Table 3c.
Plant growth promoting substances secreted by phosphate solubilizing (PSB) isolates recovered from various rhizospheres.
| Strains | Plant growth promoting (PGP) substances | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| IAA (μgmL−1) | Siderophore | EPS(μgmL−1) | ACC deaminase activity (μM α-ketobutyrate mg−1 protein hour−1) | NH3 | HCN | ||||||||
| 0T* | 100T* | 200T* | 400T* | 500T* | FeCl3test | Halo size (mm) | SA (μgmL−1) | 2, 3-DHBA (μgmL−1) | |||||
| PSB1 | 42.3a ± 2.3 | 81.6a ± 3.2 | 88.2a ± 5.2 | 96.2a ± 5.6 | 114a ± 6.0 | ++ | 16.3a ± 0.5 | 39.3a ± 2.6 | 26.2a ± 2.0 | 29.4a ± 0.7 | 69.3a ± 5.8 | ++ | + |
| PSB2 | – | – | – | – | – | ++ | 15.0b ± 1.0 | 33.7b ± 1.5 | 18.7c ± 0.6 | – | 42.1b ± 4.3 | ++ | – |
| PSB3 | 26.4c ± 1.0 | 28.6d ± 1.3 | 32.8d ± 1.5 | 37.5f ± 1.8 | 48.6e ± 2.2 | ++ | – | – | – | – | 36.0c ± 2.5 | ++ | – |
| PSB4 | 13.3f ± 1.5 | 16.8 g ± 2.0 | 29.8e ± 5.2 | 42.3f ± 6.2 | 72.5b ± 7.2 | ++ | 13.0c ± 1.0 | 27.4c ± 1.6 | 15.6d ± 1.5 | – | – | ++ | – |
| PSB5 | – | – | – | – | – | ++ | – | – | – | – | – | ++ | – |
| PSB6 | 15.3e ± 1.5 | 19.8f ± 2.0 | 28.8e ± 5.2 | 38.3f ± 6.2 | 62.5c ± 7.2 | ++ | 16.0a ± 2.5 | 32.6b ± 2.0 | 14.3d ± 2.0 | – | 44.0b ± 3.6 | ++ | + |
| PSB7 | 27.1c ± 1.3 | 39.7b ± 1.4 | 50.6b ± 1.8 | 66.2b ± 2.3 | 73.1b ± 3.2 | ++ | – | – | – | 15.0d ± 2.3 | 29.4d ± 2.6 | ++ | – |
| PSB8 | – | – | – | – | – | ++ | 13.0c ± 1.0 | 17.6f ± 1.7 | 8.7f ± 0.4 | – | 37.2c ± 4.1 | ++ | + |
| PSB9 | 25.5c ± 1.0 | 39.6b ± 1.3 | 43.8c ± 1.5 | 49.5e ± 2.0 | 59.7c ± 3.0 | ++ | 12.0d ± 0.5 | 21.6e ± 1.5 | 10.3e ± 0.5 | – | – | ++ | + |
| PSB10 | 37.9b ± 1.0 | 42.3b ± 1.5 | 52.4b ± 2.1 | 59.3c ± 2.6 | 64.2c ± 4.0 | ++ | – | – | – | – | – | ++ | – |
| PSB11 | – | – | – | – | – | ++ | 15.0b ± 1.0 | 25.3c ± 1.5 | 21.3b ± 2.0 | 22.0 c ± 1.5 | 23.5e ± 1.2 | ++ | + |
| PSB12 | 16.1e ± 0.6 | 21.5e ± 0.9 | 33.4d ± 1.3 | 51.2d ± 1.9 | 58.3c ± 3.4 | ++ | 13.0c ± 1.2 | 23.3d ± 0.5 | 16.0d ± 1.0 | 25.6b ± 2.3 | – | ++ | + |
| PSB13 | 22.8d ± 1.2 | 35.1c ± 1.5 | 42.0c ± 1.9 | 59.4c ± 2.6 | 75.2b ± 3.5 | ++ | – | – | – | 20.0c ± 1.0 | – | ++ | – |
| PSB14 | 13.7f ± 1.9 | 15.5 g ± 2.3 | 20.0f ± 2.6 | 35.1 g ± 3.1 | 49.2e ± 4.2 | ++ | 14.0b ± 0.5 | 23.6d ± 2.5 | 14.3d ± 0.5 | – | 18.2f ± 2.4 | ++ | – |
| PSB15 | 23.2d ± 2.0 | 37.4c ± 3.0 | 44.0c ± 3.5 | 53.0d ± 3.6 | 56.3d ± 4.0 | ++ | – | – | – | – | 16.2f ± 1.8 | ++ | – |
Values in this and subsequent tables indicate mean ± S.D. of three independent replicates. Means followed by alphabets a, b, c, d and e etc. are significantly different from each other according to Duncuan's multiple range (DMRT) test. Here, IAA = indole-3-acetic acid, CAS = Chrome Azurol S agar, SA = Salicylic acid, DHBA = 2, 3 Dihydroxybenzoic acid, ACC = 1-Amino cyclopropane 1-carboxylate, NH3; = Ammonia, HCN = Hydrogen cyanide and T = Tryptophan concentration (μg mL−1), symbols ‘+’ and ‘–’ indicate positive and negative reactions, respectively.