POPULATION VARIATION IN GROWTH-RESPONSE TO FLOODING OF 3 MARSH GRASSES

Comparative studies were conducted to evaluate intraspecific variation in leaf elongation and biomass partitioning in response to flooding s tress in populations of Spartina alterniflora a, S. patens, and Panicu m 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 abov e the soil surface for approximately 2 months and leaf elongation rate s, soil redox potentials, and final biomass of each population were me asured. Tests of flooding response between the populations indicated s ignificant ecotypic differentiation in biomass partitioning. Using a r otated principal components analysis, we identified the three most flo od tolerant and the three least flood tolerant populations for each sp ecies, with greater below-ground and below-water biomass or total biom ass production characterizing greater flood tolerance. The ability to select more flood tolerant populations has direct application in wetla nd creation and restoration. (C) 1997 Elsevier Science B.V.