5.5.3 Other Abiotic Stresses
The growth, development, and productivity of wheat plants are adversely affected by
other stresses like heavy metal contamination, chilling stress, ultraviolet B radiation,
etc. Heavy metal toxicity induced growth inhibition and oxidative stress in wheat
crops. Recently, López-Luna et al. (2016) assessed the uptake of citrate-coated
magnetite nanoparticles by wheat plants and effect on the bioaccumulation and
toxicity of individual and joint cadmium and chromium levels. The toxic effects of
individual and mixed cadmium and chromium were markedly diminished when the
wheat plants were amended with citrate-coated magnetite nanoparticles, possibly
due to reduction of heavy metal phytoavailability upon adsorption onto magnetite
nanoparticles. In fact, the stabilization of metals and metalloids by reducing mobility, bioavailability, and bioaccessibility can be achieved by applying immobilizing
agents such as nanosized oxides, mainly due to high reactivity and large specific
surface area. Moreover, the addition of magnetite nanoparticles enhanced root length
of the plants. Konate et al. (2017) investigated the physiological mechanisms of
magnetite nanoparticle mitigation of the toxicity of heavy metals (lead, zinc, cadmium, and copper) in wheat seedlings. The addition of magnetite nanoparticles in
1 mM heavy metal solution significantly decreased the growth inhibition and
activated protective mechanisms to reduce oxidative stress induced by heavy metals
in the wheat seedlings. Moreover, the alleviating effect of magnetite nanoparticle is
associated with adsorption capacity of heavy metals and dependent on the increase in
the enzyme activity of superoxide dismutase and peroxidase.
Bhati-Kushwaha et al. (2013) suggested that silver nanoparticle confers an
increased tolerance of wheat plants to cold stress. The results provided clear evidences that seed priming with silver nanoparticles is one of the suitable methods for
increasing seedling vigor and improvement of germination percentage and seedling
growth under chilling stress.
Ultraviolet B radiation negatively influenced growth of wheat seedlings through
interference in photosynthesis due to decreased levels of antioxidants (superoxide
dismutase and peroxidase) and enhanced level of oxidative stress. Recently, Tripathi
et al. (2016) reported that pre-addition of 10 μM silicon nanoparticles protects wheat
seedlings against ultraviolet B radiation stress by protecting photosynthesis and
regulating level of oxidative stress. Silicon nanoparticles protect wheat seedlings
through nitric oxide-mediated triggering of antioxidant defense system, which subsequently counterbalance reactive oxygen species-induced damage to photosynthesis.
5.6 Surveillance, Monitoring, and Detection of Wheat
Disease and Insect Pests
Rapid detection technologies with high sensitivity and selectivity for plant pathogens and insect pests are essential to prevent disease spread and minimize losses to
assure optimal productivity and food security (Kashyap et al. 2016; Sharma et al.
5 Nanotechnology in Wheat Production and Protection
181
The growth, development, and productivity of wheat plants are adversely affected by
other stresses like heavy metal contamination, chilling stress, ultraviolet B radiation,
etc. Heavy metal toxicity induced growth inhibition and oxidative stress in wheat
crops. Recently, López-Luna et al. (2016) assessed the uptake of citrate-coated
magnetite nanoparticles by wheat plants and effect on the bioaccumulation and
toxicity of individual and joint cadmium and chromium levels. The toxic effects of
individual and mixed cadmium and chromium were markedly diminished when the
wheat plants were amended with citrate-coated magnetite nanoparticles, possibly
due to reduction of heavy metal phytoavailability upon adsorption onto magnetite
nanoparticles. In fact, the stabilization of metals and metalloids by reducing mobility, bioavailability, and bioaccessibility can be achieved by applying immobilizing
agents such as nanosized oxides, mainly due to high reactivity and large specific
surface area. Moreover, the addition of magnetite nanoparticles enhanced root length
of the plants. Konate et al. (2017) investigated the physiological mechanisms of
magnetite nanoparticle mitigation of the toxicity of heavy metals (lead, zinc, cadmium, and copper) in wheat seedlings. The addition of magnetite nanoparticles in
1 mM heavy metal solution significantly decreased the growth inhibition and
activated protective mechanisms to reduce oxidative stress induced by heavy metals
in the wheat seedlings. Moreover, the alleviating effect of magnetite nanoparticle is
associated with adsorption capacity of heavy metals and dependent on the increase in
the enzyme activity of superoxide dismutase and peroxidase.
Bhati-Kushwaha et al. (2013) suggested that silver nanoparticle confers an
increased tolerance of wheat plants to cold stress. The results provided clear evidences that seed priming with silver nanoparticles is one of the suitable methods for
increasing seedling vigor and improvement of germination percentage and seedling
growth under chilling stress.
Ultraviolet B radiation negatively influenced growth of wheat seedlings through
interference in photosynthesis due to decreased levels of antioxidants (superoxide
dismutase and peroxidase) and enhanced level of oxidative stress. Recently, Tripathi
et al. (2016) reported that pre-addition of 10 μM silicon nanoparticles protects wheat
seedlings against ultraviolet B radiation stress by protecting photosynthesis and
regulating level of oxidative stress. Silicon nanoparticles protect wheat seedlings
through nitric oxide-mediated triggering of antioxidant defense system, which subsequently counterbalance reactive oxygen species-induced damage to photosynthesis.
5.6 Surveillance, Monitoring, and Detection of Wheat
Disease and Insect Pests
Rapid detection technologies with high sensitivity and selectivity for plant pathogens and insect pests are essential to prevent disease spread and minimize losses to
assure optimal productivity and food security (Kashyap et al. 2016; Sharma et al.
5 Nanotechnology in Wheat Production and Protection
181