Phytotoxic Substances in Runoff from Forested Catchment Areas

• Runoff from different catchment areas in southem Sweden was tested in a root bioassay based on solution cultures of cucumber seedlings. Water samples from agricultural catchment areas produced no signs at all or only weak signs of inhibited root growth, whereas several water samples from catchmcnt areas dominated by mires or coniferous forests produced visible root injuries. The most severe root injuries (very short roots, discolouration, swelling of root tips and lack of root hairs) were caused by samples from a catchment area without local emissions and dominated by old stands of spruce. Fractionation by ultrafiltration showed that the phytotoxic effect of these samples could be attributed to organic matter with a nominal molecular-weight  exceeding 1000 or to substances associated with organic macromolecules. Experiments aimed at concentrating phytotoxic compounds from surface water indicated that the observed growth  inhibition was caused by strongly hydrophilic substances. Previous reports on phytotoxic, organic substances of natura! origin have emphasized interaction between plants growing close together. The presence of phytotoxic substances in runoff indicates that there is also a large-scale dispersion of such compounds.

Ämnesord

LANTBRUKSVETENSKAPER  -- Annan lantbruksvetenskap -- Miljö- och naturvårdsvetenskap (hsv//swe)

AGRICULTURAL SCIENCES  -- Other Agricultural Sciences -- Environmental Sciences related to Agriculture and Land-use (hsv//eng)

NATURVETENSKAP  -- Kemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences (hsv//eng)

Nyckelord

Water Pollution

Publikations- och innehållstyp

ref (ämneskategori)

kap (ämneskategori)