Foliar spray (3 weeks and 5 weeks old), under salt stress (irrigated with 10 and 20% sea water)
+
+
n/a
Hussein and Abou‐Baker (2018)
20–30
Chickpea
1.5 ppm
Irrigated daily for 15 days
+
+
n/a
Burman et al. (2013)
10 ppm
–
–
n/a
18
Onion
10–40 mg/L
Foliar spray (3 times at 15 days interval)
+
+
+
Laware and Raskar (2014)
35
Eggplant
5–100 mg/L
Coco peat substrate treated with NPs
+
+
n/a
Thunugunta et al. (2018)
10
Cucumber
400–800 mg/kg
Soil application
+
+
+
Zhao et al. (2014)
10
Kidney beans
60–500 mg/kg
Spiked into soil
+
0
0
Medina‐Velo et al. (2017)
10
Green pea
125–500, 2000 mg/kg
Spiked into soil
+
0
n/a
Mukherjee et al. (2014)
10
Soybean
50, 100, and 500 mg/kg
Soil application
+
+
n/a
Priester et al. (2012)
20–50
Wheat
250, 500, and 1000 mg/L
Petri plate and substrate treatment
+
+
+
Tarafdar et al. (2014)
2000 mg/L
–
–
0
5
Cotton
25, 50, 75, 100, and 200 mg/L
Spiked into Hoagland media in hydroponic
+
+
n/a
Venkatachalam et al. (2017)
n/a
Tobacco
0.2, 1, 5, and 25 μm
Spiked into soilless culture (hydroponic)
+
+
+
Tirani et al. (2019)
3.3.2.2 Effects of Zn NPs Used in Agar Media and Hydroponic Application
Zn NPs can promote early plant growth through agar media or hydroponic applications. Ramesh et al. (2014) found a substantial increase in chlorophyll and protein content in wheat through agar application of ZnO NPs (20–50 nm) between 250 and 2000 mg/L with minimal or no toxic effects. Mung bean and chickpea are grown in agar media at 20 and 1 mg/L, showed an increase of root length, root biomass, shoot length, and shoot biomass by 42 and 53%, 41 and 37%, 98 and 6%, and 76
