Nanotechnology in Plant Growth Promotion and Protection. Группа авторов

Figure 3.1 Outline of different methods used for the treatment of seeds with Zn NPs and their effects.

Table 3.1 Effects of Zn NPs on germination and seedling growth after application through different modes.

Size and coatings (nm)	Crop	Concentrations	Mode of application	Effects	References
Root growth	Shoot growth	Germination percent
21.3	Lupine	20, 40, and 60 mg/L	Seed priming (12 hours) under salt stress (150 mM NaCl)	+	+	+	Latef et al. (2017)
20	Onion	10 and 20 mg/L	Seed treatment in petri‐plate for 10 days	+	+	+	Raskar and Laware (2014)
		30 and 40 mg/L	Seed treatment in petri‐plate for 10 days	−	−	−
25	Peanut	400 and 1000 mg/L	Seed treatment (3 hours)	+	+	+	Prasad et al. (2012)
		2000 mg/L	Seed treatment (3 hours)	−	−	−
25	Maize	50–2000 mg/L	Seed soaking (3 hours)	+	+	+	Subbaiah et al. (2016)
<100	Brassica	500–1500 mg/L	Seed allowed to grow in treated plain agar for 12 days	−	−	−	Zafar et al. (2016)
<100	Wheat	500 mg/L	Seed treatment (24 hours)	+	+	+	Elhaj Baddar and Unrine (2018)
n/a	Rice	500 and 750 mg/L	Seed treatment till germination	−	−	−	Sheteiwy et al. (2017)
30–60	Rice	5, 10, 15, 20, and 50 mg/L	Seed soaking (1 hour)	+	+	+	Panda (2017)
34	Wheat	25, 50, 75, and 100 mg/L	Seed priming (24 hours)	+	+	+	Munir et al. (2018)
13	Wheat	10, 20, and 50 mg/L	Hydroponic supplement (14 days)	+	+	+	Awasthi et al. (2017)
		100 mg/L		−	+	−
20, 40, and 60	Common Bean	1, 10, 100, and 1000 mg/L	Seed priming (20 minutes)	+	+	o	Savassa et al. (2018)
		5000 mg/L		−	−	−
18	Capsicum	100, 200, and 300 mg/L	Applied during imbibition (72 hours)	+	+	+	Israel García‐López et al. (2018)
		400 and 500 mg/L		−	−	−

      3.2.3 Effects of Seed Treatment on Plant Growth

      Seed treated with ZnO NPs not only protects seeds from microbial infections but also provides Zn to the crops after germination in the easily available form (Masuthi et al. 2009; Farooq et al. 2012). Seed priming with Zn NPs (34 nm) for 24 hours at 100 mg/L increased photosynthetic pigment content by 58% and stomatal conductance by 102% after 65 days of treatment. Moreover, the same treatment increased wheat plant height, tillers per plant, spike length, biomass yield, and grain yield by 16, 69, 87, 58, 36, and 185% respectively (Munir et al. 2018).

      3.2.4 Molecular Mechanisms Involved in Effects of Zn NPs on Seed

      Compare to salt‐based Zn, ZnO NPs can enhance Zn delivery to seeds through the particle‐specific mechanisms. Zhang et al. (2015a) suggested