Table 4.
Contents of photosynthetic pigments and their ratios (expressed as % of control) in leaves after 7 days of tobacco plants exposure to 0, 25, 50, and 100 µM AgNP-citrate, AgNP-PVP, AgNP-CTAB, and AgNO in a liquid ½ strength MS medium. VAZ—violaxanthin, antheraxanthin and zeaxanthin (xanthophyll cycle pool), chl a/b—chlorophyll a/b, car/chl—carotenoids/chlorophyll, (AZ)/(VAZ)—de-epoxidation state of xanthophylls. Values are the means ± standard error of three different experiments, each with three replicates. Columns marked with different letters indicate that treatments are significantly different at the p ≤ 0.05 levels (LSD test); capital letters mark the differences among AgNP concentrations as well as control, small letters mark the differences among AgNO3 concentrations as well as control, while asterisks (*) mark the differences among different treatments of the same concentration.
| Treatments | AgNP or AgNO3 (µM) | Chlorophylls | Carotenoids | VAZ | chl a/b | car/chl | (AZ)/(VAZ) |
|---|---|---|---|---|---|---|---|
| as % of control | |||||||
| Control | 0 | 100.00 ± 3.10 | 100.00 ± 5.17 | 100.00 ± 3.80 | 100.00 ± 2.54 | 100.00 ± 2.16 | 100.00 ± 4.78 |
| 25 | 104.22 ± 2.15 A | 111.53 ± 3.69 *,a,A | 99.30 ± 2.36 b,AB | 99.01 ± 0.34 a,A | 107.11 ± 1.96 *,A | 113.30 ± 2.59 *,b,A | |
| AgNP-citrate | 50 | 97.99 ± 2.04 B | 102.18 ± 2.65 b,A | 92.78 ± 1.26 b | 93.20 ± 1.49 *,b,B | 104.39 ± 0.80 *,A | 130.85 ± 2.14 *,a,A |
| 100 | 104.95 ± 1.53 A | 109.42 ± 1.51*,ab,A | 115.85 ± 1.30 *,a,A | 102.64 ± 0.32 a,A | 104.41 ± 1.19 *,A | 94.10 ± 3.92 c,B | |
| 25 | 95.86 ± 2.39 B | 86.89 ± 5.23 *,B | 87.45 ± 1.57 *,C | 98.03 ± 0.70 A | 90.57 ± 3.25 *,B | 94.55 ± 2.25 ab,C | |
| AgNP-PVP | 50 | 90.41 ± 1.43 *,C | 80.74 ± 3.15 *,B | 88.38 ± 1.17 * | 100.96 ± 0.50 A | 89.51 ± 4.60 *,C | 102.77 ± 2.80 a,C |
| 100 | 91.06 ± 0.61 *,AB | 82.96 ± 2.89 *,B | 89.17 ± 1.90 *,B | 98.56 ± 0.07 B | 91.17 ± 2.89 *,B | 89.34 ± 1.60 *,b,BC | |
| 25 | 98.22 ± 2.62 a,AB | 88.07 ± 3.60 *,a,B | 92.09 ± 5.05 a,BC | 99.43 ± 0.76 A | 89.58 ± 1.25 *,a,B | 100.48 ± 3.47 a,BC | |
| AgNP-CTAB | 50 | 91.55 ± 2.97 *,b,C | 93.43 ± 4.48 *,a,A | 88.78 ± 2.57 *,b | 99.25 ± 0.57 A | 103.39 ± 1.77 b,AB | 105.58 ± 1.62 a,C |
| 100 | 77.82 ± 3.68 *,c,B | 78.68 ± 4.38 *,b,B | 78.60 ± 4.09 *,b,B | 97.85 ± 2.14 BC | 101.02 ± 1.27 b,A | 85.04 ± 0.45 *,b,C | |
| 25 | 103.54 ± 2.01 a,A | 106.76 ± 6.84 a,A | 109.23 ± 3.45 a,A | 92.82 ± 0.64 *,B | 102.94 ± 4.71 A | 109.50 ± 3.15 *,AB | |
| AgNO3 | 50 | 104.77 ± 1.42 a,A | 101.60 ± 1.76 a,A | 96.89 ± 1.39 a | 90.69 ± 0.58 *,B | 97.02 ± 1.92 BC | 116.40 ± 1.28 *,B |
| 100 | 86.15 ± 7.58 *,b,B | 85.97 ± 10.04 *,b,B | 83.37 ± 7.93 *,b,B | 94.50 ± 0.35 *,C | 99.27 ± 3.56 A | 109.97 ± 2.15 *,A | |