Permeability of plant tissues to humic acids

Abstract

When small branches of different plants were dipped after cutting into a solution of humic acid, a brown substance penetrated into vessels and coagulated there. The vascular bundles were stained to the height of 1–6 cm after a week. The presence of the humic acid in the parenchymal cells could not be demonstrated directly, but cells with a yellow or brown cell wall remained alive (they could be plasmolysed). Humic acid, labelled with C14 was distributed in the same way in sterile and in non-sterile plant cultures, mainly through vascular bundles.