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Abstract Detail



Ecophysiology

Smart , Cera M [1], Kramer, Diedre [1], Caudle, Keri L. [2], Hilt , Christina J [3], Cheema, Sana [1], Johnson, Loretta [4], Baer, Sara [5], Maricle, Brian [6].

Nitrate reductase activities in big bluestem (Andropogon gerardii) ecotypes.

Nitrogen is one of the essential nutrients for plant growth, and is most commonly taken up in the form of nitrate. Reduction of nitrate to nitrite, catalyzed by the enzyme nitrate reductase, is the first step in converting inorganic nitrogen into organic nitrogen during assimilation. Following assimilation, nitrogen is used in proteins, nucleic acids, chlorophyll, and osmolytes, which can vary according to systematic or environmental differences. For example, drought tolerance in prairie grasses seems to be related to nitrogen, as drought adapted species have more nitrogen compared to more mesic plants. Moreover, nitrogen is correlated with differences in drought tolerance within a species, and ecotypic (intraspecific) variation provides opportunities to study evolution of drought tolerance mechanisms. It was hypothesized the drought tolerance in ecotypes of big bluestem (Andropogon gerardii) is related to assimilation of inorganic nitrogen. Leaves were collected from five ecotypes of big bluestem from four common gardens across a 1150 kilometer precipitation gradient. Differences occurred in nitrate reductase activities between sites and ecotypes. Nitrate reductase activities were highest at the driest common garden sites in Hays and Colby, Kansas. The Illinois ecotype, adapted to abundant rainfall, had higher nitrate reductase activities compared to some other ecotypes. Nitrate reductase activity appears to be an environmentally induced response to dry conditions, and not due to genetic difference between ecotypes. Ecotypic differences in nitrogen content are the result of processes other than nitrate assimilation.   


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1 - Fort Hays State University , Department of Biological Sciences , 600 Park Street, Hays, KS, 67601, USA
2 - Fort Hays State University, Department of Biological Sciences, 600 Park St., Hays, KS, 67601, USA
3 - Fort Hays State University, Department of Biological Sciences, 600 Park St, Hays , Kansas, 67601, USA
4 - Kanas State University, Division of Biology, Ackert Hall, Manhattan, KS, 66506, United States
5 - Southern Illinois University, Department of Plant Biology and Center for Ecology , 1000 Faner Dr, Carbondale, IL, 62901, USA
6 - Fort Hays State University, Department Of Biological Sciences, 600 Park St., Hays, KS, 67601-4099, USA

Keywords:
big bluestem
sand bluestem
ecotype
Nitrate Reductase
Nitrogen Assimilation
drought tolerance.

Presentation Type: Poster:Posters for Topics
Session: P
Location: Eyrie/Boise Centre
Date: Monday, July 28th, 2014
Time: 5:30 PM
Number: PEP008
Abstract ID:601
Candidate for Awards:Physiological Section Best poster presentation,Physiological Section Physiological Section Li-COR Prize


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