ABSTRACT
A number of researchers have suggested that tidal action and the effect of waterlogging play a significant role in determining the zonation of plant species in coastal salt marshes. Precise data are needed to sort out the various environmental effects that flooding may have on plants at different stages of plant development. One of the direct effects reported for flooding in salt marshes is a reduction in the level of aeration in the soil which could impede plant growth, since oxygen is necessary for aerobic respiration in roots. Laboratory experiments were initiated with salt marsh species from Portaferry marshes to determine the effects of salt stress and tidal inundation on salt marsh species. Growth of halophytes in inland marshes and upper portion of coastal marshes is more limited by waterlogging and tidal inundation than is that of lower marsh species, which have evolved under conditions of nearly daily tidal inundation.
