Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
2010-6-29
pubmed:abstractText
The rate of net CO(2) assimilation (A), the stomatal (g(s)) and residual (g(r)) conductances to CO(2), the intercellular CO(2) concentration, the CO(2) compensation points at 21% O(2) (Gamma(21)) and at 2% O(2) (Gamma(2)), and the amounts of dry matter, nitrogen, and carbohydrates were determined, from anthesis through grain filling, in the flag leaf blade and sheath of spring wheat (Triticum aestivum L. cv Kolibri). The nitrogen content and the rate of net CO(2) assimilation declined slowly until the onset of senescence in both organs, about 3 weeks after anthesis. During senescence the reduction of A in both organs was not primarily caused by a decrease in g(s); the main factor is the decrease in g(r). From values of Gamma(21) and Gamma(2) it is suggested that the rate of respiration in the light contributing to the CO(2) compensation point is higher in sheaths than in blades irrespective of the O(2) level considered. The role of sheaths storing and later transporting assimilates to the developing grains seems to be more important for shoot yield than that of sheaths functioning as photosynthetic organs after the onset of senescence occurs. It is suggested that accumulation of carbohydrates in leaves might somehow trigger senescence in the flag leaf blade and sheath simultaneously.
pubmed:commentsCorrections
pubmed:language
eng
pubmed:journal
pubmed:status
PubMed-not-MEDLINE
pubmed:month
Nov
pubmed:issn
0032-0889
pubmed:author
pubmed:issnType
Print
pubmed:volume
85
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
667-73
pubmed:dateRevised
2010-9-15
pubmed:year
1987
pubmed:articleTitle
Photosynthetic Gas Exchange Characteristics of Wheat Flag Leaf Blades and Sheaths during Grain Filling: The Case of a Spring Crop Grown under Mediterranean Climate Conditions.
pubmed:affiliation
Departament de Biologia Vegetal, Facultat de Biologia, Universitat de Barcelona, Diagonal 645, Barcelona 08028, Spain.
pubmed:publicationType
Journal Article