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dc.contributor.author Macduff, James H.
dc.contributor.author Thornton, B.
dc.date.accessioned 2009-12-15T16:24:02Z
dc.date.available 2009-12-15T16:24:02Z
dc.date.issued 2002
dc.identifier.citation Macduff , J H & Thornton , B 2002 , ' Short-term changes in xylem N compounds in Lolium perenne following defoliation ' Annals of Botany , pp. 715-722 . , 10.1093/aob/mcf132 en
dc.identifier.issn 1095-8290
dc.identifier.other PURE: 132278
dc.identifier.other dspace: 2160/3835
dc.identifier.uri http://hdl.handle.net/2160/3835
dc.description Thornton, B., Macduff, J. H. (2002). Short-term changes in xylem N compounds in Lolium perenne following defoliation. Annals of Botany, 89, 715-722. Amino acids, defoliation, diurnal variation, flowing solution culture, Lolium perenne, nitrate uptake, perennial ryegrass, xylem exudate. Sponsorship: SEERAD / BBSRC en
dc.description.abstract Previous studies have indicated that an increased asparagine to glutamine ratio (Asn : Gln) occurs in the xylem fluid of Lolium perenne 24 h after defoliation. However, the absolute changes in Asn and Gln leading to the increased Asn : Gln ratio are unknown. The present study tested the hypotheses that: (1) defoliation-induced changes in xylem amino acid composition occur in L. perenne within the first 24 h following defoliation, irrespective of phasing with respect to the diurnal light/dark cycle; and (2) the increase in Asn : Gln ratio in the xylem fluid of L. perenne following defoliation is due to an increase in Asn content. Plants of L. perenne L. ‘Aurora’ were grown in flowing solution culture for 40 d. Plants were then either left intact, defoliated at the end of the light period or defoliated at the end of the dark period. 15N-labelled NO3– was supplied following defoliation to discriminate between the recovery of N absorbed prior to, and following, defoliation. Xylem samples were collected over the subsequent 24 h period with amino acids speciated by GC-MS. There was support for the first hypothesis: increased Asn : Gln ratios occurred within the first 24 h, irrespective of the phasing of defoliation with respect to light/dark cycles. The second hypothesis was not supported: the concentration of all amino acids in the xylem exudate declined after defoliation, and the increased Asn : Gln ratio was accounted for by a disproportionately large reduction in Gln levels. Low concentrations of amino acids in the xylem of defoliated plants precluded accurate discrimination of their nitrogen content into pre- and post-defoliation sources. en
dc.format.extent 8 en
dc.language.iso eng
dc.relation.ispartof Annals of Botany en
dc.title Short-term changes in xylem N compounds in Lolium perenne following defoliation en
dc.type Text en
dc.type.publicationtype Article (Journal) en
dc.identifier.doi http://dx.doi.org/10.1093/aob/mcf132
dc.contributor.institution Institute of Biological, Environmental and Rural Sciences en
dc.description.status Peer reviewed en


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