Table 3.
Predictive importance (i) of chemical and biochemical variables to hormone-like (IAA-like, GA-like, IPA-like) activity of humic substances by Automatic Linear Modeling.
| Target variable | ||||||||
|---|---|---|---|---|---|---|---|---|
| IAA-like | GA-like | IPA-like | ||||||
| Predictor | i | p value | Predictor | i | p value | Predictor | i | p value |
| N | 0.442 | 0.000 | SO42- | 0.475 | 0.000 | Mg | −0.368 | 0.000 |
| OAS-s | 0.292 | 0.000 | Carboxyl-C | 0.339 | 0.000 | Peptidic-C | −0.284 | 0.000 |
| S | 0.175 | 0.000 | OAS-s | −0.163 | 0.001 | O | −0.251 | 0.000 |
| IAA | 0.042 | 0.002 | Peptidic-C | −0.024 | 0.109 | Cys | 0.079 | 0.000 |
| Phenolic-OH | 0.020 | 0.016 | Fe | 0.009 | 0.017 | |||
| Ile | 0.016 | 0.027 | Phenolic-C | 0.009 | 0.021 | |||
| O | 0.013 | 0.045 | ||||||
Carboxyl-C, Carboxyl-C in HS by NMR; Cys, cysteine content in plants roots; Fe, iron content in plants roots; IAA, indoleacetic acid content in HS by ELISA; Ile, isoleucine content in plants roots; Mg, magnesium content in plants roots; N, nitrogen in HS by elemental composition; O, oxygen in HS by elemental composition; OAS-s, O-acetylserine sulphydrylase activity in plants roots; Peptidic-C, Peptidic-C in HS by NMR; Phenolic-C, Phenolic-C in HS by NMR; Phenolic-OH, Phenolic-OH acidity in HS by titration; S, sulfur in HS by elemental composition; SO4 2−, sulfate content in plants root.