Date of Graduation

Summer 2008

Degree

Master of Science in Biology

Department

Biology

Committee Chair

D. Alexander Wait

Keywords

zizania aquatica, backwater lake, hydrology, physiological, tolerance

Subject Categories

Biology

Abstract

Records from the Illinois Natural History Survey of the late 1930s and early 1940s indicate that natural wild rice (Zizania aquatica L.var. aquatica) populations were common in backwater lakes throughout the Illinois River Valley; however, only a single population was documented in this region between 2001 and 2007. This single population, located in Spring Lake near Pekin, Illinois, provided seed for this study. After several seasons of trials to assess germination requirements, plugs were successfully produced in April, 2007; and were used for the present out-planting study. The purpose of this study was to determine the range of physiological tolerances of Z. aqatica var. aquatica to 19 water and soil variables, as it has not been previously studied in Z. aquatica L. var. aquatica populations from this particular region. One month old plugs of wild rice were planted at 15 different sites within the southern half of the Upper Mississippi River Valley during the 2007 growing season. Plants at all sites survived to reproductive stages with an average seed viability of 89.5%, although final plant height ranged from (180.4 cm to 378.7 cm). Interestingly, water and soil pH ranged widely across study sites (water: 5.6-11.1; soil: 5.0-7.8) but were not found to correlate with plant growth during any phenology stage. Due to the success of these plants across a wide and variable range of edaphic conditions, it is suspected that Z. aquatica L. var. aquatic maintains an extensive physiological tolerance range and therefore a narrow tolerance range does not explain the loss of naturally occurring populations in this region.

Copyright

© Bethany R. Dalrymple

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