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Nitrate transport is independent of NADH and NAD(P)H nitrate reductases in barley seedlingsBarley (Hordeum vulgare L.) has NADH-specific and NAD(P)H-bispecific nitrate reductase isozymes. Four isogenic lines with different nitrate reductase isozyme combinations were used to determine the role of NADH and NAD(P)H nitrate reductases on nitrate transport and assimilation in barley seedlings. Both nitrate reductase isozymes were induced by nitrate and were required for maximum nitrate assimilation in barley seedlings. Genotypes lacking the NADH isozyme (Az12) or the NAD(P)H isozyme (Az70) assimilated 65 or 85%, respectively, as much nitrate as the wild type. Nitrate assimilation by genotype (Az12;Az70) which is deficient in both nitrate reductases, was only 13% of the wild type indicating that the NADH and NAD(P)H nitrate reductase isozymes are responsible for most of the nitrate reduction in barley seedlings. For all genotypes, nitrate assimilation rates in the dark were about 55% of the rates in light. Hypotheses that nitrate reductase has direct or indirect roles in nitrate uptake were not supported by this study. Induction of nitrate transporters and the kinetics of net nitrate uptake were the same for all four genotypes indicating that neither nitrate reductase isozyme has a direct role in nitrate uptake in barley seedlings.
Document ID
20040112069
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Warner, R. L.
(Washington State University Pullman 99164-6420, United States)
Huffaker, R. C.
Date Acquired
August 21, 2013
Publication Date
January 1, 1989
Publication Information
Publication: Plant physiology
Volume: 91
ISSN: 0032-0889
Subject Category
Life Sciences (General)
Funding Number(s)
CONTRACT_GRANT: DMB 85-05095
Distribution Limits
Public
Copyright
Other
Keywords
NASA Discipline Number 61-10
Non-NASA Center
NASA Discipline Life Support Systems
NASA Program CELSS

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