Sulfide as a soil phytotoxin-a review.

Leon P M Lamers,Inge C J M Janssen,Marieke M Van Katwijk,Jan G M Roelofs,Tjisse Van Der Heide,Jeroen J M Geurts,Laura L Govers,Marlies E W Van Der Welle,Alfons J P Smolders

doi:10.3389/fpls.2013.00268

Abstract

In wetland soils and underwater sediments of marine, brackish and freshwater systems, the strong phytotoxin sulfide may accumulate as a result of microbial reduction of sulfate during anaerobiosis, its level depending on prevailing edaphic conditions. In this review, we compare an extensive body of literature on phytotoxic effects of this reduced sulfur compound in different ecosystem types, and review the effects of sulfide at multiple ecosystem levels: the ecophysiological functioning of individual plants, plant-microbe associations, and community effects including competition and facilitation interactions. Recent publications on multi-species interactions in the rhizosphere show even more complex mechanisms explaining sulfide resistance. It is concluded that sulfide is a potent phytotoxin, profoundly affecting plant fitness and ecosystem functioning in the full range of wetland types including coastal systems, and at several levels. Traditional toxicity testing including hydroponic approaches generally neglect rhizospheric effects, which makes it difficult to extrapolate results to real ecosystem processes. To explain the differential effects of sulfide at the different organizational levels, profound knowledge about the biogeochemical, plant physiological and ecological rhizosphere processes is vital. This information is even more important, as anthropogenic inputs of sulfur into freshwater ecosystems and organic loads into freshwater and marine systems are still much higher than natural levels, and are steeply increasing in Asia. In addition, higher temperatures as a result of global climate change may lead to higher sulfide production rates in shallow waters.

Highlights

ANAEROBIOSIS AND SOIL SULFUR TRANSFORMATIONS sulfur (S) is one of the six macronutrients for plant growth and low availability of S may limit primary production (Marschner, 1995; Leustek and Saito, 1999), the accumulation of reduced sulfur in sediments of aquatic systems and permanent or riparian wetlands generally causes physiological toxicity stress for the community involved, including its plants, animals and micro-organisms (Bagarinao, 1992)
Unlike the first billion years of life on earth, when sulfide oxidation was an integral part of life generating energy, sulfide accumulation has become much less common as a result of biogenic oxygen production, and sulfide has become toxic to many organisms inhabiting the top layer of soils, including plants (Olsen, 2012)
SULFUR UPTAKE AND INTERNAL DETOXIFICATION Sulfur concentrations in shoots of terrestrial plants are, on average 30 μmol g−1 (Gruhlke and Slusarenko, 2012), but values may be higher for freshwater wetland plants (35–150 μmol g−1, Van der Welle et al, 2007a,b) and marine plants (100–400 μmol g−1; Holmer and Kendrick, 2013), most probably related to the level of S availability in the different environments, but possibly as a result of the presence of sulfides in the soil

Summary

Introduction

ANAEROBIOSIS AND SOIL SULFUR TRANSFORMATIONS sulfur (S) is one of the six macronutrients for plant growth and low availability of S may limit primary production (Marschner, 1995; Leustek and Saito, 1999), the accumulation of reduced sulfur in sediments of aquatic systems and permanent or riparian wetlands (including estuarine and marine) generally causes physiological toxicity stress for the community involved, including its plants, animals and micro-organisms (Bagarinao, 1992). SULFUR UPTAKE AND INTERNAL DETOXIFICATION Sulfur concentrations in shoots of terrestrial plants are, on average 30 μmol g−1 (Gruhlke and Slusarenko, 2012), but values may be higher for freshwater wetland plants (35–150 μmol g−1, Van der Welle et al, 2007a,b) and marine plants (100–400 μmol g−1; Holmer and Kendrick, 2013), most probably related to the level of S availability in the different environments, but possibly as a result of the presence of sulfides in the soil.

Results

Conclusion