2010; Tan et al. 2018). Considering this, a large number of
studies have been done to assess TiO 2 -NPs induced toxicity
on seed germination, growth and development of plants and
revealed that these NPs caused contrasting (both positive and
negative) impacts on growth and development of plants by
affecting their metabolic processes. Impacts of TiO 2 -NPs on
various plants are documented in Table 2. The literature
related to impacts of TiO 2 -NPs on plants is still emerging. It
is evident from various toxicological studies of TiO 2 -NPs, it
can be concluded that the interaction between plants and
TiO 2 -NPs is very complicated and influenced by properties
of both TiO 2 -NPs and plants as well (Mukherjee et al. 2016).
Here we will classify our studies in following four main
sections:
Table 2 Summary of various studies for the phytotoxicity of titanium dioxide nanoparticles in plants
S. No. Plants
Application of TiO 2 -NPs
Concentrations
Impacts
References
I
Growth and development
1
Spinacia
oleracea
5 nm, anatase, seeds soaked
and foliar application
0.25%
Improved spinach growth and leaf area
Yang et al.
(2007)
2
Allium cepa
21 nm, anatase, suspended on
distilled water
10, 100, and
1000 mg l
−1
Reduced seed germination rate and root
development
Santos Filho
et al. (2019)
3
Zea mays
30 nm, suspended in medium
30 and
1000 mg l
−1
Growth inhibition, inhibited leaf and
roots growth
Asli and
Neuman (2009)
4
Solanum
lycopersicum
22–28.5 nm, anatase, soil and
foliar application
0–1000 mg kg
−1 or
mg l
−1
No effect on seed germination but
promoted growth
Raliya et al.
(2015b)
5
Agropyron
desertorum
21 nm, mixture of anatase and
rutile. Seeds soaked in np
treated water
0, 5, 20, 40, 60 and
80 mg l
−1
Improved seed germination and seedling
growth
Azimiet al.
(2013)
6
Linum
usitatissimum
10–25 nm, anatase, foliar
application
0, 10, 100, and
500 mg l
−1
Increased plant height, number of
subsidiary branches per plant
Aghdam et al.
(2016)
7
Oryza sativa
20 nm, anatase, suspended in
Hoagland nutrient solution
0, 100, 250, and
500 mg l
−1
reduction in biomass
Wu et al. (2017)
8
Arachis
hypogaea
5 nm, anatase, NP powders
blended with soil mixture
50 and
500 mgÁkg
−1
Increased root and shoot biomass
Rui et al. (2018)
9
Triticum
aestivum
< 20 nm, anatase, mixed in
soil
0, 20, 40, 60, 80,
100 mg kg
−1
Promoted growth, increased biomass
Rafique et al.
(2018)
10
Hordeum
vulgare
< 25 nm, anatase, nTiO 2
powder suspensions
0, 500, 1000, and
2000 mg l
−1
reduction in the development and
germination
Mattiello et al.
(2015)
11
Lemna minor
5 -10 nm, anatase, suspended
in medium
0, 10, 50, 100, 200,
1,000, and
2,000 mg l
−1
Inhibited plant growth
Song et al.
(2012)
12
Avena sativa
22- 25 nm, suspended in
distilled water
0, 250, 500 and
1000 mg l
−1
Promotion in seed germination and
seedlings growth
Andersen et al.
(2016)
13
Cucumis
sativus
22- 25 nm, suspended in
distilled water
0, 250, 500 and
1000 mg l
−1
Promoted seed germination rate and
seedling growth
Andersen et al.
(2016)
14
Spinacia
oleracea
Rutile, seeds soaked in
TiO 2- NPs solution
0, 0.25, 0.5, 1.0,
1.5, 2.0, 2.5, 4.0,
and 6.0%
Increased seed vigor index, germination
rate and biomass
Zheng et al.
(2005)
15
Brassica
campestris
27 nm, anatase + rutile, seeds
treatment
0, 100, 500, 1,000,
2,500, and
5,000 mg l
−1
Seed germination and seedling growth
enhanced but not significantly
Song et al.
(2013)
16
Arabidopsis
thaliana
21 and 33 nm, anatase, seeds
treatment
0 and 500 mg l
−1
Increased seed germination and
developmental process
Tumburu et al.
(2015)
17
Hordeum
vulgare
foliar application of nTiO 2
using spray
0 and 2000 ppm
Increased cell growth and enhanced fresh
and dry wt
Janmohammadi
et al. (2016)
18
Foeniculum
vulgare
21 nm, anatase, seeds
treatment
0, 5, 20, 40,
60,80 mg l
−1
Germination rate and biomass increased
Feizi et al.
