Metabolism of Ammonium Ion and Glutamate in Relation to Nitrogen Supply and Utilization during Grain Development in Barley
Author(s) -
C. M. Duffus,
Roberta Rosie
Publication year - 1978
Publication title -
plant physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.554
H-Index - 312
eISSN - 1532-2548
pISSN - 0032-0889
DOI - 10.1104/pp.61.4.570
Subject(s) - endosperm , glutamate dehydrogenase , glutamine synthetase , ammonium , anthesis , glutamate receptor , glutamate synthase , biochemistry , transaminase , metabolism , glutamine , hordeum vulgare , biology , enzyme , chemistry , botany , amino acid , poaceae , receptor , organic chemistry , cultivar
Changes in the activity of a number of enzymes concerned with amino acid synthesis and metabolism were recorded for the endosperm, testa pericarp, and embryo of developing barley (Hordeum distichum L.) grains. Both glutamate-pyruvate transaminase and glutamate-oxaloacetate transaminase activities were present in all tissues and at all ages examined. Glutamate dehydrogenase activity was largely confined to endosperm while glutamine synthetase activity was mainly in the testa pericarp.Ammonium ion concentration was maximal in endosperm by 20 days after anthesis. Glutamate concentration varied in endosperm and was in the range of 3.5 to 8.5 mm between 20 and 45 days after anthesis. Significant levels of ammonium ion and glutamate were also present in the testa pericarp over the major part of the developmental period.
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