PARENT SESSION
Oral Session #17: Wetland Ecology. Presiding: E. Weiher.
Monday, August 6, 2001. 1:00 PM to 4:15 PM. Hall of Ideas H.
Effects of mycorrhizal inoculation on the growth of a perennial wetland grass.
Marx, Laura1,2, Fennessy, Siobhan1, 1 2
ABSTRACT- Research into the extent and ecological significance of arbuscular mycorrhizal (AM) infection in aquatic plants has been overlooked in favor of studies in terrestrial habitats. Field studies have documented mycorrhizal infection in wetland plants, even in flooded soils, but have not examined the effects of AM on their plant hosts. We tested the effect of mycorrhizal inoculation on Phalaris arundinacea, a perennial wetland grass, under controlled conditions. P. arundinacea was grown in three hydrologic treatements designed to approximate upland (unsaturated), wetland border (saturated), and flooded conditions, with and without mycorrhizal inoculation. Mycorrhizal inoculation (Glomus clarum, claroideum, intraradices, and etunicatum) resulted in significant infection under all hydrologic conditions. Plants inoculated with mycorrhizae had greater shoot biomass (p=0.024), root/shoot ratios (p=0.003), and shoot phosphorus concentrations (p=0.018) than did control plants. We conclude that inoculation under continuously flooded conditions can be a useful technique for creating or altering levels of AM infection, and that even under flooded soil conditions, AM infection increases the growth and nutrient uptake of P. arundinacea.
KEY WORDS: arbuscular mycorrhizae, aquatic plants, Phalaris arundinacea, wetland plant ecology