(2013)
(continued)
56
R. Singh et al.
studies have been done to assess TiO 2 -NPs induced toxicity
on seed germination, growth and development of plants and
revealed that these NPs caused contrasting (both positive and
negative) impacts on growth and development of plants by
affecting their metabolic processes. Impacts of TiO 2 -NPs on
various plants are documented in Table 2. The literature
related to impacts of TiO 2 -NPs on plants is still emerging. It
is evident from various toxicological studies of TiO 2 -NPs, it
can be concluded that the interaction between plants and
TiO 2 -NPs is very complicated and influenced by properties
of both TiO 2 -NPs and plants as well (Mukherjee et al. 2016).
Here we will classify our studies in following four main
sections:
Table 2 Summary of various studies for the phytotoxicity of titanium dioxide nanoparticles in plants
S. No. Plants
Application of TiO 2 -NPs
Concentrations
Impacts
References
I
Growth and development
1
Spinacia
oleracea
5 nm, anatase, seeds soaked
and foliar application
0.25%
Improved spinach growth and leaf area
Yang et al.
(2007)
2
Allium cepa
21 nm, anatase, suspended on
distilled water
10, 100, and
1000 mg l
−1
Reduced seed germination rate and root
development
Santos Filho
et al. (2019)
3
Zea mays
30 nm, suspended in medium
30 and
1000 mg l
−1
Growth inhibition, inhibited leaf and
roots growth
Asli and
Neuman (2009)
4
Solanum
lycopersicum
22–28.5 nm, anatase, soil and
foliar application
0–1000 mg kg
−1 or
mg l
−1
No effect on seed germination but
promoted growth
Raliya et al.
(2015b)
5
Agropyron
desertorum
21 nm, mixture of anatase and
rutile. Seeds soaked in np
treated water
0, 5, 20, 40, 60 and
80 mg l
−1
Improved seed germination and seedling
growth
Azimiet al.
(2013)
6
Linum
usitatissimum
10–25 nm, anatase, foliar
application
0, 10, 100, and
500 mg l
−1
Increased plant height, number of
subsidiary branches per plant
Aghdam et al.
(2016)
7
Oryza sativa
20 nm, anatase, suspended in
Hoagland nutrient solution
0, 100, 250, and
500 mg l
−1
reduction in biomass
Wu et al. (2017)
8
Arachis
hypogaea
5 nm, anatase, NP powders
blended with soil mixture
50 and
500 mgÁkg
−1
Increased root and shoot biomass
Rui et al. (2018)
9
Triticum
aestivum
< 20 nm, anatase, mixed in
soil
0, 20, 40, 60, 80,
100 mg kg
−1
Promoted growth, increased biomass
Rafique et al.
(2018)
10
Hordeum
vulgare
< 25 nm, anatase, nTiO 2
powder suspensions
0, 500, 1000, and
2000 mg l
−1
reduction in the development and
germination
Mattiello et al.
(2015)
11
Lemna minor
5 -10 nm, anatase, suspended
in medium
0, 10, 50, 100, 200,
1,000, and
2,000 mg l
−1
Inhibited plant growth
Song et al.
(2012)
12
Avena sativa
22- 25 nm, suspended in
distilled water
0, 250, 500 and
1000 mg l
−1
Promotion in seed germination and
seedlings growth
Andersen et al.
(2016)
13
Cucumis
sativus
22- 25 nm, suspended in
distilled water
0, 250, 500 and
1000 mg l
−1
Promoted seed germination rate and
seedling growth
Andersen et al.
(2016)
14
Spinacia
oleracea
Rutile, seeds soaked in
TiO 2- NPs solution
0, 0.25, 0.5, 1.0,
1.5, 2.0, 2.5, 4.0,
and 6.0%
Increased seed vigor index, germination
rate and biomass
Zheng et al.
(2005)
15
Brassica
campestris
27 nm, anatase + rutile, seeds
treatment
0, 100, 500, 1,000,
2,500, and
5,000 mg l
−1
Seed germination and seedling growth
enhanced but not significantly
Song et al.
(2013)
16
Arabidopsis
thaliana
21 and 33 nm, anatase, seeds
treatment
0 and 500 mg l
−1
Increased seed germination and
developmental process
Tumburu et al.
(2015)
17
Hordeum
vulgare
foliar application of nTiO 2
using spray
0 and 2000 ppm
Increased cell growth and enhanced fresh
and dry wt
Janmohammadi
et al. (2016)
18
Foeniculum
vulgare
21 nm, anatase, seeds
treatment
0, 5, 20, 40,
60,80 mg l
−1
Germination rate and biomass increased
Feizi et al.
(2013)
(continued)
56
R. Singh et al.