Biological activity of humic substances extracted from soils under different vegetation cover

Biological Activities of Humic Substances

“…A further support to the hypothesis of an IAA -like action of HS is reported in Nardi et al (1999) . In this paper, comparisons were made between the chemical compositions of humic substances extracted from three soils covered by different vegetation and their biological activities assayed using 15 -and 30 -day -old seedlings of Pinus sylvestris and Picea abies .…”

Effect of Phosphorus Level and Some Growth Regulators on Productivity of Faba Bean (Vicia Faba L.)

“…The increase in vegetative growth characters by spraying humic acid on plant growth could be referred to its acting as source of plant growth hormones (Nardi et al, 1999). Afifi et al (2010) indicated that foliar application with humic acid improved nutrient status and promoted growth and yield components of faba bean plants.…”

Growth and development of pepper are affected by humic substances derived from composted sludge

“…Nevertheless, it must be taken into account that the presence of these compounds could not be completely discarded based only on the analytical method employed in the present work. Concerning the hormon-like activity of humic extracts, Nardi et al, (1999Nardi et al, ( , 2000 proposed that humic substances may evoke an auxin-like effect due to the interaction between their chemical structure and functional groups (phenolic and carboxylic) with hormone-binding proteins in the membrane systems. The auxinic activity of humic substances has been demonstrated in recent studies using a combination of genetic and molecular approaches (Trevisan et al, 2010b).…”