Population variation in growth response to flooding of three marsh grasses

Comparative studies were conducted to evaluate intraspecific variation in leaf elongation and biomass partitioning in response to flooding stress in populations of Spartina alterniflora a, S. patens, and Panicum hemitomon. These populations were collected along the Louisiana and Texas coasts and grown for four to six vegetative propagations in the greenhouse. Plants were flooded to a maximum water level of 39 cm above the soil surface for approximately 2 months and leaf elongation rates, soil redox potentials, and final biomass of each population were measured. Tests of flooding response between the populations indicated significant ecotypic differentiation in biomass partitioning. Using a rotated principal components analysis, we identified the three most flood tolerant and the three least flood tolerant populations for each species, with greater below-ground and below-water biomass or total biomass production characterizing greater flood tolerance. The ability to select more flood tolerant populations has direct application in wetland creation and restoration. (C) 1997 Elsevier Science B.V.