Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
2010-6-29
pubmed:abstractText
The CO(2)-exchange rate required to make full use of available N(2)-fixation capacity, measured as acetylene reduction, was determined in soybean and alfalfa. Carbohydrates of root systems were depleted during a 40-hour dark treatment; then plants were exposed to a 24-hour light period during which different CO(2)-exchange rates were maintained with various CO(2) concentrations. In three- and four-week-old soybeans and four-week-old alfalfa plants, acetylene-reduction capacity was used fully with CO(2)-exchange rates as low as 10 milligrams CO(2) per plant per hour. In six-week-old alfalfa plants, however, acetylene reduction rates increased linearly, and apparent N(2)-fixation capacity was not used fully when CO(2)-exchange rates were higher than 40 milligrams CO(2) per plant per hour. Under the conditions established, the energy cost of N(2) fixation, measured as Delta(respiration of roots + nodules)/Deltaacetylene reduction over dark-treatment values, was 0.453 milligrams CO(2) per micromole C(2)H(4) for all rates of acetylene reduction and for both ages of soybean and alfalfa plants. Thus, root-plus-nodule respiration was not promoted by higher rates of apparent photosynthesis after C(2)H(2)-reduction capacity became saturated, and all available capacity for apparent N(2) fixation had the same energy requirement.
pubmed:commentsCorrections
pubmed:language
eng
pubmed:journal
pubmed:status
PubMed-not-MEDLINE
pubmed:month
Jul
pubmed:issn
0032-0889
pubmed:author
pubmed:issnType
Print
pubmed:volume
66
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
101-4
pubmed:dateRevised
2010-9-15
pubmed:year
1980
pubmed:articleTitle
Carbon exchange rates of shoots required to utilize available acetylene reduction capacity in soybean and alfalfa root nodules.
pubmed:affiliation
Department of Agronomy and Range Science, University of California, Davis, California 95616.
pubmed:publicationType
Journal Article