Table 2.
Indoleacetic acid (IAA) content and hormone-like activity (†) of total humic extracts (THE), high molecular size (HMS) and low molecular size (LMS) humic substances extracted from soil (1) (with Pinus mugo cover) and (2) (with Pinus sylvestris cover).
| HS | IAA | IAA-like | GA-like | IPA-like |
|---|---|---|---|---|
| % (w/w) | mg L−1 ≅ 1 mg C L−1 | |||
| THE1 | 0.01e* | 0.14d | 0.01e | 0.25d |
| HMS1 | 0.03d | 0.25d | 0.04d | 0.45b |
| LMS1 | 0.12b | 1.67b | 0.15b | 0.84a |
| THE2 | 0.03d | 0.72c | 0.01e | 0.12e |
| HMS2 | 0.05c | 0.91c | 0.07c | 0.35c |
| LMS2 | 0.35a | 5.25a | 0.21a | 0.79a |
†Concentration (mg L−1) of indoleacetic acid (IAA) or gibberellic acid (GA) or isopentenyladenosine (IPA) of equivalent activity as 1 mg C L−1 humic substances.
*Values within column followed by the same label are not statistically different at p = 0.05 by Student-Newman-Keuls (Sokal and Rohlf, 1969).