title: Chemical variation in Jacobaea vulgaris is influenced by the interaction of season and vegetation successional stage.
abstract: Knowledge on spatio-temporal dynamics of plant primary and secondary chemistry under natural conditions is important to assess how plant defence varies in real field conditions. Plant primary and secondary chemistry is known to vary with both season and vegetation successional stage, however, in few studies these two sources of variation have been examined in combination. Here we examine variations in primary and secondary chemistry of Jacobaea vulgaris (Asteraceae) throughout the growing season in early, mid, and late stages of secondary succession following land abandonment using a well-established chronosequence in The Netherlands. We investigated primary and secondary chemistry of both leaves and flowers, in order to determine if patterns during seasonal (phenological) development may differ among successional stages. The chemical concentration of primary and secondary chemistry compounds in J. vulgaris varied throughout the season and was affected by vegetation succession stage. Concentrations of pyrrolizidine alkaloid (PA) tertiary-amines were highest in flowers during early Summer and in fields that had been abandoned ten to twenty years ago. PA N-oxide concentrations of both leaves and flowers, on the other hand increased with the progression of both season and succession. In Spring and early Summer chlorophyll concentrations were highest, especially in the oldest fields of the chronosequence. During phenological development, nitrogen concentration increased in flowers and decreased in leaves revealing allocation of nutrients from vegetative to reproductive plant parts throughout the growing season. The highest concentrations of N-oxides and chlorophylls were detected in older fields. Thus, our results suggest that variations in plant patterns of nutritional and defence compounds throughout the growing season are depending on successional context.
authors.affiliation: Dept. of Terrestrial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), PO Box 50, 6700 AB Wageningen, The Netherlands; Dept. Natural Resources, ITC Faculty, University of Twente, PO Box 6, 7500 AA Enschede, The Netherlands. Electronic address: s.carvalho@nioo.knaw.nl.
authors.forename: Sabrina
authors.initials: S
authors.lastname: Carvalho
authors.affiliation: Dept. of Plant Ecology, Institute for Evolution and Ecology, University of Tuebingen, Auf der Morgenstelle 3, 72076 Tuebingen, Germany.
authors.forename: Mirka
authors.initials: M
authors.lastname: Macel
authors.affiliation: RIKILT-Institute of Food Safety, Wageningen University and Research Centre, PO Box 30, 6700 AE Wageningen, The Netherlands.
authors.forename: Patrick P J
authors.initials: PP
authors.lastname: Mulder
authors.affiliation: Dept. Natural Resources, ITC Faculty, University of Twente, PO Box 6, 7500 AA Enschede, The Netherlands.
authors.forename: Andrew
authors.initials: A
authors.lastname: Skidmore
authors.affiliation: Dept. of Terrestrial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), PO Box 50, 6700 AB Wageningen, The Netherlands; Laboratory of Nematology, Wageningen University, PO Box 8123, 6700 ES Wageningen, The Netherlands.
authors.forename: Wim H
authors.initials: WH
authors.lastname: van der Putten
mesh_terms: D000588:Amines / Q000032:analysis; D019659:Asteraceae / Q000737:chemistry* / Q000254:growth & development* / Q000378:metabolism; D002734:Chlorophyll / Q000032:analysis; D035264:Flowers / Q000737:chemistry / Q000254:growth & development; D009584:Nitrogen / Q000032:analysis; D010087:Oxides / Q000032:analysis; D018515:Plant Leaves / Q000737:chemistry / Q000254:growth & development; D011763:Pyrrolizidine Alkaloids / Q000032:analysis; D012621:Seasons
chemical_list: D000588:Amines; D010087:Oxides; D011763:Pyrrolizidine Alkaloids; D002734:Chlorophyll; D009584:Nitrogen
keywords: Abandoned arable fields; Chlorophyll; Field chronosequence; Nitrogen; Optimal defence strategy; Pyrrolizidine alkaloids; Senecio jacobaea