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Title:The Effect of the Site of Nitrogen Assimilation on Plant Growth
Author(s):Lexa, Matej
Doctoral Committee Chair(s):Cheeseman, John M.
Degree Granting Institution:University of Illinois at Urbana-Champaign
Subject(s):Agriculture, Agronomy
Abstract:In this dissertation, I have explored this question experimentally. My approach was to obtain plants with NO3- reduction mostly in the roots or mostly in the leaves, measure growth and biomass allocation parameters of those plants when grown on NO3-, and compare them to growth of wild-type (WT) plants and nitrate reductase deficient mutants. Two techniques were used to manipulate the site of NO 3- reduction: (i) grafting and (ii) genetic transformation. Grafted wildtype and nitrate reductase-deficient pea plants adapted to changes in the location of NO3- reduction. The results support the idea of rapid mixing of metabolite pools and provide evidence for shoot to root signalling of nitrogen status. Utilizing tissue-specific promoters, plants were created with altered levels of nitrate reductase in roots and shoots. The results showed that transformation of WT plants with nia2 tobacco gene resulted in greater alterations in NRA than the transformation of the corresponding double mutant. Changes in growth and co-suppression-like leaf chlorosis was the most frequent outcome, often causing a lowering or disappearance of NRA. A negative correlation between the ratio of root and shoot reduction of nitrate and the root shoot ratio of transformed plants was found. The possible reasons for differences between the two approaches are discussed.
Issue Date:1999
Description:173 p.
Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1999.
Other Identifier(s):(MiAaPQ)AAI9921710
Date Available in IDEALS:2015-09-28
Date Deposited:1999

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