Waterlogging Stress and Ethylene Production in the Dune Slack Plant,Scirpus americanus

Abstract

Seliskar, D. M. 1988. Waterlogging stress and ethylene production in the dune slack plant, Scirpus americanus.—J. exp. Bot. 39: 1639-1648. The sedge, Scirpus americanus Pers., grows in dune slacks and other freshwater and brackish water wetland communities. When waterlogged in a greenhouse, the concentration of ethylene increased 4-fold in stems of S. americanus plants. This increase was associated with a decrease in plant height and an increase in aerenchyma as exhibited under waterlogged conditions. Endogenous ethylene production in S. americanus was compared to that in another dune slack species, Panicum amarulum, and also to Spartina alterniflora from a salt marsh. These species did not respond by increasing endogenous ethylene upon waterlogging. In the field, a 16 cm rainfall significantly increased the endogenous ethylene production in S. americanus. As the water table subsided the concentration of accumulated ethylene in stem tissue decreased. Exposure of S. americanus to exogenous ethylene inhibited stem extension and increased aerenchyma formation, thus linking ethylene to the morphological characteristics of waterlogged plants of this species. These experiments support the hypothesis that ethylene modulates S. americanus morphology in natural waterlogged environments and may be of importance in adapting this species to life in the wetland environment.