Developmental and Structural Section
Stevens, Kevin , Peterson, Larry .
Root system characteristics and plant response to flooding and drought: A comparison of morphological and anatomical responses of root systems of three Iris spp.
While it is known that hydrology influences wetland plant community structure, few predictive models of wetland plant community response to altered hydrological cycles exist. Identifying anatomical and morphological traits that confer an ability of root systems to function under extremes of water availability is precursory to the development and refinement of predictive models of wetland plant community responses to changing hydrological patterns. To further understand the relationship between root system characteristics and plant performance in wetland habitats, morphological and anatomical responses of root systems of three Iris spp (I. versicolor, I. virginica and I. pseudacorus) grown at one of three levels of availability; flooded, intermediate and dry were quantified and compared. Aboveground biomass and root biomass differed among species and treatments, but was consistently higher for I. pseudoacorus in all treatments. Rooting depth was significantly reduced in the flooded treatments. Shoot/root ratios were significantly lower in the intermediate treatment for I. virginica and I. versicolor but not I. pseudacorus. Tissue porosity increased with increasing water availability. Iris spp have a dimorphic root system consisting of adventitious roots and first order lateral roots. Anatomical responses differed among these two root types. Generally, first order laterals exhibited greater plasticity than adventitious roots. For many traits the relationship between the trait and performance did not agree with predicted relationships. The relationships were not consistent among species and were dependent on water availability. The difficulties of extrapolating plant tolerance to flooding and drought from terrestrial to wetland plant species is discussed.
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1 - University of North Texas, Department of Biological Sciences, Institute of Applied Sciences, Denton, TX, 76203, USA
2 - University of Guelph, Department of Molecular and Cellular Biology, Guelph, Ontario, N1G 2W1, Canada
Presentation Type: Oral Paper:Papers for Sections
Date: Tuesday, July 29th, 2008
Time: 4:15 PM