Figure 1
Green beans cv. ‘Strike’ plants under greenhouse conditions at Universidad Autónoma of Chihuahua, Mexico.
Figure 2
(A and B) Sample morphology of ZnO NPs by scanning electron microcopy and (C and D) transmission electron microscopy (Ponce-García et al., 2019). NPs, nanoparticles.
Figure 3
(A) Elemental analysis (chemical composition) by energy dispersive X-ray scattering and (B) crystalline structure by X-ray diffraction of the sample ZnO NPs (Ponce-García et al., 2019). NPs, nanoparticles.
Figure 4
Zn2+ concentrations in leaflet, stem, root and pods of the green bean cv. ‘Strike’ sprayed with ZnSO4 and ZnO NPs. The data shown are mean values ± standard deviations (n = 10). Bars with the same letter are not significantly different according to Tukey's test (p ≤ 0.05). NPs, nanoparticles.
Figure 5
Effect of application of ZnSO4 and ZnO NPs on biomass accumulation and yield (fresh pods) in the green bean cv. ‘Strike’. NPs, nanoparticles.
Table 1
Changes in concentrations of photosynthetic pigments, bioactive compounds and antioxidant capacities in leaflets of the green bean cv. ‘Strike’ following applications of ZnSO4 and ZnO NPs.
| Treatment | Chl | TC | TAn | Sucrose | TP | TFl | AC | |
|---|---|---|---|---|---|---|---|---|
| a | b | |||||||
| Control | 11.41 b | 7.70 b | 2.91 a | 1.05 a | 5.06 b | 3.37 a | 0.32 a | 62.90 a |
| ZnSO4 | 12.62 b | 8.24 b | 2.14 a | 1.24 a | 6.38 a | 3.55 a | 0.42 a | 72.31 a |
| ZnO NPs | 15.40 a | 11.64 a | 1.58 a | 1.50 a | 5.53 ab | 3.20 a | 0.44 a | 56.57 a |
[i] Data are expressed on a fresh-weight basis. Values with the same letter within a column are not significantly different according to Tukey's test (p ≤ 0.05).
[ii] AC, antioxidant capacity (% DPPH inhibition); Chl, chlorophyll (μg · g−1); NPs, nanoparticles; TC, total carotenoids (μg · g−1); TAn, total anthocyanins (mg cyanidin-3-glucoside · 100 g−1); Sucrose (mg · g−1); TP, total phenols (mg GAE · 100 g−1); TFl, total flavonoids (mg CE · 100 g−1); ZnO NPs, zinc oxide nanoparticles.
Table 2
Concentrations of sucrose, TP, TFl and AC in pods and seeds of the green bean cv. ‘Strike’ by supplying ZnSO4 and ZnO NPs.
| Organ | Treatment | Sucrose (mg · g−1) | TP (mg GAE · 100 g−1) | TFl (mg CE · 100 g−1) | AC (% DPPH inhibition) |
|---|---|---|---|---|---|
| Pod | Control | 10.87 a | 1.96 b | 0.061 a | 12.36 b |
| ZnSO4 | 10.89 a | 1.80 b | 0.074 a | 18.60 a | |
| ZnO NPs | 15.06 a | 2.53 a | 0.092 a | 21.39 a | |
| Seed | Control | 12.90 a | 2.18 b | 0.109 a | 71.15 a |
| ZnSO4 | 14.92 a | 2.16 b | 0.077 b | 70.96 a | |
| ZnO NPs | 17.87 a | 4.15 a | 0.136 a | 70.48 a |
[i] Data are expressed on a dry-weight basis. Values with the same letter within a column are not significantly different according to Tukey's test (p ≤ 0.05).
[ii] AC, antioxidant capacity; DPPH, 2,2-diphenyl-1-picrylhydrazyl; NPs, nanoparticles; TP, total phenols; TFl, total flavonoids; ZnO NPs, zinc oxide nanoparticles.