eutrophication,
nullifying the runoff or leaching (Liu and Lal 2015). Similarly, Zn deficiency, a key factor limiting agricultural yield,
particularly in alkaline soils (Sadeghzadeh 2013), can easily
be ameliorated with the use of Zn nanoparticles, in a
cost-effective manner. Different nano-fertilizers and
nano-pesticides such as Ag, Zn, Fe, Ti, P, Mo, and polymer
nanoparticles have shown significant potential as plant
growth promoting and pest control agent. Similarly, different
kinds of nano-technological tools such as (materials, formulations, composites, emulsions, and encapsulations) have
all shown promising result in providing increased nutrition
to plants and targeted toxins to the concerned pests in a
precise and controlled manner.
Recent studies stated that nanoparticles, made up of
essential minerals and non-essential elements, affect plant
physiological processes and growth considerably, which
primarily depends on size, composition, concentration, and
type of application (via foliar and soil routes).
Nano-fertilizers may contain nano-zinc, iron, silica and
titanium dioxide, InP/ZnS core shell QDs, ZnCdSe/ZnS core
shell QDs, Mn/ZnSe QDs, core shell QDs, gold nano-rods,
etc. However, comprehensive studies on uptake, fate in
biological systems, and toxic influence of several metal
oxide NPs (viz., Al 2 O 3 , CeO 2 , TiO 2 , FeO, and ZnO) were
studied intensively in agricultural production, which equally
lauds for their cautious use, as well (Dimkpa 2014; Zhang
et al. 2016; Parada et al. 2019a, b).
3.2.2 Nano-pesticides
The potential role of NMs in plant protection and food
production is still in infancy. Insect pests, affecting plants as
well as stored foods, may be controlled with the use of ENPs
(Khot et al. 2012). It has been observed that nanoencapsulated pesticides are released slowly in the applied
system and shows greater solubility, permeability, specificity, and stability (i.e., long-lasting pest control efficacy)
(Bhattacharyya et al. 2016). Use of such nano-encapsulated
agricultural tool leads to the development of non-toxic and
promising pesticide delivery systems for better control of
such pests with reduced dose and no associated off-site harm
to human life and environmental health (Bhattacharyya et al.
2016; Grillo et al. 2016; Nuruzzaman et al. 2016). Nanoencapsulation is designed for desired chemicals delivery
to the target biological process. Some products such as
Karate ZEON, Ospray’s Chyella, Subdue MAXX,
Penncap-M, Banner MAXX, Primo MAXX, Subdue
MAXX, etc., are available in market as micro-suspensions.
Organic and polymeric ENPs as nano-capsules/nanospheres
have been used in agro-ecosystem as nano-carriers for
application of herbicides. For example, polymeric ENP is
highly biocompatible and is being largely used for atrazine
encapsulation, a potent herbicide. Similarly, triazine-coated
8
P. Srivastava et al.