Phytotoxins in Periodically Waterlogged Forest Soils

Abstract

The concentration of iron(I1). manganese(I1). ethylene, volatile fatty acids (VFAs) and hydrogen sulphid have been determined in peaty forest soils subject to waterlogging. Although VFAs would merit further investigation, iron(I1) seems to be the only toxin likely to accumulate in sufficiently large quantities to cause root damage.The use of the ion selective electrode for sulphide measurements is criticized.

Compensatory growth of a submerged macrophyte (Vallisneria spiralis) in response to partial leaf removal: effects of sediment nutrient levels

“…Thus, we speculated that the low sediment density in the present experiment limited the plant growth. In addition, fertile sediments always contain a number of reduced chemical substances and various byproducts of anaerobic microbial metabolism, some of which may be phytotoxic and inhibit plant growth under anaerobic conditions (Sanderson and Armstrong 1980;Barko and Smart 1983). Though submersed macrophytes are reportedly capable of adapting anaerobic conditions to certain extent by transporting photosynthetically originated oxygen to their roots (Lorenzena et al 2001), this mechanism seems to be ineffective in fertile sediments (Carpenter et al 1983;Chen and Barko 1988).…”

THE RHIZOSPHERE ECOLOGY OF SUBMERSED MACROPHYTES1

“…Sediment is a very complex chemical and microbiological environment, even in the absence of plant roots. The tendency of sediment to develop anaerobic conditions, coupled with the presence of toxic constituents and/or oxygen-demanding materials (Ponnamperuma, 1972;Gunnison, et al, 1985), yield a substrate that places considerable stress on most macrophytes using this material as a rooting medium (Sculthorpe, 1967/ Sanderson andArmstrong, 1980). The stress can be increased by unfavorable physical properties (flocculence) that make certain sediments unsuitable media for some submersed macrophytes (Sculthorpe, 1967).…”