RICKEY, MARCIA* and ROGER ANDERSON. Illinois State University, Biological Sciences Department, Campus Box 4120, Normal IL, 61790. - Characterization of three Phragmites australis sites and populations through soil analysis and photosynthesis measurements.
Phragmites australis is an invasive grass that has dramatically
increased its distribution and abundance within its geographic range
in the past fifty years. Sequence data show that Phragmites
native haplotypes “E” and “S” and invasive haplotype “M” exist in
North America. Three Illinois type M Phragmites sites and
populations were characterized by soil analysis and photosynthetic
measurements in this study: Banner, Lincoln, and Herrin. It was
hypothesized that there will be differences in soil variables among
sites and differences in maximum photosynthetic rates
(PMAX) rates among populations. MANOVA yielded significant
results (Wilks’ Lambda, F=5.67, p>F=0.0006) and univariate ANOVAs
indicated significant differences among sites for total nitrogen,
nitrate-nitrogen, organic matter, potassium, magnesium, and
phosphorus. The Ryan-Einot-Gabriel-Welsch (REGW) multiple range test
revealed that Banner Marsh was significantly lower than Lincoln and
Herrin for log K, P, SqRt total N, and log NO3-N.
Photosynthetic light response curves and PMAX, and light
saturation values were determined for plants from the three
populations. Plants had maximum photosynthetic rates of about 16 µmol
CO2 m-2s-1 and achieved light
saturation between 1200-1400 µmol m-2s-1 PPFD
(photosynthetically active photon flux density). ANOVA revealed
significant differences in PMAX rates among sites (F=38.14,
p<0.0001) and that Lincoln had the highest mean PMAX of
20.88.
Key words: photosynthesis, Phragmites australis, soil analysis