Sulphide tolerance in coastal halophytes

Abstract

The effect of sulphide on the growth of several species of salt-marsh plants was investigated. Relative growth rates were significantly reduced in two upper-marsh species, Festuca rubra and Atriplexpatula, and in the lower-marsh species Puccinellia maritima. However the growth of Salicornia europaea, a species frequently associated with sulphide-containing sediments, was unaffected. In a separate experiment the wide ranging halophyte Aster tripolium, also appeared to be tolerant of sulphide at a concentration frequently encountered in salt marshes. Sulphide pretreatment inhibited the activity of two metallo-enzymes, polyphenol oxidase and external phosphatase, in plants from the upper marsh, but had no effect on enzymes from P. maritima or S. europaea. The rate of respiration by root tissue was significantly reduced in all of the species investigated but whereas the uptake of S6rubidium was markedly inhibited in the other three species, uptake by S. europaea showed a significant stimulation. Similarly, whereas sulphide-grown plants of F. rubra, A. patula and P. maritima had a considerably reduced tissue iron content, the total iron concentration in S. europaea tissues was comparable to that of the controls. When the sulphide-tolerant species A. tripolium was grown in sulphide-containing media there was no significant effect on the tissue concentration of any of the elements investigated. These results are discussed in relation to possible mechanisms of sulphide toxicity and resistance.

Mechanism for the hydrogen sulfide‐induced growth limitation in wetland macrophytes

“…These results support earlier findings that showed similar differences in sulfide tolerance between these two species (K0c.h and Mendelssohn 1989). Work with other wetland macrophytes has also shown differential tolerance of sulfide and coincidence of sensitivity with species distribution iin the field (Havill et al 1985).…”

“…A decrease in the activity of root metallo-enzymes has been postulated as the phytotoxic effect of HzS (Allam and Hollis 1972;Havill et al 1985;Pearson and Havill 1988) primarily because important oxidalses such as cytochrome oxidase -the terminal enzyme in the electron transport chain of aerobic respiration-are inhibited by sulfide. Wetland macrophytes growing in anoxrc, waterlogged soils, where H,S can accumulate often exhibit anoxic root metabolism., however, which is believed to contribute to energy production (e.g.…”

“…Although H,S is known to reduce growth in plants, we are only beginning to understand how this phytotoxin affects metabolic functions in marine, brackish, and freshwater wetland plant species. Under aerobic conditions in the root, sulfide can bind with metallo-enzymes (Allam and Hollis 1972;Havill et al 1985;Pearson and Havill 1988), reducing the respiratory capacity of the roots by denaturing important oxidases and lowering the potential for aerobic root energy production. The data presented here show that H,S can inhibit ADH activity, thereby limiting the functioning of an important alternate, anoxic pathway.…”

Reed die-back related to increased sulfide concentration in a coastal mire in eastern Hokkaido, Japan

“…Phragmites is able to protect itself to some extent by the diffusion of oxygen from its roots, which oxidizes the immediate area around the roots. Under anoxic conditions, phytotoxins such as sulfide (Havill et al 1985;F€ u urtig et al 1996;Lamers et al 1998) and organic acids (Armstrong et al 1996a;Armstrong and Armstrong 2001) can reach critical levels. Sulfide toxicity harms mostly the root system of the Phragmites plants (Fogli et al 2002).…”

Oxidation of sulfide by Spartina alterniflora roots

“…It is well established that sulfide can have deleterious effects (e.g., Howes et al 1986;Pearson and Havill 1988;Pezeshki et al 1993;Pezeshki and Delaune 1996). Environmental sulfide enters the root tissues (Carlson and Forrest 1982) and can inhibit metalloenzymes, including cytochrome c oxidase (Allam and Hollis 1972;Havill et al 1985). Sulfide exposure correlates with stunted growth in the field (King et al 1982) and results in reduced growth, alcohol dehydrogenase activity, adenylate charge, and nitrogen uptake in laboratory experiments (Koch and Mendelssohn 1989;Koch et al 1990).…”