Table 4.
Mean comparison shows the main effects of the irrigation levels (Well-watered and water-deficit) and the foliar applications of gamma-aminobutyric acid (GABA) at 0, 0.5, 1 and 2 mM on the vegetative growth, lipid peroxidation, water status, cell membrane stability index, osmolytes, antioxidant enzymes, mineral nutrients, pod yield and some pod quality attributes of snap bean plants
| Irrigation |
GABA |
Significance |
|||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Variables | Well-watered | Water-deficit | LSD≤0.05 | 0 mM | 0.5 mM | 1 mM | 2 mM | LSD≤0.05 | Irrigation | GABA | Interaction |
| Shoot fresh weight (g. plant −1) | 156.3 A | 117.9 B | 3.95 | 124.3 B | 141.0 A | 140.2 A | 142.8 A | 5.59 | *** | *** | ns |
| Shoot dry weight (g. plant −1) | 29.2 A | 21.9 B | 0.64 | 23.7 C | 26.3 AB | 25.5 B | 26.6 A | 0.91 | *** | *** | ns |
| Leaf area (cm2.plant−1) | 1639 A | 1310 B | 39.3 | 1382 B | 1504 A | 1507 A | 1503 A | 55.6 | *** | *** | ns |
| RWC (%) | 85.7 A | 71.5 B | 0.77 | 76.7 B | 78.9 A | 78.8 A | 79.9 A | 1.09 | *** | *** | ns |
| CMSI (%) | 81.9 A | 72.8 B | 0.83 | 74.9 C | 76.9 B | 78.3 A | 79.1 A | 1.17 | *** | *** | ns |
| MDA (nmol.g−1 FW) | 7.38 B | 8.58 A | 0.30 | 8.26 A | 7.96 AB | 7.87 AB | 7.83 B | 0.42 | *** | ns | *** |
| Proline (µg.g−1 FW) | 193.8 B | 600.1 A | 22.8 | 335.5 C | 388.6 B | 428.7 A | 435.1 A | 32.2 | *** | *** | *** |
| FAA (µg.g−1 FW) | 552 B | 932 A | 46.3 | 622.4 C | 737.7 B | 818.7 A | 790.1 AB | 65.5 | *** | *** | * |
| Soluble sugars (mg.g−1 FW) | 2.80 B | 3.51 A | 0.08 | 2.88 B | 3.21 A | 3.24 A | 3.30 A | 0.11 | *** | *** | ns |
| SOD (∆ O.Dmin −1. mg −1 protein) | 6.59 B | 8.74 A | 0.37 | 6.80 C | 7.45 B | 8.09 A | 8.32 A | 0.52 | *** | *** | ns |
| CAT (∆ O.Dmin −1. mg −1 protein) | 1.89 B | 3.63 A | 0.20 | 2.49 C | 2.58 BC | 2.83 AB | 3.12 A | 0.29 | *** | *** | ** |
| POX (∆ O.Dmin −1. mg −1 protein) | 26.07 B | 42.39 A | 1.59 | 31.29 C | 33.87 B | 35.45 AB | 36.31 A | 2.26 | *** | *** | ns |
| APX (∆ O.Dmin −1. mg −1 protein) | 1.32 B | 2.28 A | 0.07 | 1.67 C | 1.77 BC | 1.85 AB | 1.89 A | 0.107 | *** | *** | * |
| N (%) | 3.38 A | 2.99 B | 0.12 | 3.05 B | 3.01 B | 3.18 B | 3.48 A | 0.18 | *** | *** | ns |
| P (%) | 0.537 A | 0.493 B | 0.017 | 0.504 B | 0.491 B | 0.514 B | 0.553 A | 0.024 | *** | *** | ns |
| K (%) | 3.09 A | 2.94 B | 0.125 | 2.90 BC | 2.84 C | 3.03 B | 3.29 A | 0.176 | * | *** | ns |
| Ca (%) | 1.71 A | 1.32 B | 0.07 | 1.26 B | 1.61 A | 1.58 A | 1.59 A | 0.104 | *** | *** | ns |
| Fe (ppm) | 185.2 A | 135.3 B | 10.7 | 155.3 B | 150.4 B | 162.3 AB | 173.1 A | 15.09 | *** | * | ns |
| Zn (ppm) | 64.9 A | 53.4 B | 5.1 | 58.3 AB | 55.3 B | 60.1 AB | 62.9 A | 7.23 | *** | ns | ns |
| Pod yield (ton.ha−1) | 11.98 A | 7.68 B | 0.28 | 8.74 C | 9.52 B | 10.39 A | 10.65 A | 0.40 | *** | *** | ns |
| Protein (g. 100 g−1 DW) | 18.96 A | 17.19 B | 0.81 | 16.26 C | 17.53 B | 19.08 A | 19.43 A | 1.15 | *** | *** | ns |
| Fibers (g. 100 g−1 DW) | 3.42 B | 4.18 A | 0.11 | 3.97 A | 3.81 B | 3.75 B | 3.67 B | 0.157 | *** | ** | ns |
| TSS | 4.41 A | 3.43 B | 0.14 | 3.61 C | 3.65 C | 4.09 B | 4.35 A | 0.20 | *** | *** | * |
| Data of the two seasons of 2018 and 2019 were subjected to combined analysis with 3 replicates in each season. The different capital letters within a row indicate significantly different values according to LSD’s multiple range tests (P ≤ 0.05).; RWC, leaf relative water content; MDA, malondialdehyde; CMSI, cell membrane stability index; FAA, free amino acids; SOD, superoxide dismutase; APX, ascorbate peroxidase; POX, peroxidase; CAT, catalase; TSS, total soluble solids. ns, not significant, * P ≤ 0.05, ** P ≤ 0.01 and *** P ≤ 0.001. | |||||||||||