Biological activity of humic substances and phenolic compounds extracted from two different forest soils of Aspromonte (Southern Italy)

The biological effects of humic substances and phenolic compounds on leaf explants of Nicotiana plumbaginifolia were compared to those of some growth regulators. The results show that the phenolic compounds are more effective on rooting of Nicotiana sp., while the humic substances increase the invertase levels interfering with gibberellic acid metabolism, suggesting that these compounds, characterized by a different chemical structure, could differently interact with membranous sites evoking a different response, in some case similar to those due to growth regulators.