Caudle, Keri , Adler, Peter , Maricle, Brian .
Influence of water availability on photosynthesis, water potential, and phenology in Kansas grasses.
Mixed grass prairie is the zone where tallgrass prairies of the east intermingle with shortgrass prairies of the west. This shift is driven by precipitation, but very little is known regarding how dominant grasses respond to water availability. Andropogon gerardii, Bouteloua curtipendula, Schizachyrium scoparium, and Sorghastrum nutans were measured in three water treatments (ambient rainfall, drought, irrigated) at field sites of southern mixed grass prairie near Hays, KS. Photosynthesis and water potential were measured monthly in June and July of 2010 and 2011. Phenology and height measurements were collected semi-monthly in June, July, and August 2011.Growth increased under irrigated treatments in all four species. The highest photosynthesis rates were measured in irrigated S. nutans, but S. nutans was the most impacted by drought. No individuals of S. nutans remained in drought treatments by August 2011, water potentials were significantly higher than in other species, and individuals of S. nutans only reached reproductive stage in irrigated treatments. The most drought tolerant species were B. curtipendula and S. scoparium, as indicated by lower water potentials and an ability to maintain higher stomatal conductance and photosynthesis with low water availability. Moreover, individuals of B.curtipendula and S. scoparium reached reproductive stage in ambient and irrigated treatments. Andropogon gerardii had intermediate drought tolerance, as indicated by intermediate photosynthesis and water potential, and individuals only reaching reproductive stage in irrigated treatments. Studying physiological and ecological responses of dominant native grasses under decreased water availability can help us understand how drought might affect native grasses.
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1 - Fort Hays State University, Department of Biological Sciences, 600 Park Street, Hays, KS, 67601, USA
2 - Utah State University, Department of Wildland Resources and the Ecology Center, 5230 Old Main, Logan, UT, 84322-5230, USA
3 - Fort Hays State University, Department Of Biological Sciences, 600 Park St., Hays, KS, 67601-4099, USA
Presentation Type: Oral Paper:Papers for Topics
Date: Tuesday, July 10th, 2012
Time: 10:15 AM