Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
347
pubmed:dateCreated
2000-11-13
pubmed:abstractText
35S-sulphate was flap-fed to poplar leaves of different leaf development stages - young developing, expanding, mature, and old mature poplar leaves. (35)S-sulphate was taken up independent of the leaf development stage. Whereas young development leaves did not export the (35)S taken up, export increased with increasing leaf development stage. Expanding leaves allocated the exported (35)S mainly into apical tree parts (73-87%) and only to a minor extent (13-27%) in basipetal direction. Neither lower trunk sections nor the roots were sinks for the exported (35)S. Expanding and developing leaves, but not the shoot apex, were the main sinks for the (35)S allocated in apical direction. In contrast, mature and old mature leaves exported the (35)S taken up mainly in basipetal direction (65-82%) with the roots constituting the main sinks. The (35)S allocated into apical tree parts was found in expanding and developing leaves, but only to a minor extent in the shoot apex. Apical allocated (35)S was identified as sulphate. Apparently the demand of young developing leaves for reduced sulphur was not fulfilled by mature leaves. Therefore, reduced sulphur for growth and development of young developing leaves must be supplied from other sources. In vitro activity of enzymes involved in assimilatory sulphate reduction was measured to investigate whether demand for reduced sulphur by young leaves is met by their own sulphate reduction. ATP sulphurylase and APS reductase activities were not significantly lower in developing than in mature leaves. Sulphite reductase and serine acetyltransferase activities were highest in developing leaves; O:-acetylserine (thiol) lyase activity was similar in all leaf developing stages. Apparently, young developing poplar leaves are able to produce their own reduced sulphur for growth and development. Whether other sources such as storage tissues and/or roots are involved in reduced sulphur supply to developing leaves remains to be elucidated.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
0022-0957
pubmed:author
pubmed:issnType
Print
pubmed:volume
51
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1077-88
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2000
pubmed:articleTitle
Leaf age-dependent differences in sulphur assimilation and allocation in poplar (Populus tremula x P. alba) leaves.
pubmed:affiliation
Albert-Ludwigs-Universität Freiburg, Institut für Forstbotanik und Baumphysiologie, Professur für Baumphysiologie, Am Flughafen 17, D-79085 Freiburg i.B., Germany.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't