Seedling sulfide sensitivity among plant species colonizing Phragmites-infested wetlands

Abstract

Seedling establishment is an important means of re-colonizing herbicide-treated and burned Phragmites australis marshes and of filling in newly created or naturally forming marshes. Knowing the differential sensitivity of the various species to sulfide better enables us to predict which plants are likely to colonize given areas (i.e., be it desirable species or P. australis). This study focuses on the sulfide sensitivity of the seedlings of five plant species that may re-colonize the cleared marsh surface either from wild seed stock or introduced propagules: Spartina alterniflora, Spartina patens, Setaria magna, Atriplex triangularis, and P. australis. Seedlings were grown in culture tubes in semi-solid agar media containing Hoagland’s nutrients; sulfide treatments included levels of sulfide from 0 to 8 mM. Parameters measured included number of leaves, number of lateral roots, shoot length, root length, leaf length, and biomass. Setaria magna proved to be the most sensitive to sulfide, followed in order by A. triangularis, S. patens, P. australis, and S. alterniflora. Differences in edaphic sulfide are not likely to be helpful in favoring S. magna, A. triangularis, or S. patents over P. australis. Phragmites australis was compared to S. alterniflora in a second experiment with six concentrations of sulfide between 0 and 2.0 mM. Results indicated that sulfide levels between 0.4 and 0.9 mM would favor seedling establishment of S. alterniflora over P. australis, and at 0.9 mM, S. alterniflora seedlings would have the decided advantage.